In chapter 3 of his work "A Survey of Christian Epistemology", Van Til examines the revolution in Greek thought in the work of Plato. He notes that part of what makes Plato's work so revolutionary is that before him, the Presocratic philosophers were primarily monistic materialists. It is only with Plato that we start to see the development of an ontological dualism between mind and matter. Van Til describes this development poignantly:
The true nature of man is his soul, and not his body. A dualism is developing. Moreover, the true nature of man is the intellect and not the senses. Only through the intellect can man come into contact with the universals, and these universal Ideas have more reality than the particulars of sense experience. Another dualism is developing. The true function of man’s soul is contemplation of the Ideas, and its highest destiny is separation from the world of sense in order to be wholly absorbed in the contemplation of Ideas(Van Til).
Nevertheless, Van Til sees in this element of Plato's thought what he refers to as a tendency towards abstraction or depersonalization:
In the second place it should be remarked that Greek philosophy as a whole tends to depersonalization and abstraction. Not as though this was consciously the case. It could not have been done consciously because the modern concept of personality was unknown to the Greeks. What is meant is that though there was in the instance of Plato an advance from materiality to spirituality this was itself abstractly understood. One aspect of the universe is thought of as material and the other aspect is thought of as spiritual, and the soul finds its home in the spiritual aspect. But of this spiritual aspect of the universe, the soul is at most an individuation(Van Til).
He argues likewise that Plato's thought exhibits tendencies which he believes characterize all non-Christian thought:
1) Depersonalization and abstraction
2) An identification of the person with the laws of the universe
While Plato argued that knowledge had to be knowledge of universals rather than particulars, he did admit (via Socrates), Van Til notes, that a learning stage, presumably in which one were to some degree dependent upon sense, had to precede the acquisition of universals which constituted true learning. The human comes to true knowledge through intellectual contact with the Ideal world rather than through the senses.
Van Til notes that perhaps what distinguishes Greek thought from Christian thought most radically is the apparent lack of need in Greek thought for a mediator between God and man. Neither the soul nor the body needs to be reconciled with the divine; or, Van Til suggests, if some sort of reconciliation is indeed necessary, it is solely a reconciliation of the human mind to the divine world of Ideas, and this does not involve a reconciliation of the body. The manner in which Platonic thought would influence the later Gnostic hostility towards the body is obvious here.
Even in Plato’s maturest thought as expressed in the Timaeus, there is only a faintest suggestion of the idea that it is perhaps the soul’s function to bring together two opposing forces in the universe, namely, spirit and matter. And this lack of any notion of reconciliation that at all approaches the Christian idea on that subject corroborates what was said above about the assumption on the part of the Greeks, that the mind of man is naturally sound. It is assumed that there is no reconciliation to be made between God and man. And if there is any reconciliation to be made at all, it is the mind of man that is to do the reconciling. Thus the mind of man does not need any reconciliation to God by God, but it can itself reconcile the physical universe to God. Instead of needing a Mediator, the mind of man sets itself up as mediator if there is to be any mediator at all(Van Til).
What is of interest to the Christian is Plato's belief that the soul is immortal, and his arguments for this belief. For Plato, all soul is self-moved and anything that is self-moved is immortal. The human soul is inseparably bound up with the cosmos which is itself eternal. It is Plato's understanding of the relation between time and eternity, and the lack of derivation of either from the other, that makes his metaphysics particularly incompatible with that of Christian theism:
It is of particular importance here to observe that the final basis of the argument is the assumed eternity or at least endlessness of the existence of the universe. Plato nowhere identifies time and eternity, but he does the next thing to it. For all practical purposes his conception of time as “the moving image of eternity” amounts to saying that the eternal and the temporal are equally ultimate aspects of one general Reality. When we say “ultimate” here we do not mean that the temporal and the eternal were equally valuable in the eyes of Plato. Quite the opposite is the case. The eternal is sometimes presented as being the only valuable aspect of reality. But this does not change the fact that, according to Plato, time and eternity are equally underived. Eternity is not derived from time, but neither is time derived from eternity. And this is the fact that makes Plato’s position once for all irreconcilable with any consistent interpretation of Christian theism(Van Til).
So from a Christian perspective, Plato's metaphysics is radically antitheistic. Christians believe that the human person is a creation of God. We do not believe, like Plato did, that humans are merely natural parts of the universe. If the human person is part of the universe, it follows that the human interpretation of the universe, Van Til points out, is no less ultimate than that of the divine mind. But for Van Til, our interpretations of reality are only legitimate to the extent that they agree with God's interpretation of the universe. This is seriously problematic for Plato from the Christian perspective, because there is no ultimate arbiter of trutrh. The divine mind's interpretation of reality is as authoritative as that of the human interpretation. Suppose there is a difference in the interpretation of some piece of data between the human and divine minds in Plato's schema. It would then follow that we would have no ultimate standard that would serve as the court of appeals for this disagreement. Yet within the Christian worldview, God is that court of appeals, and this is so precisely because He is the Creator of man, and man only knows anything to the extent that God has revealed it to Him.
Starting the argument from the other direction, we can say that the method of reasoning employed by Plato involves an independence on the part of man in order to have any meaning at all. Plato had to assume the underived character of the human mind in order to assume the underived character of the whole of the temporal universe. It really makes very little difference in this connection whether one begins with metaphysics and ends with epistemology, or whether one begins with epistemology and ends with metaphysics. The important thing to observe is that the one is involved in the other. The assumed independence of the universe as a whole leads to, and implies, an original independence on the part of the mind of man. On the other hand, the assumed independence of the human mind leads to and implies an original independence of the universe(Van Til).
For Van Til, a belief system like that of Plato's is the obvious result of the Fall. Man attemptts to become autonomous in every respect imaginable, and Plato's metaphysics is a clear attempt by man to become autonomous in the intellectual realm.
In passing, we would notice that if the Christian theistic position is true, Platonic thought is the logical development of the thought of Eve after she yielded to the temptation of the devil. Eve still had a struggle about the matter whether