THE WAY TOWARD WISDOM
An Interdisciplinary, Intercultural Introduction to Metaphysics

Chapter IV: The Culminating Foundational Theorem of Natural Science

A: The Prime Movers of Systems

1). All Systems of Interacting Bodies Have Prime Movers

The previous chapters have provided an analytic description of changeable substances, derived chiefly from Aristotle, from which it should be evident that changes take place not in isolated substances but in interacting systems of substances. Each such system is a causal series of bodies activating other bodies in which any observed effect has to be explained as the result not only of immediate causes but also of that whole system of causes. For example, the life and behavior of an animal ultimately depends on a series of agents through which it derives its energy. This series ends only in the sun as the chief source of energy on our planet. If the sun were to cease to shine, our earth would not sustain life. In current science there are at least four such causal series ending in the four or five fundamental forces that are taken simply as "natural."

These fundamental forces (or rather the substances of which they are natural properties) are "prime movers," a notion familiar from mechanics. No machine can operate without an engine or other energy source. Hence the dream of inventing a "perpetual motion machine" that moves itself circularly forever is recognized as absurd. Hence such mechanical prime movers are only relatively prime, since the spring of a clock must be wound up, the fuel in an engine must burn, etc. Therefore the question of the prime mover of the universe as a total system is unavoidable.

For Aristotle, whose hypothetical universe was a steady-state, eternal system that appeared to be a perpetual motion machine, this problem was especially urgent. Today on the basis of the alternative hypothesis that the universe had a beginning with the Big Bang the same question again presents itself. This Bang is supposed to have been the first event in the vast causal chain that has produced our universe and hence also its prime mover, the ultimate source of all its energy. "What then caused the Big Bang?" [1]To say either that it "just happened" or "it caused itself" would not be deemed a reasonable answer to any other scientific question.

Because this question is general and foundational and thus presupposed to all more specific questions in natural science, Aristotle considered it at length in the last book of his foundational treatise of the whole of natural science, the Physics. his treatment cannot be understood, as some have tried to argue, as a metaphysical insertion, because the whole structure of the Physics culminates in Bk VIII and provides the terms and premises that it uses. [2] Aristotle has shown in the previous books of the Physics that according principle of causality and the analysis of changeable being into matter and form no material substance can move itself, since it is only potentially in act and thus cannot give what it does not have, namely, actual motion.

Therefore Aristotle in the Physics Book VIII needs to confront the question, "What causes the whole universe to be in motion, as it manifestly is? In Aristotle's hypothesis that the universe has always existed this material prime mover is the outer sphere of the universe that by its continual and eternal motion keeps the whole universe in perpetual motion. In recent time before the Big-Bang hypothesis became current the steady-state hypothesis of Hoyle and Bondi had won considerable favor. This theory proposed that this prime mover intrinsic to the universe was the constant "creation" of a small amount of new matter and energy. [3] In the current Big-Bang hypothesis this prime mover would be the original immensely dense and very small mass of matter (the "Singularity") that began to expand at the first moment of the cosmos's existence. [4] What Aristotle recognized and faced squarely was that no matter what hypothesis one might accept about this original material prime mover it could not itself act on anything without being itself activated by some other prime and truly ultimate mover. This mover, not relatively, but ultimately prime, must be able to act without being activated by another as an unmoved mover in the absolute sense. It must, therefore, be in act by its very nature and be a cause free of the potentiality of matter. Aristotle's solution in Physics VIII to this inescapable problem can be formulated in a theorem that is not deductive (a priori, from cause to effect) but from an empirically observed effect to the existence of its sufficient cause (a posteriori) by a demonstration quia (of the fact), a form of argument typical also of modern science.

2). Proof that a First Immaterial Cause Exists

The actual demonstration in natural philosophy on which, as we saw in the last chapter, Aquinas relies to ground metaphysics is that given by Aristotle in Physics VIII and which Aquinas explains and defends in his commentary on that work. He also makes it is own in the Summa Contra Gentiles[5] In all these formulations he treats of this question in a manner proper to natural philosophy and directly based on natural science, namely, by arguing from motion as sensibly known to us to the existence of a First Cause that cannot be material. If one denies the certitude of the Principle of Causality as Aquinas formulates it by denying that nothing can move itself, as Duns Scotus is said to have done,[6] then the concept of real potency is replaced by degrees of act. In such a Platonizing system, as for Parmenides, change becomes an illusion, since Being can never be other than what it actually is.

Though according to Aquinas natural science demonstrates the existence of non-material being, it can know nothing of the nature or essence of an unmoved mover except by inference from the very effects that demonstrate its existence. Of course, such a situation, of course, is not exceptional in natural science, since we often know the existence of certain natural entities by their observable effects. Thus the existence of the planet Neptune, even before it was actually observed, was discovered by its effects on the motion of the planet Uranus and similarly the existence of "black holes" can be known only through their effects.

Therefore we can only conclude positively that such an unchanging First Cause exists and is the cause of the observed effect of motion. Negatively, however, we can conclude three things. First, if our universe is a uni-verse, there cannot be many such substances unless they are subordinated in their existence to one, prime cause of their existence and changes. Second, this prime cause of the effects known to us by our senses is not itself caused. Third, it cannot be a material substance. To some [7] this third point seems doubtful because they think that probably Aristotle arrived only at what he believed to be the outermost sphere of the universe as its prime mover that always exists in motion and thus requires no other cause than its own nature. But as regards Aristotle's hypothesis that the universe had no beginning, Aquinas says, [8]

If the world and motion began de novo it is obvious that it is necessary to admit some cause which de novo produced the world and motion, since all that is produced de novo must take its origin from an innovator, since nothing educes itself from potency to act or from non existence to existence.

Of the contrary hypothesis, Aquinas says, [9]

[Some object that these demonstrations] proceed on the hypothesis of the eternity of motion that Catholics consider false. To this it should be answered that the most efficacious way of proving that God exists is on the hypothesis of the eternity of the world. If this hypothesis is granted, it is harder to see that God exists.

Aquinas even commends Aristotle for preferring the hypothesis of the eternity of the world to its having a beginning because it seems proper for natural science to proceed on the assumption that the universe is as self-sufficient as possible.[10] Yet even on the hypothesis that the universe has always existed an immaterial unmoved mover is required to account for the infinitely continued motion in the world.

Some have also argued that Aristotle's proof of the existence of a Prime Mover in Physics VIII only demonstrates the existence of the outermost celestial sphere, or that it only proves a God who is the cause of the motion of the celestial spheres but not of their existence as substances. Certainly this was not Aquinas' interpretation of Aristotle since he says explicitly, "The opinion of those who claimed that Aristotle thought that God is not the cause of the substance of the heavens, but only of their motion, is false." [11] Since, however the context of this statement is in reference to the metaphysical treatment of the being of the celestial spheres, it might not seem to apply to what natural science says of these hypothetical spheres. Yet in his commentary on Aristotle's Physics VIII [12] Aquinas takes pains to refute Averroes who interpreted Aristotle as maintaining that the celestial spheres are pure forms that exist with absolute necessity, that is, without any potentiality for non-being. Hence Aquinas explicitly denies that Aristotle's proof concludes only to the motion of outermost celestial sphere, [13]

In the foregoing arguments [of certain commentators] it is supposed that the first moved thing, namely the celestial body, is moved by itself. From which it follows that it is ensouled; which by many is not conceded. Yet to this it must be said that if the first mover is not said to be self-moved, it is necessary that it should be moved immediately by what is entirely non-moving. Hence Aristotle draws this conclusion with a distinction, namely that it is necessary either to come immediately to a prime unmoved mover, or to a [relative] self-mover, from which again one comes to a prime unmoved, separate, mover.

Thus in Aristotle's hypothesis of the eternal motion of the celestial spheres and hence of their eternal existence of the celestial spheres these spheres would have a factually "necessary" existence, that existence would nevertheless not be absolute but dependent on the First Immaterial Cause. There is no contradiction, Aquinas says, in something being at once necessary in a relative sense, yet dependent on a higher cause that gives it necessity.[14] Thus since the celestial spheres are potential not only as regards motion but also as regards their existence, their eternal existence must be received from the Unmoved Mover and thus be distinct from their essence. For Aquinas this reading of Aristotle is necessary in order to make valid the demonstration of the existence of a first immaterial cause given in Physics VIII. Since this work pertains to physica, that is, natural science, this demonstration cannot be metaphysical, but is presupposed to metaphysics, that is, First Philosophy.

Yet, even granted the validity of this physical demonstration of the existence of the unmoved mover as the cause of the motion in the universe, some still doubt that this unmoved mover is the Creator, that is, the cause of the very existence of the universe. This doubt is plausible, I believe, only if one neglects to understand this demonstration in the context of the whole development of natural science in Aristotle's Physics from which Aquinas draws his argument and only if one forbids Aquinas to carry this argument to its logical conclusion beyond the point that Aristotle developed its consequences in his surviving texts.

For Aristotle natural science demonstrates that motion (or change in general) is the natural and proper act of existing changeable, material substances and hence manifests the nature or essence of these existents, that is, that they are essentially changeable. The reason for this is that they are composed of matter (potency) and form (act). Basing himself on this conclusion of Aristotle, Aquinas then shows that existent substances composed of matter and form must also be composed of essence and existence. Hence no body can give itself esse, the act of "to be," any more than it can give form to its matter, that is, move itself. Aquinas' reasoning for this further conclusion is that matter receives its existence from its correlative, but cannot do so unless the form is not merely possible but actual. Forms of material things, however, do not have existence of themselves, since they exist only as an actualization of a matter.

Aquinas considers the possibility that a form might be able to exist without matter, as he really believes to be the case with the angels. Even such a pure form, however, unless its very essence is to exist, would have to receive its existence from the absolutely Unmoved Mover. A fortiori this is the case for the human soul that naturally requires a body and for all material things composed of matter and form. That ordinary substances composed of matter and form do not exist by their very nature is evident in our experience, since we observe that all such substances come into existence and pass away. Even if we consider the hypothesis that there are some material substances (Aristotle's celestial spheres) composed of an extraordinary kind of matter that exists eternally in motion, yet if they have a matter-form composition their existence cannot be self-explanatory but requires another agent. If such an agent is material, it cannot produce eternal motion, and, if immaterial, cannot be a finite intelligence, but must be the absolutely Unmoved Mover. No step in this argument requires a metaphysical notion of Being as ens commune but only the analysis of ens mobile proper to natural science. If the argument were proper to metaphysics, it would be circular since, as we have seen, metaphysics presupposes its conclusion, namely, that immaterial substances exist.

This argument from effects to cause for the existence of a First Cause of the universe and of its non-materiality can be formulated as follows.

1). With our natural senses we observe changeable substances, A, B, C…in the process of change and first of all in motion. Thus by rational analysis we know A exists and we can define it with a real and essential definition by finding a certain unity among its observed categorial properties.

2). Since by the principle of causality that nothing that is moved moves itself, A's observed motion must be caused either by some other material or non-material agent B as its efficient cause.

3) The efficient action of B is either essentially identical with B in which case it is Z, the prime unmoved mover of the motion, or it is only some mover C whose action also depends on the action of Z.

4) The number of movers that like C act to move others only when it is itself moved cannot be infinite, since in an infinite series of such moved movers there would be no prime mover Z and hence none of the intermediate agents would be in act but only in potency to act and hence not actually causing motion..

5) Therefore, Z, a prime mover that requires no other mover to act exists, but it cannot be a material mover, since no material thing either moves itself or is in motion without being moved by another.

In this demonstration no term or principle is used that has not already been directly observed by the senses or that is intellectually directly evident from an analysis of the data of the senses or demonstrated logically from such premises. Thus this theorem pertains to the foundational generic subject of natural science not properly to any other science. Hence it is presupposed to all the more specific conclusions of natural science, that is, to all of modern science that refers to the fundamental forces of gravity, electromagnetism, the weak and strong nuclear forces, and perhaps a counter gravitational force called "dark energy" that explains cosmic expansion. [15]

Each of these fundamental forces is treated in modern science as a natural property of certain kinds of bodies to which all natural phenomena are thought to be ultimately reducible. Scientists today in all their explanatory theories recognize such fundamental natural, material forces as ultimate causes in the physical order. Even if other fundamental forces pertaining to as yet undiscovered particles or other material entities, such as "dark matter," are eventually found by scientific research the argument will still hold. This will be true even if, as Aristotle hypothesized of the celestial bodies, these ultimate properties pertain to bodies composed of a different type of matter than is now recognized by science. All that is supposed is that these bodies are subject to some type of change that at least involves quantitative properties and motion, that is, that they fall within the scope of natural science.

In the case of the relatively prime material movers two possibilities present themselves. (1) They may be only potentially in motion and, since they are prime in the order of physical, material movers therefore require to be set in motion by a more ultimate mover or efficient cause that is immaterial. (2) Or their efficiency is "natural" to them, so that when any obstacle to their efficiency is removed their effects immediately follow, as, for example, modern science holds for gravity and the other three fundamental forces. The obstacle to their action can be either (a) some counter force holding them back or (b) the lack of a suitable receptor body on which they can act. The first possibility is the simpler and is accepted by some authors, but Aristotle takes the alternative possibility as the more difficult for what he is trying to prove. Yet even on that assumption the argument still holds, because in that case the body having a force that is naturally in act when not impeded still has that act as a property. But when bodies are produced by other bodies, they receive their properties along with their substantial nature or essence. This causal chain of production again requires an immaterial prime mover, because changeable beings do not exist necessarily but are produced and perish.

Such natural forces always in act when not impeded are active qualities that are properties of various kinds of bodies. The properties of a substance necessarily belong to it not because the substance efficiently produces them, but simply because they are necessitated by the form of the substance, that is, they depend on the substance by formal not efficient causality. Hence Aquinas (borrowing a term from Neo-Platonism) says that these properties "emanate" from the substance without efficient action. [16] Thus in Aristotle's own chemistry, heavy bodies, when not supported by another body, naturally move toward the center of the earth without requiring any efficient cause of that motion. Yet they could not do so unless the immaterial First Cause efficiently produced them as a certain species of body having that property of motion toward the center of the universe.

Similarly in modern science it is taken for granted that bodies that naturally possess one of the four fundamental forces will exert that force whenever not hindered. Massive bodies will attract each other gravitationally; electrically charge bodies will attract those oppositely charged and repulse those of the same charge, etc. No further efficient cause is sought for these activities, though it is also recognized that bodies would not have these properties unless they were themselves produced. For example, scientists inquire how massive and charged particles come to exist with these properties. It may turn out, of course, that what were thought to be bodies naturally possessed of fundamental forces actually were produced by other physical material forces and hence were not strictly fundamental and "natural." Nevertheless such a regress cannot be infinite. Some forces that are truly fundamental and simply "natural" must exist.

For later Aristotelians the great puzzle was how to explain projectile motion. A ball obviously has no natural tendency to fly through the air, yet when struck with a bat moves until stopped. [17] Aristotle himself tried to reconcile this obvious fact with the principle that "Nothing moves itself" by supposing that when the ball is struck some force is communicated to the medium through which it moves which then keeps it moving after it has left the bat that put it in motion. This seems to us absurd, but we should recall that today science still relies on the notion of "field," that is a medium, to explain the motion of bodies through that field. The Aristotelian commentators, beginning with John Philoponus (fl. 6th century CE) however, preferred (rightly in my opinion) to say that an impetus or force was imparted to the ball by the stroke of the bat. While they considered gravity to be a fundamental, natural force, a property of certain bodies, the impetus was a secondary type of force, accidental (preternatural) to the body that received it.

In this way the later Laws of Motion of Newton could be accounted for, since the impetus would keep the ball moving until stopped by another force. Moreover, since it was not strictly natural, but secondary, it need not be predetermined to some specific result (final causality, teleology). To this explanation we can add that such an impetus is, as it were, "second nature" to the moving ball. Hence the impetus is not an efficient cause but a quasi-property, that can be eliminated from the body in a way that its true properties are not. A heavy body remains heavy even when another body stops its motion, but a ball will not start moving through the air without again being struck. Thus as long as any force whether strictly natural or imposed can be traced back to fundamental physical, material forces that are natural, the argument for an immaterial Prime Mover still follows. As previously noted, [18] Newton realized this problem when he concluded that the gravitational force on which his whole system was built required that God as Prime Mover will its action.

Current science simply ignores the question, or refers to Kant's claim to have refuted the classical "cosmological argument" for God's existence. Kant's refutation holds, however, only if his idealist epistemology is accepted. He argued [19] that only the types of proof for the existence of God are possible: (a) a physico-theological proof that would argue from empirical effects to the First Cause; or (b) a cosmological proof that argues from an experience that is purely indeterminate (being); or finally (c) an ontological proof that argues a priori from the concept of God. Aquinas rejects the ontological proof because it is a priori and the cosmological proof as Kant understands it but supports the physico-theological proof because with Aristotle he holds that necessary truths can be derived from sense experience and it is this Kant (and the only Platonic tradition) denies. Kant's refutation of the cosmological proof raises difficulties for the Existential Thomists who attempt to argue from the notion of metaphysical being. It does not, however, affect Aquinas' argument from our experience of motion and of ens mobile and hence not from the judgment of esse taken to refer indeterminately to immaterial as well as material being.

Furthermore, modern scientists realize that if more than one such fundamental force exists, these autonomous forces would not produce the universe as a unified system, unless these forces are somehow unified. That is why a principal task of current physics is the development a "Grand Unified Theory" (GUT) [20] that will show that all four fundamental forces were originally one single force at the moment of the Big Bang and were only gradually differentiated. Thus it is supposed that this law of the unification of the forces of matter and energy is a property of material substance. Since no material thing can change itself, the question therefore remains, "What accounts for this original force existing in act?" Thus natural science cannot escape this question and, within the limits of its own proper scope and method must try to answer it by the foundational principles of natural science itself, as Aristotle tried to do.

The proof from motion of the existence of a first immaterial cause of all material changes given in Physics VIII was adopted by St. Thomas Aquinas' as the first and "most evident" of his famous "Five Ways" to demonstrate the existence of a First Cause.. [21] The Second Way from efficient agency and the Third from necessity are variations on this First Way. Once we understand the First Way based on the observed effect that is motion, the Second Way argues from the agents or moved movers that cause the motion. Furthermore, if we consider the efficient causality of these agents we see that the action of the first immaterial cause is necessary if they are to act, since the fact that they as moved movers are in act is merely contingent and this is the Third Way. Thus the first three of the Five Ways are based on three effects all related to efficient causality: (1) the effect of motion; (2) the effect of agency of the moved movers; (3) the necessity of the first cause for these contingent agents to act and produce the observed motion.

The First Way is the most evident because through observing a motion we recognize its agent, and through seeing that this agent cannot act without being activated by another agent, we perceive the contingency of its action and hence of a first uncaused (necessary) cause. The other two of the Five Ways Aquinas uses to prove the existence of what "everyone understands to be 'God,'" [22] namely, those through formal and final causality will be discussed as proper not to natural science but to First Philosophy. Whether this First Cause is really the "God" of the monotheistic religious is a question to be discussed later.

Comment by J. Kenny OP
First, distinguish well between "being in motion" and "being set in motion". What is "in motion" is not now being moved by another, but has a formal cause of its motion, that is inbuilt gravity, or a transitional impetus imparted by another and remaining in the body until resistance removes it.
Secondly, understand what it means "to move" activily. It does not mean "keeping something else in motion", but "imparting an impetus". That may be continuous, as the engine of a car keeps running to keep renewing the impetus of the car that is constantly being depleted by resistance.
Thirdly, distinguish well between an essentially dependent chain of movers, such as my hand moving a saw which cuts wood, and an accidentally dependent chain, such as a father who begets a son who begets a grandson. In the first case there can be no infinite series, in the second there can (as Aquinas admits with regard to the possibility of an eternal world).
Fourthly, note that Aquinas' proof, where it is discussed in detail, as in De coelo, motion on this earth is seen to depend on weather and seasons which are subject to the motion of the sun. He thought the sun was moved partly by an angelic mover and partlly by the star sphere with its own angelic mover. He argued that the motion of the heavenly bodies, because it is forever, requires infinite energy or fuel, which cannot be contained in a finite body, and so must come from a spiritual source. He never applied the notion of impetus, which he admitted in the case of a bouncing ball (Physics, IV, lect. 8, n. 1035), to the cosmos. Once we do apply the notion of impetus to the heavenly bodies (like satellites), we see that no mover is required for the heavenly bodies now or for countless past years.
Contemporary knowledge of the universe, however, points to a Big Bang 15 million years ago, which sent things flying in an ever expanding universe. Fr. Ashley discusses this below. It is only in that context we may argue for a First Mover.

B: The Special Case of the Human Soul

Aristotle in Bk. III of the De Anima, and Aquinas in his commentary on that work, but also in many other places, [23] apply the principle used in Physics VIII in the demonstration of a First Immaterial Cause to the problem of the human soul. Aristotle's De Anima, like his Physics Bk VIII, is often treated as a "metaphysical" work. But in fact for him it treats of an integral part of natural science and is continuous with his study of comparative zoology. He considers animal psychology and especially human psychology to be, after the study of the total cosmos, the highest and most synthetic part of natural science. Humans are interested in the whole universe but we are especially interested in ourselves and how we fit---not always very comfortably---into that universe.

Unlike Descartes who was later to claim that animals are automatons without cognition or feelings, [24] Aristotle held that animal sense cognition is true, conscious cognition. He argued that a form can be received in matter into two ways. First it can be received as the form of a correlative matter so as to constitute a substance or, as in the case of an organ in a living substance, to constitute a part of a substance. Second, a form can be received as a modification of some quality (especially an active quality) that belongs to a substance as one of its properties, without constituting any new substance or part of a substance. Any of the powers of sensation (touch, sight, hearing, etc.) is such an active quality, and as such is the form of a sense organ. When the form of an object is received in this power of sensation, it is received as a form of the organ (for example, skin as the organ of touch is compressed by the tangible object). But it is also received as the form of the form of the organ so that the sense power is modified and specified to produce a specific cognitive act. I feel something touching me in a definite way. Thus cognition (consciousness or awareness of an object) is the acquisition of the form of an object, not primarily as the knower's own form (the physical change in the organ) but precisely as the form of the other, that is, the object.

For example, when I touch a piece of ice, if the ice did not cool my hand and my hand simultaneously warm the ice, I would feel nothing. The ice is the cause of the specification of my sensation so that what I sense is something cold not hot. My resultant act of sensation is not as such an act of the object (it is heated by my hand but feels nothing) but my own act as a living organism having the power of sensation. Yet what I sense directly is not just the cooling of my hand, but principally the coldness of the ice. Hence my act of sensation is of a different order than the mutual physical acts of the ice and of my hand as material bodies reducing each other to an equal temperature. This difference constitutes the act of cognition as non-material, although, since it is sense cognition, it cannot occur without a material organ that undergoes some physical change.

This difference between a form received in the mode of material change and in an immaterial mode of change, while true even of the sense of touch, is more evident in the case of sight in which visual objects specify my sensations in a very complex manner (e.g., all the details of a printed page) yet the physical change in my eye required for this specification is very minimal (an image on the retinas of my eyes).Thus when I "know" an object I become that object as regards its own form yet I remain myself as regards my substantial constitution from a correlative form and matter, my soul and my body. In this way when I see an elephant I remain a human being yet also possess the information that tells me that the elephant exists and what it is.

Thus the sense power when affected by a material object is able to respond in its own action in a specific way receptively conditioned by the object that has specified and stimulated its response. An act of sight is never just "seeing." The seer sees something, a specifying object, even when it is only a foggy blur of light. Hence this way of receiving a form as a modification of a form in contrast to the material reception of a form by matter can be said to be an immaterial (or even "spiritual") mode of reception, although in sense cognition a material sense organ is necessarily involved.

What is received from the sensible object is, in modern terms, "information" about that object as it is divested of its particular matter. In modern discourse, however, there is often much confusion in the use of such terms as "experience," "sensation, " sense data" between (1) the object sensed or experienced, (2) the knower's psychological process, and (3) the knower's self-consciousness of her or his positive or negative reactions to the object or attempts to verbalize this total "experience." It is on this maintain the primacy of the object in cognition on which all the rest of the "experience" depends and without which there would no such thing as cognition.

In sense cognition the object known is in contact with the organ by which it is known, either directly as in touch, or mediately as in sight and hearing. The sense power is thus acted upon by the object so as to determine that power to a specific act of knowing. Thus, as in all cognition (as has already been explained) a form is received in a form. Each of the five powers of sense are active qualities pertaining to the Category of Quality, but they cannot perform a specific act of sensitive cognition until they have been specified to perform it by the form of the sensed object. This form received in the form of the sense organ enabling it to perform a specific cognitive act is called the "impressed likeness" of the object (species impressa) that renders the object immediately present to the knower. This likeness or image is then recorded in the internal sense of memory and becomes available to the other senses..

Intellectual knowledge, however, knows the sensed object abstractly in order to distinguish its essences or nature unconfused by mere accidents, or even by its properties, since they are not the essence but its effects. Hence in intellection the act of knowing does not directly contact the object in its physical complexity but as universalized. I recognize you intellectually not in your individuality but as a human being. This means that the intellect that actually knows (the intellectus possibilis) has an object known as an abstract form (species expressa), not, as in sense cognition, the immediately present physical object. [25]

Yet as a power the intellect, just as a sense power, cannot perform a specific act of knowing without first being determined by some object to do so. In other words, it too must receive a species impressa from the object, which it does through an image provided by the external senses and recorded and refined in the internal senses. This demands, however, that the sensed object be made "intelligible" that is rendered abstract and hence, since it is the cause of a different effect, requires a different power than the possible intellect that actually is to perform the act of knowing.

Therefore, the agent intellect (intellectus agens) that renders an object abstractly intelligible as an essence is a distinct power from the receptive intellect (intellectus possibilis) that is "impressed" by this abstract form and thus specified to produce an abstract "concept." Thus Aquinas compares the active intellect to a light that renders a sensible object visible. [26] What we see is not the light itself but the object made visible. So in intellection what we know is not the work of the agent intellect but the concept that the agent intellect makes abstractly intelligible for the receptive intellect to know by its own act. Commonly Aquinas and Thomists generally speak of the two powers together simply as "intellect" an active quality, since the act of knowing as such is in the receptive intellect. The argument that intellection must be caused by an immaterial prime mover applies primarily, however, to the agent intellect. Yet, since the possible intellect produces an abstract concept freed of the material conditions of its object in its existential state, it too must be immaterial and imperishable. Of course this leaves another difficult question: if the human soul is immaterial it cannot be corrupted by the death of the body. It must, therefore, survive as a pure form. How is this consistent with the fact that matter and form have a correlative existence?

To understand this developed Aristotelian non-dualistic conception of the human material substance whose form is a non-material intellectual soul it is essential to note that the soul is a formal rather than an efficient cause. Hence it is not the soul as such but the human substance that it informs that acts as a prime mover of the activities of the various powers that are qualitative properties of each human substance. Among these powers the agent intellect is the prime mover of all the rest, although the lower powers also have a certain degree of autonomy. [27]

Hence, the human soul, although immaterial, informs the differentiated bodily organs as parts of that one substance that is the human person. Thus these organs are enabled to function with the generic vegetative capacities of nutrition, growth and reproduction and the generic animal capacities for various kinds of sense cognition. Moreover human persons informed by souls with immaterial powers of intelligence and free will act as prime movers through these specifically human spiritual powers.

These spiritual faculties need no material organs yet depend on the material organs as their instruments for obtaining sense data and for executing the free choices of the will. Modern biology shows that the brain is the organ of internal sensation (memory, imagination, etc.). Yet, since intellection depends on the sense data that these internal senses store and synthesize, the brain is the immediate instrument of the intelligence and will but does not itself perform these abstract, spiritual acts.

Aristotle, therefore, would have no objection to those who claim that consciousness can be explained as the act of a material organ such as the brain, or that a non-living material computer can be a crude analogue of a living brain. He would, however, deny that any cognitive act can be reduced simply to the physical change that in sense cognition is the specifying stimulus of any sensation. Moreover, the consciousness he attributes to animals is consciousness of objects, of the environment through which the animal must move, of edible objects, of possible mates or enemies, and of an animal's own pained or pleasured body.

Yet Aristotle did not attribute to any animal, except the human animal, a subjective self-consciousness of its own acts of distinguishing between the essential and the non-essential in things---no animal thinks like a scientist, but all humans can do a little science. Even unlearned humans recognize what are the causes of some ordinary effects in their lives. We are all puzzled and seek answers. Hence Aristotle did not attribute to subhuman animals the capability of freely choosing between alternative means to an end---no animal has moral responsibility for its acts. We humans do, and we may choose to try to explore and understand our world. Scientists freely make that choice and freely invent explanatory theories and test them. Humans, but not animals, possess this cognitive power that enables us to make free choices, though both possess the powers of sensation.

Recently it has been shown that certain of the most intelligent animals, such as chimpanzees, not only recognize their bodies in a mirror but when they feel themselves marked on the skin with a pattern they return to look in the mirror to see what change this marking made in their image. Some experimenters interpret this as "self-consciousness" although human infants of less than two years of age can do the same. In my opinion this remarkable behavior does not require self-consciousness. [28] When I feel a fly against my cheek I may look in the mirror to see how to brush it off without, as we say, "thinking twice."

Chimpanzees also need to remove foreign substances on their skin and they instinctively do this by reacting to unusual sensations of touch. Thus when the chimp is marked it instinctively attempts to rid itself of the marking by returning to the visual image in the mirror that it associates with various bodily sensations. This does not mean, however, that it is thinking about taking means to an end, any more than I deliberate about getting rid of the fly on my skin. Its instincts and learning from repeated experiences move the dolphin to make an appropriate response to such a stimulus. The fact that such behaviors only occurs in higher animals and also in human infants indicates that the brain as instrument of specifically human thought must be highly developed to serve mature human intelligence and hence make possible activities that approximate human thought but are essentially inferior to it.

The Greeks called the specifically human power of cognition nous, possibly from the Indo-European root for "to see" from which is also derived the English "to know." In Latin this is intellectus from the Latin inter-legere, to put together or read, i.e. to see relations. For Aristotle, the empirical evidence for this distinction between sense cognition and intellectual cognition is to be found in the nature of human language and the social and cultural diversities associated with its use. Human language differs essentially from the kind of signals used by some animals, because human language includes not only performative signals such as mating, fighting, or warning calls or the recognition of objects by their names, but abstract concepts including in particular a knowledge of relations. [29]

Relations although real and of the physical order, are not objects of sensation. Animals can sense two equal or two similar things or a thing that is the cause of another and its association with its effects, but cannot sense the relations of equality, similarity, or causality that can only be known abstractly by intellectual cognition. This is very evident in the fact that all human languages contain words that indicate purely mental relations that are studied in logic. Although we form such mental relations in imitation of real relations, they cannot actually exist outside the mind. For example, the mental relations signified by such words as "and," "if," "therefore" and even "is" when that is used merely as a sign of predication, are purely mental. They are, however, formed in imitation of some real relation. For example, "and" signifies a mental relation that imitates the real relation that we know from adding one material object to another.

Moreover, as Aristotle had learned from Plato and perhaps Plato had learned from the mathematics of Pythagoras, the very possibility of a scientific understanding of the world cannot consist merely in a description of phenomena. It requires an analysis of phenomena in universal, abstract terms. Such an analysis is impossible without abstract thought that eliminates data irrelevant to the particular aims of research. This is most simply and clearly seen in the mathematical sciences where the abstract concept of 5 as a universal is certainly not the same as the image of some fingers or other collection formed by physically adding five sensed objects from which this concept is derived. At least that is the case in Aristotelian epistemology, although Plato was led by this same fact to posit innate ideas. [30]

Thus while all human knowledge, just like that of animals, begins with sense cognition or consciousness of concrete objects, it also simultaneously involves an abstract kind of cognition that we call intellectual knowledge without which neither human language nor human science would be possible. When I see an antelope, I see it probably much as a lion does, but (at least if I have previously observed antelopes) on seeing it I also recognize it as something included in the abstract notion of "antelope" as a living, animal substance of a certain species. If I could not recognize it as such, I could not express this event in human language, nor could I proceed to consider whether I wanted to shoot it, capture it and by what kind of trap, or simply paint its picture, or just study it scientifically. Thus again in all human thinking, however untutored, there is a "scientific" or causally explanatory element.

Yet scientists are not scientists when they merely observe antelopes. They are scientists only when they freely choose among the wide range of alternatives supplied by some abstract classification of objects, already at least sketchily formed by an analysis of their sense experiences, to pursue this initial understanding. And they pursue their inquiries further than a hunter might because for them certain observations raise abstract scientific questions about this species of animal and its traits and behaviors. Therefore, human intellectual cognition, though it presupposes sense cognition as its necessary condition, like sense cognition is immaterial, the reception of a form by a form. But unlike sense cognition, intellectual cognition is altogether free of direct dependence on a material organ. It is non-material or spiritual in a strict, essential sense because its act is freed of the material conditions of its objects by its power to abstract from them and to distinguish what is relevant to knowing the nature of the object and what is not. [31]

This conclusion of Aristotle in De Anima III is, of course, highly contested today by those who believe that even abstract thought is entirely explicable as an action of our material brains and that some day computers will be invented that will think like humans. But scientifically this "mind-body problem" remains highly controversial. Thus the noted physicist Roger Penrose in his, The Emperor's New Mind: Concerning Computers, Minds, and the Laws of Physics [32] can declare that this problem is still unsolved and may be insoluble by the present methods of natural science. Unfortunately in these current discussions little attention is given to Aristotle's proposed solution and to the still more developed arguments of Aquinas.

Aquinas chiefly emphasizes two related arguments to show that the human intelligence, though it depends on a material organ for its sense data, cannot itself be properly and essentially a function of any material organ. [33] The first of these arguments is based on Aristotle's analysis of the difference between a concrete sense image and an abstract concept based on it. [34]. Even when a sense image derived from an external sense is rendered more general by the internal senses and hence more vague and confused, it always retains something of the concrete singular from which it was derived. For example, my image of a dog may blur the difference between a bull-dog and terrier, yet this image always has some size, shape, and color, however generalized and confused. Like a composite photograph in which images of several faces have been superimposed it is vague and blurred as if out of focus. It was John Locke's failure to distinguish such a generalized images that he called "ideas" from true universal concepts that gave rise to modern empiricism. [35]

This ability of our internal senses to form generalized (and even synthesized) images explains why most animals can instinctually recognize members of their own species and their enemies of other species and can learn to recognize human beings as friendly. A dog can learn to recognize itself in a mirror by associating that image with its sensation of its own body. Such behavior can result from generalized images that are similar to each other, much as Locke and other nominalists supposed universal concepts to be formed. But such generalized images, although they play a necessary role in the formation of abstract concepts, differ radically from them.

I can note the similarity between two oranges, two apples, two dogs, and two men and form generalized images of a pair of blurred objects, but this image is not identical with my abstract concept of the number 2. I cannot think mathematically if I try to use only that blurred image. My intellectual concept of 2 or of a dog abstracts from all these individual differences to retain only what is essential and specific. Since this conceptual act is abstract and thus free of the details of the object as it is concretely material it could not exist in the intellect if that were a function of a material substance such as the brain. A failure to distinguish between sensible similarity and abstract essential identity is precisely the defect of Nominalism.[36]

Aquinas' second argument to show that the human intellectual power is immaterial is based on the human capacity for "self-consciousness" in the strict, subjective meaning of that term. Indirectly and implicitly I am usually, thought not always, aware not only of the objects I am thinking about but that I am thinking about them. Yet for me to know my act of knowing and that it is my act explicitly and directly I must reflect on that act and, since it is the act of a subject that is a substance, on my self as a thinking substance. I must objectify my own subjective act so that the fact it is my act becomes irrelevant and it is considered simply in its reality the act of a certain human person that I am observing who happens to be me. Thus the primary act of knowing is specified not by its subject, the knower, but by object that is directly known and for human knowing this is not an intellectual act but a sensible object. Hence self-consciousness presupposes the existence of sensible object, at least the body of the self-conscious person. Otherwise when I try to reflect on my act of knowing it is either a blank or it is an object that I know has only mental existence and is somehow derived from some sensible object known directly and primarily.

Sensible objects, however, have quantity or extension. Hence a material thing, such as a sheet of paper, although it can be folded ("reflected") over itself many times, can never be reduced to a point. No matter how many times it is folded it always has at least two points that are not in contact.[37] But when I know a sensible object I am at the same time indirectly and more or less explicitly aware that I am knowing that object. Thus to be self-conscious, so to speak, to have myself all together as at a point, since I reflect on my thinking self as thinking. I not only know but I know that I know, etc. Thus in knowing that I am thinking about some sensible extended object I become aware that I am somehow very different than such material objects of which I am primarily aware. They are extended objects but my awareness of myself as knowing them is not of a spatially extended object but has no extension; it is "all together" in a synthetic unity. Thus I am primarily aware of objects whose materiality I also somehow share in my bodily existence but I am also aware that in my totality as a thinking self I am not material. This, however, as such, is a negative understanding. I can gain a positive understanding of myself as spiritual only through the kind of reasoning developed systematically and scientifically in De Anima III.

Thus to become directly aware of oneself as thinking, the Cartesian cogito, is phenomenologically not our ordinary way of thinking in every day life but requires a special kind of reflective cognitive act. Descartes, Kant, the Transcendental, and the Phenomenologists consider this reflection to be the basis of phlosophy. The founde rof Phenomenology, Edmund Husserl spoke of it as the philosophical attitude in contrast to the "natural attitude" of daily life. Indeed we have all experienced moments when we, while very much occupied with the external world, suddenly become conscious of ourselves in distinction from that world. I know that I am knowing intellectually as well as sensitively. In doing both I am aware I am doing two quite different things, one activity that is animal and bodily, but another that mysteriously transcends my animal operations of sensation. In this reflective knowing of myself in the world I experience a certain freedom that places me to a degree in control of my world and myself and enables me to face questions about them both in relation to each other. I become able to consider different possible answers to these questions and different possible practical responses to them. Nevertheless, for Aristotle and Aquinas the "natural attitude" is more fundamental than the reflective attitude and is prior in certitude and must not seek to be detached from it less it become empty of content.

Only a mathematician like Descartes lost in abstract reasoning and forgetting its derivation from sensible material reality was likely to make such an error as his Cogito ergo sum. But at least he was right to claim that he knew with certitude that he was a thinking self and that therefore that he really existed and was not just dreaming. Dreaming pertains to sense cognition so that animals also dream, while intellectual cognition belongs to waking contact with reality. [38] But, for all Descartes' talk of clear and distinct ideas, precisely what it means to say that "I am thinking," or what I am who is thinking, is far from a clear or distinct concept.

Locke never doubted the existence of the self, but Kant also denied that from phenomena we can know ourselves as substantial souls or persons.[39] All we know, it can be argued, is the stream of consciousness itself. In an Aristotelian epistemologically, however, the existence of extra mental sensible substances is what we first know and from this come to recognize that we are ourselves are such a substance with the remarkable and distinct properties of sensation and intellection that depend for their existence on our substantial selves. Thus what we know of ourselves is first our body among other objects. From what our body receives from other objects and can do to them we come to know the self as a living, then a sensing, and finally a thinking body that can perform acts of free choice.

From our modern understanding this argument can be supported by the fact, unknown to Aristotle and Aquinas, that the human brain is made up of a marvelously intricate set of neurons through which messages pass from one part of the brain to another bearing information that can be related to other information. Yet precisely because the brain is material and hence quantitatively extended this network carrying information cannot bring it all to the single point, as it were, of self-consciousness.

Remarkably this argument of Aquinas from reflectivity has also been given mathematical support by the famous theorem of Kurt Gödel.[40] The Logical Positivists and those Analytic Philosophers, who believed that mathematics could be reduced to logic, supposed that any abstract system of thought could be reduced to a finite number of axioms from which all possible conclusions of a science could be logically deduced. Such a "formal system" might then be given a concrete interpretation applying it to the physical world. Gödel demonstrated mathematically that no formal system capable of interpretation in simple arithmetic, having only a finite number of axioms, is able to furnish a solution to all problems that can be raised in its own terms.[41] Yet neither can it be shown to be self-consistent as a system without applying it to simple arithmetic, or to some other data known to be self-consistent from our sense experience of the real world. Because what is impossible in mathematics is also impossible in the physical world (but not necessarily the converse) this means that since computers are programmed according to a formal system, no computer can be constructed that can solve all problems that may in the future be raised in natural science. A new question may always be asked that to answer will require some new principle omitted from the computer's programming.

Aristotle already noted this limitation of any axiomatic system when he said in the Posterior Analytics [42] that in any science there are almost as many premises as conclusions. One can always make a computer to help with each new problem, but each will require a new program that includes the new premise. Why is this? Any formal system adequate to arithmetic, no matter how abstractly it is formulated, applies to what in mathematics is called a "set," that it's a collection of discrete elements. Such a set, though considered at a high level of abstraction, still pertains to the category of quantity, and thus always implies a material basis. Therefore, the fact that human thought, though partially expressed in quantitative terms, and dependent on them for its analogical concepts of immaterial things, nevertheless transcends the material and quantitative and can never be reduced to what any actual computer can do. Thus the human intellectual power of self-reflection and self-consciousness can only be inadequately represented by any specific formal system.

Hence in De Anima III [43] Aristotle comes to the conclusion that intellection cannot be the act of the material body as such but must be the act of an immaterial power. Since, however, he also holds that intellection cannot take place without sensation and sensation must be an act of a material organ, he must inquire what this organ is. Unfortunately Aristotle had to base this inquiry on faulty chemical and physiological data and was led into serious error, just as faulty astronomical data had led him to accept the hypothesis of an eternal world. [44] It was these two great errors that did the most to discredit him in the scientific revolution of the seventeenth century, although they in no way implicated his foundational physics.

The only physical forms of energy that Aristotle knew were light and heat and the medical doctors of his time assured him that when they exposed the brain during trepan surgery they found it cool to the touch. To the touch, however, the heart is the hottest part of the body. [45] On this empirical evidence, Aristotle reasonably hypothesized that the heart must be the most energetic organ. HE argued that since sensation as the highest power in animal organisms, the organ of internal sensation by which the data of the external sense organs is synthesized and stored must be the heart. Moreover, since the doctors also assured him that the surgically exposed brain gave no reaction to being touched, this seemed to support his conclusion that the heart, not the brain, was the prime mover of the body.

This erroneous conclusion seemed to be further confirmed by his famous experiment in which he observed the embryological development of the chicken by consecutively breaking a set of eggs laid on the same day. [46] Since Aristotle had no microscope, the first organ that he could observe in the chicken embryo was the beating primordial heart. Since the cessation of cardiac function was then the best medical sign of death, he concluded, again for empirical reasons, that since animal life begins and ends with cardiac function, the heart must be the prime mover of the body. Yet, just as he had concluded that the material prime mover or movers of the universe must also be moved by a spiritual mover or movers, so he concluded about the material organ, the heart. Since in humans the highest power is not sensation, the function of the heart, but intelligence, a power whose act is spiritual, that intelligence must be the spiritual prime mover of the body and the heart simply its instrument.

Before Aristotle, Plato and, after them both, the great biologist Galen (c.130-c. 200 CE) believed that the heart not the brain was the primary organ, but the question remained moot until first William Harvey, a contemporary of Galileo and like him a well trained Aristotelian, in 1616 showed that the true function of the heart was to circulate the blood. Ultimately by the aid of the microscope modern neurological techniques have made possible a better understanding of the brain's true function as the organ of internal sensation that synthesizes and stores the images received from the external senses. Thus it is the brain that is the primary material instrument of the spiritual human intelligence.

If the intelligence is an immaterial power that needs no proper organ yet does need the body as its instrument for the vital activities and sense cognition, the question of its precise relation to the body arises. The great Muslim commentator on Aristotle, Ibn Rushd (Averroes), noting the silence of the De Anima and the Metaphysics on this question, concluded that for Aristotle there is only a single "active intelligence" for all human persons.[47] While, as a Christian, Aquinas rejected this interpretation because it was incompatible with revelation, he was also convinced that it was entirely inconsistent with Aristotle's anti-Platonic and anti-dualistic conception of the human substance as a form-matter composite. In the unity of the human substance the correlative causality of soul and body demands that the soul's relation to a uniquely quantified body individuate that soul. [48]

For Aquinas, therefore, each human person has a unique soul that constitutes the form of the human body as it is an essential component of the human substance. As such, the soul is the formal cause not the efficient cause of human life functions. Yet by informing the body as a whole and each of its organs it gives to them their specific powers as properties of the human substance. It is these active powers that are the efficient causes of the life functions of nutrition, growth, and reproduction. Furthermore the human spiritual soul as a formal cause of the total person constitutes its spiritual powers of intelligence and free will as the highest and specifying properties of the human substance.

Modern biology shows that the brain is the organ of internal sensation (memory, imagination, etc.). Yet, since intellection depends on the sense data that these internal senses store and synthesize, the brain is the immediate instrument of the intelligence and will but does not itself perform these abstract, spiritual acts.

Why then was Aristotle so cryptic as to the question of whether each human person has a unique intelligence, or whether there is one nous for all human persons? He only says, [49]

Actual knowledge is the same as the thing [known]; potential knowledge, however, is prior in time [to actual knowledge] in an [individual], but, as a whole, it is not [prior] in time. But the [active intellect] is not at one time thinking and at another not thinking. When separated [from the body], it is as such just that [i.e. intellect), and only this [part of the soul] is immortal and eternal. But we do not remember in view of the fact that, although this [part of the soul] cannot be affected, the intellect which can be affected is destructible, and without it, [it] cannot think.

Probably his silence was due once more to his basic hypothesis that the universe is eternal, since this would also entail the existence at present of an infinite number of immortal human intelligences whose bodies had died in the infinite past. He could have escaped this conclusion if he had agreed with Plato in accepting the Pythagorean theory of reincarnation, but there is no indication that he did so. Aquinas, of course, rejected reincarnation as contrary to Christian revelation, but also as contrary to the unique relation of any human soul to its own body.

Of course this leaves us with another difficult question. If the human soul is immaterial it cannot be corrupted by the death of the body. It must, therefore, survive as a pure form. How is this consistent with the fact that matter and form have a correlative existence? Aquinas easily resolved this apparent contradiction once he had drawn from Aristotle's principles the conclusion that to be real the essence of bodies as material-form composites requires the actualization of an existence distinct from that essence to be real. Hence the immaterial form of the human soul when separated from the body by its death, although it no longer has its proper matter, still has the same existence that it formerly shared with its material body. After death that body exists only as collection of various inanimate chemicals in the corpse and its sequela.

Consequently, Aquinas, while maintaining the survival of the human soul says that it is not a complete human person yet is still a substance although an incomplete one.[50] Yet it necessarily retains its transcendental relation to an appropriate matter and this fact supports, but does not prove, the Christian belief in the resurrection of the body to restore human personhood. But what kind of life after death the separated soul could possibly enjoy? Aquinas' attempt to answer this difficult question will be discussed later.

This demonstration of the existence of a spiritual human soul based on the empirical observation of human behavior is a special but extremely important application of the general argument for the existence of an immaterial cause or causes for the changes we observe in our world. It supports the argument for an immaterial First Cause by recognizing in our human experience an analogue, although an imperfect one, to a non-material Prime Mover of the material universe.

C: A Universe of Both Material and Spiritual Substances

1). The Existence of Contingent Pure Spirits

All mythologies and the traditional great world religions, even if they do not have a clear teaching about a unique Creator of the universe ex nihilo, assume the existence of a world of superhuman spirits. The worldview of Secular Humanism tends to contemn such notions as mere superstitions eliminated by modern science, though under its hegemony various forms of occultism such as Theosophy and New Age that assert the existence of such spirits survive and multiply. Even some Christian theologians today reject the existence of angels as unnecessary, since if one accepts a First Cause as Creator, either on faith or reason, no intermediate intelligent causes for natural phenomena are required. [51] Yet it does not accord with the methodology of science to explain observed phenomena by resort to a First Cause extrinsic to the universe before first seeking for secondary causes intrinsic to the universe. To be content to explain all observed effects simply as the acts of God is the fallacy called "occasionalism [52]." Moreover since the foregoing argument for the spirituality of the human soul is based on the same principles as the proof for the existence of a First Cause, why should we not also ask whether a similar proof can be found for the existence of other spiritual beings subordinate to the First Cause? The existence of such contingent, created, but superhuman spirits in addition to the existence of human spiritual souls in no way contradicts the existence and necessity of the First Cause.

Therefore, just as scientific methodology ought to lead us, as I have argued, to ask whether there is a non-material First Cause of the universe, and whether the human intelligence as prime mover of the human body is spiritual, so it demands that we ask whether we observe effects in the material world that manifest the existence of superhuman intelligences. No wonder then that prior to the development of modern science, common sense led the human race throughout the ages and in many cultures to ponder whether such superhuman spirits exist. The fact that most cultures have come to an affirmative answer to this question at least suggests that ordinary experiences somehow empirically manifest the existence of such spirits, though our scientific culture seems blind to this evidence.

Thus in Aristotle's Metaphysics Bk XII (Lambda), Chapter 8 we find an elaborate discussion of the immaterial intelligences, 47 or 55 in number, that he concluded were required to explain how the heavenly spheres continue in perpetual motion. It would seem that this question belongs more properly to Aristotle's astronomy in the De Caelo. Leo Elders, S. V. D. in a study of the De Caelo [53] holds that the several references to these movers in that work are inconsistent and show that Aristotle, although he always held with Plato that the material world depends on a spiritual realm, only gradually worked out the final theory that is preserved to us in the Metaphysics. Even if this was the case the arguments given in the latter work are in purely physical terms not metaphysical ones and belong properly to natural science. [54] Logically the problem of the existence of such spirits, like that of the existence of the immaterial First Cause and of the immaterial human intelligence should first be dealt with in natural science as still another special application of the general theorem about prime movers. First Philosophy therefore should presuppose such existence proofs although, of course, it may have more to say about the essence of spiritual things than does natural science.

Aristotle's proof, as we have it in Metaphysics Bk. XII, [55] is based on what he believed were empirical data well established by the Babylonian astronomers over many centuries. The mathematical theories of astronomy developed in Plato's Academy did not simply reduce the cause of the rotation of the heavens about the earth to a single physical mover, the outer sphere of fixed stars, as is sometimes asserted. Instead, to account for the apparently autonomous motions of the planets (the Greek term means "wanderers") they assigned to each of them a certain autonomy of motion. These autonomous motions were then coordinated by the more uniform diurnal motion of the sun and fixed stars or outer sphere but not simply reduced to its agency.

Aristotle accepted a modified version of these theories and therefore thought that this plurality of independent, though coordinated, motions of the celestial spheres logically led to a demonstration of many immaterial movers, distinct from the First Cause, but subordinated to it. Hence, just as the existence of the immaterial First Cause can be proved from any motion in the universe, so the existence of several immaterial prime movers subordinated to this First Cause can be proved from the relative autonomy that the planetary motions are observed to have.

Since such immaterial movers must be superior to the human spiritual intelligence Aristotle called them by analogy "intelligences" which Christian theology was later to identify with the Biblical angels or "messengers of God." Some ancient commentators thought that these intelligences were the souls of the celestial spheres. But Aquinas points out [56] that for Aristotle the reason that the human body has differentiated parts is to provide material instruments or organs for the different powers of the human soul. But Aristotle also held that the celestial bodies are perfectly homogeneous and thus could not perform such services. Hence the intelligences must be pure spirits without bodies. Thus he would have contradicted himself if he claimed that the celestial bodies were ensouled, since such without such organs they could not perform the activities required for sensing and thinking. Nor would these intelligences require some kind of "incorporeal matter" (whatever that might be!), as St. Bonaventure, St. Albert the Great, and other medievals supposed, in order to be members of a single species. Aquinas, on the contrary, held , as we have seen that because angels are pure spiritual forms each must be a complete species in itself. [57] Hence Aristotle must be understood as intending to demonstrate the existence of spiritual substances, analogous to the human soul in their ability to think and will, but so much more powerful in intelligence as not to require bodies. They are pure non-embodied spirits subordinate to the spiritual First Cause.

Aquinas adds two dialectical arguments to show the plausibility of Aristotle's argument. [58] The first is that the order of substances known directly to us is hierarchical, ranging from very simple things, such as atoms, to very complex things such as the higher animals. In each generic section of this hierarchy there is a similar range, for example, inanimate things range from atoms to complex chemical substances, the plant kingdom ranges from very simple plants to much more complex ones, and the animal kingdom from simple worms to apes. Why then in the genus of intelligent beings do we observe only the least type of intelligence, that of humans who are so dependent on a body to think? Is it not plausible that there is also a range of intelligent beings far beyond lowly humanity?

By a second dialectical argument Aquinas notes that in the hierarchy of beings we observe that as we ascend the scale of complexity the variety of species within a genus also increases. There are only a few species of elements, more species of compounds, still more species of living things, and among these still greater variety among the vertebrate animals. This makes sense, since the more complex the type of substance the more diversity its of parts becomes possible.[59] Hence, Aquinas concludes that probably the species of angels is greater than the species of all material things. This is supported also by the fact that although human beings are all of one species, our intelligence and freedom makes us each highly unique. Thus the vast and ever growing human population anticipates, as it were, the still greater vastness of the population of pure spirits. Hence in the Aristotleian Thomistic universe the material substances studied by natural science and directly accessible to our observation constitute only a small fraction of the created universe compared with its far vaster and more diversified spiritual portion.

2). Does Modern Science Exclude Spiritual Substances?

Does modern cosmology invalidate the foregoing argument? I contend that it not only confirms this argument for the existence of pure spirits but even adds to its force. As was stated earlier in this chapter, current cosmology seeks a Grand Unified Theory (GUT) according to which for not more than 10-39 seconds a single natural force existed. Soon, however it differentiated into the four fundamental forces of gravity, electromagnetism and the weak and strong nuclear forces that have operated the cosmos during its subsequent 15 billion years evolution.[60] Scientists generally accept these four forces simply as "natural" and hence requiring no further explanation. They ignore the foregoing arguments that these forces must be properties of bodies in the Category of Quality and that they cannot act without being activated, ultimately by the First Cause. Once differentiated these forces have been independent of each other through almost all the history of the universe. For example, gravity, though a comparatively feeble force, operates throughout space, while the "weak" and strong forces are restricted to atomic dimensions. Thus, the essential premise of Aristotle's argument for the existence of superhuman spiritual movers subordinate to the First Cause is instantiated by the four fundamental natural lines of causality recognized in modern scientific cosmology.

In Aristotle's astronomy, however, the intelligences were necessary to keep the spheres moving according to their natures through infinite time, since they were inalterable. [61] Other kinds of change than motion could take place only in sublunar matter that was subject not only to law-like efficient causes but also to chance, that is the obstruction of the action of one natural agent by another. The disorder produced by chance, however, was limited and prevented from destroying the order of natural sublunar substances by the regularity of the cycles of the sun and other celestial bodies that also supplied the energy for terrestrial agents.

Modern cosmology, however, is no longer confident that the universe has lasted for an infinite time but holds that it began with the Big Bang and is in the process of an evolution whose direction is not absolutely determined but is subject to historical chance.

The course this evolution has actually taken, especially the origin of life and of human intelligence seems highly improbable, since many alternative scenarios were possible. [62] In the Big Bang hypothesis the original "Singularity" contained all the matter and all the energy of the universe that it has now or will ever have. This, however, is no reason to believe that cosmic history was predetermined in that singularity the way that the future development of a living organism is predetermined (barring accidents) by the information contained in the genetic code of its zygote. Yet that vast information required to produce the human brain was necessary to direct the four fundamental forces to produce intelligent life. The only information that science attributes to the original state of affairs at the Big Bang are the laws of quantum theory that only state probabilities not inevitabilities. As the Nobel Laureate in Physics, Murray Gell-Mann writes, [63]

The fundamental laws of physics allow in principle only the calculation of probabilities for various alternative histories of the universe…Above and beyond these presumably simple principles, each alternative history depends on the results of an inconceivably large number of accidents…Each alternative history of the universe receives a tiny contribution from the simple fundamental laws, along with a gigantic contribution from the quantum accidents…The rest comes from the numerous regularities resulting from 'frozen accidents.'

By "frozen accidents" Gell-Man means the stable entities or systems of entities such as the solar system that we now observe that have as a matter of fact been produced by evolution through a sequence of largely chance events. Perhaps, indeed, the development of the universe as we observe it has resulted from inevitable reactions between its fundamental forces in a broadly predetermined evolutionary sequence. Thus cosmic expansion, the formation of the simpler elements, the condensing of nebulae, the formation of stars and nebulae, the formation of some 92 elements in the stars and of simple molecules can be broadly explained by the quantum laws present in the original Singularity. Aquinas thought that even simple forms of life could be spontaneously generated from inanimate matter by the energy of the sun. [64] Yet at each step toward complexity the dominance of chance increases and the adequacy of this kind of explanation lessens. To explain this history, so largely due to unique, chance events, it is imperative to seek the source of the information ultimately embodied in complex substances.

I do not doubt that as chemists can now produce relatively complex organic molecules that have not been ever observed to occur naturally, so someday they chemists may be able to produce living organisms. To do so, however, what they will need, but do not yet possess, the requisite amount of information to guide them in applying the four fundamental forces in just the right way and the right sequence. Contrary to Aquinas, Louis Pasteur showed that at present spontaneous generation of life never occurs at present. According to quantum theory the outcome of natural processes is predictable only in a range of probabilities. For Aristotle also the laws of material substances are always subject to chance interference and hence hold only in pluribus. Hence to produce a complex substance there must be an agent having information proportionate to that complexity. This can be an agent who is conscientiously intelligent like the chemist in his laboratory, or a bird building its nest by instinct, or an inanimate agent with a natural force that is predetermined to regular effects. Where then is the agent intrinsic to the universe as a total system that has the information required to produce life and the complex human brain used by human intelligence?.

The Darwinian answer, of course, is that the environment and its "natural selection" of chance mutations supplied this information that guided living things to evolve toward complexity. [65] This may well be the case, but it only moves the source of the required information from the organisms to the terrestrial environment that supports and selects the evolution of life. Scientists have shown that the so-called Anthropic Cosmological Principle makes clear how extremely improbable has been the sequence of environmental events required to select our human genome programmed to produce the human brain.[66]

Scientists have purposed various answers to this dilemma. A fantastic one is to posit the existence of an infinite number of universes and then claim that we "just happen" to be in the one in which intelligent life has emerged by chance. Stephen Weinberg [67] and others hope for Ultimate Theory of Everything for a universe that develops according to a mathematical formula requiring no initial conditions. That would mean, however, that the universe is not contingent but necessary, and such a necessary being is what all understand as God! Teilhard de Chardin [68] and others also have supposed that there is a "law of evolution" but this would demand that the information required to produce life was already present before the differentiation of the four independent fundamental forces. Yet this notion, often evident in popular accounts of evolution and reminiscent of cosmogonic mythology, that the singularity contained, like the zygote (fertilized egg) all the information needed to guide its self-development, remains devoid of scientific evidence. But this still begs the question; since it supposes that environmental changes will favor this advance in complexity. Since, however, the environmental changes also are a sequence of chance events, it is less probable that natural selection will favor complexity than that it will destroy complex organisms and favor simpler ones or extinguish life altogether.

Somewhat more plausible is the concept of "self-organization" or "the spontaneous emergence of order" favored by Stuart Kauffman [69] and others. Chance can produce order, as every gambler knows, but only briefly. A sequence of cards can be dealt or a sequence of dice thrown that have a desired order, but from this winning sequence no prediction can be made about subsequent deals or throws. Kauffman supposes that natural selection will guarantee that a sequence of chance mutations leading to a more ordered complexity of an organism will be preserved (as one of Gell-Mann's "frozen accidents") and disorganizing sequences will be eliminated. "Self-organization," as he explains it, is based on the fact that proteins are able to "self-catalyze" their interactions. Moreover these interactions rapidly multiply when the number of different kinds of intermingled proteins reaches a critical point. Hence Kauffman believes that such a complex chain of interacting proteins may have reached homeostasis and began to reproduce itself as simple living cells. While this hypothesis helps to explain how the interactions within an organism are facilitated, it does not explain how the unity of an organism can originate in the facilitation of an increasing number of interactions that might simply result in disintegration of the complex.

Nor again has this problem of explaining the unity of a living organism been solved by "chaos theory" as some popular writers suggest. [70] In fact this interesting theory exacerbates the problem since it is based on observations that show how very small differences in the initial conditions of a change can make an enormous difference in its ultimate outcome. It is also true, however, that chaos theory has shown that random the repetition of certain random processes often uncovers an unsuspected order. For example, swings of a pendulum when carefully observed are actually random in their length and timing yet they converge on an average that makes it possible for a pendulum clock to keep time.

Chaos theory, therefore, does not mean that order can arise spontaneously out of absolute disorder, as the term "chaos" might seem to be imply, but only that random repetition of an event can make manifest some hidden determinism. The random character of a pendulum's swings results from chance currents in the air and other factors that cause minute differences in the initial conditions of each swing. Yet the averaging of the swings and their eventual coming to rest results from the deterministic law of gravity and the fact that they will eventually comes to rest from the probabilistic law of entropy.

Thus surprisingly the fact that the information required to produce the complexity of the human brain cannot be scientifically located in the original singularity or in any of the subsequent states of the universe means that modern science is more favorable to Aristotle's argument for the existence of immaterial spirits than was his own astronomy! We begin to see how utterly improbable it would be for intelligence to emerge from our material universe, so subject to chance, unless some intelligence with the requisite information to guide the process exists. Therefore, if we are not to assume that God has made a universe directly dependent on his constant intervention, we must conclude that he has created pure spirits as part of our universe, to serve him in the guidance of the evolutionary development of its material entities for the benefit of its spiritual entities.

A final objection to the argument, however, can be made from a Thomistic perspective. If we posit that someday a chemist will be able to use the four fundamental forces to produce a living organism, why does this argument not lead simply to the existence of a single created spirit, like the Platonic Demiurge [71] who would possess all the needed information to guide cosmic evolution? It is highly unlikely that any human chemists could ever on his own discover all the information he would need to produce life. Making the atom bomb or landing on the moon required the joint work of many scientists and made use of a vast historical accumulation of information. Pure spirits are contingent intelligences that unlike God are not omniscient. Consequently to posit a single Demiurge is far less likely than the existence of a society of spirits, who, though they cannot create anything ex nihilo, carry out God's plan for the development of his creation according to his purposes. In Chapter VII will say more about such a society of intelligences.

Thus the noted Thomist Charles DeKonink held [72] that Aristotle's argument, freed of its outmoded astronomical data, constitutes a valid and certain natural science demonstration of the existence of many disembodied spiritual substances but one that rests on an hypothesis, namely, the existence of our contingent world with its actual order as observed. Yet this hypothesis is verified by an empirical demonstration and thus has a physical but not a metaphysical certitude. Therefore, though this demonstration holds for our universe, it might not be true in some other world, e. g., one in which no independent lines of efficient causality could be empirically verified. This distinguishes it from its treatment by Aristotle in Metaphysics XII that will be discussed once the validity of metaphysics has first been established. I emphasize that the demonstration of the existence of the First Cause in Physics VIII, though certain, has only the conditional character just mentioned, as do all demonstrations in natural science. Whether it can be given a more absolute character in metaphysics remains to be seen. The fact that the demonstration is conditional, however, does not mean that it is only probable, but that it has a factual certitude rather than an absolute certitude, just as does the demonstration of the existence of pure, contingent spirits.[73]

Thus on Thomistic principles, we must conclude that in an evolutionary universe, the emergence of intelligent life, since it obviously is not directed by human intelligence, must have been directed by pure spiritual intelligences. The fact that they must also be free, opens the possibility that some of these spirits, like some human beings, have chosen out of pride in their own powers, to rebel against the order intended by the Creator, and hence, like human polluters of the environment and of social justice, are working to frustrate the Creator's designs.

Such a war between spirits may, therefore, provide an explanation as to why the course that cosmic and biological evolution has in fact taken seems so subject to chance, irregularities and to violence. The history of our universe has not been a smooth unfolding like a chicken developing from an egg. It has been fraught with the destruction of galaxies and stars, the death of planets, the pounding of the earth by asteroids, the repeated exterminations of whole genera of living things, such as the dinosaurs, and the perilous history of the human species. Our human species has often been very close to extinction by natural disasters as well as by its own misdeeds. This dramatic character of cosmic history has been recognized in the mythologies of all people in all the great religious traditions as a struggle between order and chaos, good and evil. Science has not contradicted this drama but still further exposed its violence. Only Secular Humanism in its optimistic phase has favored a simple story of inevitable human progress, yet even its favored Darwinism is a story, as Tennyson wrote poetically, "red in tooth and claw."

D: Natural Science Validates First Philosophy

1). First Philosophy Presupposes All the Special Sciences

If then, as was just argued, natural science cannot be First Philosophy since its subject does not include the immaterial beings that it proves must exist, might one of the other special sciences undertake this heavy task? Could First Philosophy perhaps be a practical rather than a theoretical discipline? That central figure of modern philosophy, Immanuel Kant, so severely limited theoretical knowledge that he was compelled to leave many questions, such as the existence of God and the spirituality of the human person traditionally included in the scope of metaphysics to a purely practical solution, namely, that without such beliefs the popular respect for morality necessary for a stable social order would be imperiled.

The Marxists too and some liberation theologians have argued for a "unification of theory and practice" in which the ultimate test of truth is political effectiveness. For American pragmatism, of course, the criterion of all objective truth is "Does it work?" In Chapter I it was argued that the Secular Humanism that originated in the Enlightenment, because it trusted in no objective truth except that of a "value free" natural science, was forced to leave to the fine arts or some form of estheticism the necessary task of constructing "values" to guide meaningful human living. In effect this subordinated the objective truth of natural science to the practical construction of a worldview, since even the pursuit of natural science, arduous and disciplined as is, requires some kind of ethical justification. Such positions obviously make anything like a First Philosophy not a theoretical but a practical discipline.

Aristotle, however, ruled out ethics, politics, and the arts or technologies as First Philosophy precisely because they are practical disciplines and maintained that every practical discipline presupposes some theoretical discipline. [74] Ethics presupposes an adequate knowledge of human nature. The technologies use and therefore must presuppose some accurate understanding of natural forces and materials. The fine arts involve the representation of natural objects and so deprive their forms and expressive significance from them. [75] Ultimately therefore, knowledge to be practical must somehow be in conformity with the objective truth of the world and of human nature given prior to our limited human control over nature.

Moreover, as Aristotle demonstrates in the Nicomachean Ethics,[76] ethical behavior requires freedom of choice and this freedom is established as a human property in the De Anima, a part of natural science. Furthermore, the goal of human life is the contemplation of ultimate reality, the object of a First Philosophy that presupposes natural science. Thus also the technologies and fine arts are subordinate to ethics since their purpose is to serve the good life and if unethical are destructive of human existence. Hence the project of Romanticism to make the fine arts and estheticism the ultimate wisdom, though attractive, is illusory. Since ethics and politics are dependent on natural science so are the fine arts that are subordinated to ethics and politics [77]. Hence all these practical disciplines presuppose the theoretical discipline of natural science and therefore cannot be First Philosophy.

Thus we can eliminate the practical disciplines as candidates to be First Philosophy and are brought back to the two kinds of theoretical discipline other than natural science that must be given more serious consideration, especially because it might seem that they too consider immaterial being. A chief preoccupation throughout Aristotle's Metaphysics is the refutation of the Platonic exaltation of mathematics and the last two books of the work are devoted exclusively to this task. For Plato the "mathematicals" [78]or abstract mathematical ideas are the bridge from the material to the immaterial realm of being. However, as we have already seen, Aristotle in the foundational part of natural science demonstrates that the first property of any changeable object is quantity and hence all changing things are extended, that is, are bodies. Descartes was to argue that the essence of material substance is extension (continuous quantity). Yet Aristotle had shown that this cannot be the case since the same identical substance can expand or contract, or, in the case of living things, grow. Instead, as demonstrated in the above discussion of the categories, quantity is the first property of bodies not their essence.

Thus the mathematical sciences consider both continuous and discrete quantity in abstraction from any other physical properties of material things and also from the essence of the substances that have quantity and other properties that presuppose that it is a quantified body. Nevertheless mathematics is not about immaterial existents but necessarily presupposes natural science and is about a property of material things, namely quantity, though only as quantity is abstractly conceived. Hence it cannot be First Philosophy.

Many modern thinkers, notably Gottlob Frege (1848-1925) and Bertrand Russell (1872-1970), have denied that mathematics is founded on physical reality and believe it is a purely formal science reducible to logic. I will attempt to answer this notion more fully later, but here it suffices to point out that if mathematics were logic, then for that very reason it could not be First Philosophy. Although the candidacy of logic or at least of semiotics to be First Philosophy is plausible, since according to the Thomist commentator Cardinal Cajetan (1468-1534) logic is about purely mental being and in the same degree of abstraction as metaphysics. .[79] Yet logic is presupposed to every field of systematic thought including metaphysics and is not a science of the real but of mental relations.

Nevertheless, the Logical Positivists, British and American Analysts, the Semioticians, and the Deconstuctionists, [80] also seem to reduce the questions formerly assigned to metaphysics to the study of the language of the sciences or of ordinary language. But the clarification of language or the exposure of its ambiguities, though necessary tasks for any science (not just philosophy), cannot be First Philosophy unless they also deal with a reality that is independent of and presupposed to any process of human verbal expression. Adam named the animals, says Genesis, but there first had to be animals to name. If analytic philosophy and the deconstructionism that has followed on its wake limit us to "intertextuality" all sciences of the real become impossible. Hence we must admit that these disciplines are dependent on natural science and logic and since neither of these is First Philosophy, they too cannot be Human Wisdom.

First Philosophy, dealing as it must with both material and immaterial reality, the former known to exist through sense experience and constituting the proper object of natural science, the latter known to exist as the conclusion of the foundational part of natural science, therefore, must be a science in its own right. To construct this First Philosophy was what Aristotle undertook in his Metaphysics and rightly named "First Philosophy" (i.e., First Philosophy), or, since it deals with the ultimate immaterial causes of material reality, "Theology." We can conclude, therefore, that not only the practical disciplines but also the theoretical disciplines of mathematics and logic presuppose, though in different ways, the foundations of natural science and cannot, therefore, be First Philosophy or Wisdom.

2). Natural Science is Not First Philosophy but Validates It

From all these considerations it can be conclude that natural science by demonstrating the existence of immaterial cause of motion also demonstrates that though it is epistemologically the First Philosophy in the order of learning, it cannot be the architectonic discipline. It subject is being, but only changeable being (ens mobile). Yet in establishing its own foundations it finds it necessary to explain the very existence of changeable being by concluding first to the existence of an immaterial First Cause and then to the existence of human intelligence and of superhuman spirits. These are all known a posteriori, that is, as unobservable causes of observed effects.

In comparing, as it must, the material things that are effects of the First Cause to that Cause, natural science must conclude that material things exist only contingently, since their existence depends wholly on the First Cause that alone exists necessarily. Thus the famous Thomistic "real distinction between essence and existence in creatures," mentioned in the last chapter, is first manifested in natural science, although its implications for a full understanding of the Creator in whom essence and existence are claimed to be identical remains outside the scope of natural science. Even in natural science, however, it must be kept in mind that existence is proportional to essence, so that the question of "Does it exist?" always leads to the question, "What kind of a thing is it?" since they are correlative like form to matter. As the form and matter of a changeable condition each other, so do its existence (esse) and its essence. Its existence is an act by which its essence is real in a certain way, and its essence limits the manner in which it is real. Both a molecule of water and a human person "exist" as substances in our changeable world, but their activities are very different and a "thing is as it acts." Substances that have more complex actions have more complex essences and correlated existences. To say as some Existential Thomists have done, that Aristotle's philosophy is one of "form," or of "substance" but not one of esse, to be or exist, is wrong, since when he speaks of form or of substance he means existing form or substance not merely possible forms or substances. The act of being (actus essendi, esse) of a contingent being is, in the case of material beings, given to its matter by its actual form. This form has been made actual in the matter by the efficient cause of the being. In the case of a contingent but spiritual being the actual form is identical with its substance. Thus implicitly at least Aristotle is always treating of things in their actuality or esse, in their "being as being," just as is Aquinas. The difference between what they have to say is only that Aquinas makes explicit what Aristotle does not.

Since not only the kind of existence that material things possess, but also the kinds of existence that human spiritual soul and pure spirits possess, are all effects of the First Cause whose own existence we know through these effects, they are contingent, that is, do not necessarily exist. The First Cause, however, as is especially clear from the Third Way of proving its existence, since it is uncaused, cannot have merely contingent necessary existence, that is, its existence and its essence must be identical, while the essence and existence of all contingent things are really distinct. This raises questions that are not the proper task of natural science to answer, but must be left to First Philosophy once it becomes clear that not all existent things are material.

This long discussion, therefore leads to the conclusion that although natural science is epistemologically the First Philosophy it is not the First Philosophy that is the Human Wisdom we are looking for. Yet our demonstration of the existence of spiritual beings that are the ultimate causes of the effects studied in natural science answers Question 1 about the subject of such a First Philosophy, namely, that Being as Being as inclusive of both material and immaterial realities (ens commune) really exists.

E: Dialogue with Other Views of Nature

In every culture there must be, of course, certain dominant or influential though perhaps conflicting views about the natural world of our experience and human participation in that world. I have presented the view of Aristotle in dialogue with modern science. But these two views characteristic of the history of Western culture are only two among many. While it is impossible here to do justice to these other views, I will say something of the mythological worldviews that underlie all advanced cultures and then the two major advanced civilizations of India and China.

The mythologies of all cultures, but especially of those in which the mythological mode of tradition plays the principal role, situate humanity in the midst of a universe of friendly and unfriendly powers. Mythology takes the place of scientific explanations of phenomena and historically scientific explanations often originate and terminate in myths. Thus the origins of Greek science are mingled with mythology, so that to Thales is attributed both the prediction of the solar eclipse of 585 BC and the saying that "All things are full of gods." The historical development of astronomy from the time of the Babylonians was intertwined with that of astrology, and even today the models used in scientific speculation, especially at the cutting-edge of scientific advance, such as the Big Bang hypothesis, the notion of "possible worlds," of the brain as a computer, the Freudian "censor" or Jungian "collective unconscious" have a strangely mythological tone, since they are not subject to direct empirical verification. No wonder that today science so easily generates "science fiction" and then gives that fiction "virtual reality" in the simulated "special effects" made possible by advanced scientific technologies.

The most important cosmological myths have an etiological (causally explanatory) character and relate how the world was created or ordered, how it will come to perfection and how it will be destroyed or undergo a cycle of transformation and destruction. For example, in the mythologies of many cultures the universe originates in the hatching of a cosmic egg or emerges from a vast ocean or river as a hill of dry ground. Or cosmic order results from triumph of a sky-god and his hosts in a war over chaotic titanic forces. Using analogies from human life these new, ordering forces are then pictured anthropomorphically as gods, spirits, or heroes. Therefore, in intercultural dialogue it is essential first to ask about the myths of a culture. Especially significant are myths of the origin of the universe, the differentiation of the various kinds of things that compose it, the forces whose conflicts or harmonies sustain it, and the pattern of its historical development and ultimate destiny.

Even in the most scientifically and philosophically advanced cultures such mythological cosmologies form a background to critical thought and to ethical and political norms. [81] For example, since Darwin, the notion that the universe is "evolving" toward a higher state of intelligence and human freedom is the background of most popular and elite thinking and political decisions although it is more myth than a principle that is critically and firmly established. The myth of "Apocalypse Now" is better evidenced!

The current interest in environmentalism has made us more aware of how such mythical cosmologies, precisely because they are anthropomorphic, help us to feel at home in nature, so that we appreciate the ecological order instead of treating nature as mere alien material for artificial human constructions. Thus the mythological heritage of Native Americans remains of permanent value for our appreciation of the wonderfully varied landscape of our country. This linkage with the cosmos is also enhanced by liturgical sacramentalism. In the Jewish Scriptures the tabernacle and the temple as sacred places and the rites conducted in them effectively symbolized the creation and these symbols have been carried over in the Christian sacraments. [82] Thus the artifacts of civilization need not replace the pristine realities of nature but can retain a symbolic reference to them or on the contrary they can alienate us from our natural roots, as is all too evident in some of our anti-human urban congestion.

I have emphasized the unique contribution of Greece as it moved beyond a mythological worldview to develop pure mathematics and the critical methods of natural science. Parallel developments took place in the great centers of civilization in India and China. While in Greek and Roman times there was some interchange between the culture of India and the West, it was not until the late eighteenth century that Western scholars began to explore Indian literature. They only gradually became aware that India's ancient culture rooted in the Vedas was profound, rich, and varied. They learned also that the non-Vedic worldviews of Jainism and the slightly later Buddhism have also addressed the problems of cosmological theory.

Jainism teaches that the universe consists in an infinite number of eternal uncreated and independent atomic substances that are either lifeless (ajiva) because in them consciousness is dormant, or living and conscious (jiva). [83] There are five categories of being: (1) space; (2) time, (3) a subtle fluid or energy that causes motion; (4) another subtle fluid or energy that causes rest; (5) atomic matter. This matter is of five types, earth, air, fire, water, and vegetation. As it is moved or rests in varying arrangements, it produces changing bodies in space and time. It ranges from gross sensible matter to a subtle matter that fills all space and that stains sensible matter in an eight-degree spectrum ranging from evil to good (karma).

Living things consist in a subtle form of matter but are stained by evil karmic matter that causes it to be united to the gross, evil matter of the body. It is this staining of the souls, of which there an infinite number, by karmic matter that causes them to transmigrate from body to body until by severe asceticism they gradually free themselves from the darker stains and finally become perfectly transparent. Each of these transparent bubbles then rises to the top of the universe, pictured as the skull of the Cosmic Man. They remain there forever in complete isolation from each other with a consciousness free of any particular content that could cause suffering. Jainism, however, has a cosmology that explains the universe atomically somewhat as did the Greek Democritus. But by its distinction between gross matter and souls as atoms of very subtle matter it accounts for the basic Indian belief in the cycle of transmigration. Thus Jainism does not make a clear distinction between the material and the spiritual and is perhaps best viewed as a kind of panpsychism in which materiality is only a fallen condition of spiritual realities.

Buddhism's attitude to cosmological speculation is primarily negative, since it teaches that release from the suffering of transmigration is to be achieved principally by realizing the emptiness of all phenomenal existence whether material or spiritual. [84] Thus, as for Jainism, for Buddhism the goal of cosmological speculation is release from the suffering of reincarnation by the emptying of consciousness. Contrary to Jainism, however, Buddhism denies the existence of individual souls. Essential to the Buddhist worldview, therefore, is its theory of "the wheel of dependent origination" according to which all sensible phenomena and the stream of conscious ideas from which we derive the notion of an individual self (atman) are produced by five "aggregates" (skandhas): (1) bodily matter, (2) sensation, (3) perception, (4) desires, and (5) consciousness. These skandhas last only momentarily in a "life-stream" and then yield to a new aggregation of insubstantial impressions. Thus for the Buddhists natural science is concerned with an endless cycle of impermanent and empty events about which detailed inquiry can only increase our illusions concerning the permanent stability of the phenomenal world and thus add to human suffering.

Among orthodox Hindus the six darshana or philosophical systems based on the Vedas eventually came to dominate Hinduism and, under the influence of Buddhism, took its most radical form in the non-dualist (Advaita) Vedanta of Shankara (eighth century CE). Vedanta was associated with the Mimamsa devoted to textual interpretation of the Vedas. Like Buddhism, Advaita Vedanta held that the "enlightened" souls come to understand that the phenomenal universe is illusory and are thereby freed from transmigration. Hence any further cosmological speculation is seen to be vain. Thus Shankara rejected the Samkhya-Yoga systems and the Nyaya-Vaisesika systems that had provided two types of speculative cosmology that parallel Greek natural philosophy. [85]

The cosmology of the Samkhya-Yoga system had deep roots in the Upanishads but was attributed to a sage named Kapila (500's BCE) whose works are lost. It was given its systematic form by Panini (fl c. 140 BCE). Samkhya teaches a dualism of matter (Prakriti) and spirit (Purusha). Spirit is said to be "the silent witness of change" and hence is not an efficient, but an exemplary formal cause of the universe. It is also its final cause since matter has an internal, teleological tendency to evolve in order to more perfectly imitate Spirit. Matter is substantial and possesses three intertwining qualities called gunas: sattva (from sat, the real or existent), rajas (from raj, motion or energy), and tamas (darkness or inertia). When these qualities are in balance the universe is in a quiescent and undifferentiated phase (pralaya), but it becomes active and differentiated when the presence of Spirit so arouses the quality of rajas that it overcomes the resistance of tamas and results in the dominance of sattva. Thus matter becomes more and more like Spirit, never however, becoming identical with it.

This process of differentiation of Matter first produces Cosmic Intelligence that then divides into an individual self-consciousness proper to each person. In each personal self a further differentiation takes place between Mind (manas, seemingly equivalent to the Aristotleian "internal senses") and the five external senses with their subtle objects. These objects are sound, the tangible, the visible, the flavored, and the odorous, to which correspond the sensible elements: ether, fire, water, earth that carries sound, and air that carries sound and touch. These are in turn paralleled by the five physical operations of speaking, procreating, excreting, grasping, and moving. Thus cosmic and individual intelligence and mind are all included in Matter and only when Spirit is emancipated from reincarnation in Matter in all its differentiations does it at last exist in its purity as the solitary Absolute. Samkhya, however, says nothing of a creator God. The Yoga system accepts the Samkhya cosmology except that it adds to it a creator (Ishvara) as an efficient cause of the differentiation of Matter. Yoga, however is mainly devoted to the meditation techniques by which this separation of spirit from matter is to be effected.

The Nyaya-Vaishesika pair of systems was attributed to Kanada (c. 200's BCE) but its standard systematization dates from about 300 CE. The name Vaishesika means "property" or "peculiarity" and indicates the realistic and pluralistic character of this system. It distinguishes a set of categories that includes substance (dravya), quality (guna) action (karma), and relation (samavaya, connectedness), plus the logical categories of genus and species. Latter abhava, non-existence, was added to this list and perhaps refers to what Aristotle meant by purely mental beings (entia rationis). The Category of Substance was subdivided into (1) earth, (2) water, (3) fire, (4) air, (5) ether, (6) time, (7) space, (8) soul (atman), and (9) mind (manas). The first four kinds of these substances consist in atoms too small to be visible, although three atoms taken together make extension (quantity). Soul and mind (internal senses) form the individual human being. Again, as in Samkhya-Yoga, release from reincarnation is to be gained when a self (atman) realizes it is independent of the material body. Vaishesika like Samkhya was originally atheistic, but later, like Yoga, it added a creator God to produce this plurality of substances. Thus in both cases Ishvara or God is not really a creator ex nihilo in the Judaic sense, but resembles the Platonic "Demiurge" that is only the efficient cause of the origin of plurality and differentiation of preexistent matter.

Thus Samkhya and Vaishesika have many points in common with Greek cosmology. Samkhya resembles Platonism in positing an ascending scale of being from gross matter to subtle matter in imitation of Spirit as the exemplary and final cause but not the efficient cause of cosmic change. Only in this way does it seem to Samkhya and to Platonism that it is possible to save the First Principle of change from being itself subject to change. On the other hand Vaishesika resembles Aristotelianism in its pluralism and its careful development of categories that are similar to, though not entirely the same as, Aristotle's categories. Thus for Vaishesika "aether" is not, as for Aristotle, the matter of the inalterable celestial bodies, but fills all of empty space and thus more resembles the aether of nineteenth century physics. The same is true in Vaishesika of "time" and "space" that are more like substances than Aristotle's relational accidents of "time' and "place."

It would seem, therefore, that the Samkhya and Vaisesika cosmologies, and also the still less developed one of Jainism, belong more to the level of pre-Socratic thought (for example, in their concept of atoms) and of Platonism than the critical Aristotelian physics out of which modern science ultimately developed. Three factors seem to account for this. First the primary interest of Hinduism is not to study of nature as such but rather to emancipate the human spirit from a world of change and suffering. Second, the reliance of these cosmologies on the Vedas as a record of spiritual experience accessible to all who strive to attain it, perhaps made these philosophers too easily content with their analyses of sensible experience. Third, the Greeks' development of pure mathematics and, as a result, their systematization of a more critical logic of science stimulated them to go beyond the level of cosmology that Indian achieved.

The philosophies of China and its satellites in Korea and Japan can be more briefly noted because China, although it had a rich ethical tradition was much less concerned about "metaphysical" questions than the West or India. [86] The central figure was Confucius (K'ung Fu-Tzu, 551-479 BCE) who in Chapter I was mentioned among the world religious reformers. He reverenced the traditional High God of China (Ti'en or Ti or Shang-Ti, Lord) by the impersonal name of "Heaven," but discouraged speculation about the spiritual realm. His chief concern was to form personal character through education so as to promote social harmony. This education was served by the careful practice of traditional rituals and etiquette and by the study of the Five Classics of Chinese literature. Confucianism was developed with an optimistic attitude toward human nature by Mencius (c. 372- c. 298 BCE) and with a more negative attitude by Hsün- Zu (c. 313-c.238 BCE). Under the Han Dynasty in 136 BCE Confucianism became the official state philosophy or religion in 136 BC and the basis of education.

As the thought of Plato dominated the West yet was always under criticism by the Aristotelians, so Confucianism was constantly criticized by the Daoists (Taoists). The origin of Daoism was attributed to Lao-Tzu, a contemporary of Confucius and developed by Chuang-tzu (born 389 BCE). In opposition to Confucian emphasis on education the Daoists favored a search for a harmony between human life and the rhythms of nature and were not adverse to the practice of astrology and various magical efforts to achieve physical immortality. Thus throughout Chinese history this dialogue between the social traditionalism of Confucianism and the nature mysticism of Daoism kept each other in balance.

Related to these two principle tendencies were on the one hand the Legalism of Lord Shang (d. 360) that sought social order by the enforcement of laws in contrast to Confucius' emphasis on the development of personal virtue, and Mohism. The latter was named after Mo-Tzu (409-403) BCE) and tended in the Daoist direction. Yet Mohism also developed a remarkable system of logic, or more accurately semiotics, an interest already expressed by Confucius when he said that that great attention should be given to the correcting naming of things, since to name is find the essence of a thing. This elaborate study of language and dialectics, often called the School of Names, was used by Mo-Tzu to support a utilitarian ethics and with Chuang Tzu (c. 360) led to what has been called a "skeptical perspectivism" that urged the toleration and reconciliation of many points of view. [87]

In this classical period there was also some interest in understanding the natural order by the so-called Yin-Yang School, but mainly as the pattern for ethical harmony. These thinkers sought to explain the world as a balance between active, masculine agency (Yang) and feminine passive receptivity (Yin) acting on five material principles, fire, wood, earth, metal, and water. This roughly parallels the Indian Samkhya and Vaishesika cosmologies as well as the Greek notions of matter and form, the four causes and the four elements. Nevertheless, Chinese cosmologists seems to have regarded the world as pluralistic, "ten thousand things," rather than as a systematic whole. They did not seek to explain the world through causes much as to relate things by their similarities.

Thus Chinese logic was really more a semiotic or hermeneutic than a system of demonstration. Nor did Chinese thinkers focus on metaphysical Being v. Not Being, as did the Greeks from Parmenides on, but rather on the you vs. the wu, terms that are translated as "availability" or "possession" vs. "unavailability" or "non-possession" in the sense of the presence or absence of some object as significant for practical decision and action.

During the Han Dynasty official Confucianism attempted to assimilate the other tendencies of Chinese thought to form a unified synthesis. In the first century CE, however, this synthesis was somewhat eclipsed by the influx of Buddhism from India and later through the mission of the Buddhist sage, Boddhiharma (475 CE). This Chinese Buddhism, however, was soon modified by Chinese practicality and took on the form of Ch'an (Japanese Zen). In this current the T'ien Tai (Japanese Tendai) sect, led by Chih-i (538-597), developed a system of the "Perfectly Harmonious Three Fold Truth" based on the Lotus Sutra. This Chinese interpretation of Buddhism teaches that although the phenomenal world is "empty' or "non-existent" yet it also has a true temporary existence that is simultaneous with its non-existence. Hence by the practice of constant silent mediation Zen hopes to maintain this sense of emptiness in the midst of daily, practical life without opposing one to the other. In this way the practical Chinese could accept Buddhism without rejecting their pragmatic orientation.

Buddhist influence declined in the ninth century BCE when under the Song Dynasty (993-1059) a Neo-Confucian ethics recovered dominance. Yet the more speculative and metaphysical questions that Buddhism has raised demanded to be assimilated to the Confucian perspective. Chu Shi (1130-1200) founded what is called the School of Principle that in the fourteenth century became the official interpretation of Confucianism. It taught that all things are explicable by li ("Principle") that reflects a supreme principle, the Great Ultimate (Daji) and by qi (matter) that is given order by li.. The ethical conclusion of this dualistic systematization was that persons must imitate li in themselves and their lives so as to control the disorderly impulses of their bodies as physical matter.

In opposition to this dualism the School of Mind led by Ch'eng I (1033-1107 and Chu Shi (1130-1200) taught that li or Principle was innately free of matter so that everyone could discover the truth by which their lives could be guided by looking within themselves. Eventually this idealist school adopted Ch'an meditative practices or returned to a Daoist reliance on spontaneous instinct. Thus Neo-Confucianism experienced a debate between Realism and Idealism parallel to that in Western thought. With the Manchu Dynasty (1644) a School of Practical Learning arose in opposition to idealism and subjectivism culminating in the writings of Tai Chen in the eighteenth century. He insisted on the importance of a positivistic concern for facts and consequences in making ethical decision. This positivistic Confucianism was soon confronted by western thought and modern science and at the beginning of the twentieth century China fell under the influence of the western Marxism that still dominates the country although this too is undergoing adaptations to the native culture.

Even this brief comparison of the highly spiritual culture of India and the practical, ethical culture of China reveals many parallels between their worldviews and those of the Western Ecumene. It is also, clear, however, that the Western achievements in natural science, the metaphysics that they imply, and the increasing control over nature by modern technology that science makes possible were never fostered in these two great cultural centers. Nevertheless as the West has come into contact with Indian spirituality and the more practical ethical and social wisdom of China, it has begun to see its own limitations and to find in these two cultures an inspiration to recover spiritual and ethical elements in its own tradition that modernism neglected. Centers for the study and practice of "Eastern Spirituality" are springing up throughout the United States and Europe.

This opening of the West to the East proclaims to modern science how necessary it is to face the problem of the seeming dualism between matter and spiritual intelligence that today's science still attempts to ignore. From an Aristotelian perspective, on the other hand, it is clear that Eastern cultures as they accept western technology must now deal with the modern science that developed out of Greek cosmology. Yet in doing so these non-Western peoples must critically rethink the foundations of modern science so as not to succumb to its materialism and reductionism. A tragic aspect of the confrontation of East and West is that Western technological dominance may undermine this ancient wisdom before it has had the opportunity to make its full contribution to humanity. A western scholar who has studied the traditional schools of India in which this wisdom has been handed on through the centuries found them dying. [88]

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[1] Joseph Silk, The Big Bang, rev. ed. ((New York: W. H. Freeman, 1989).

[2] Vincent Edward Smith, The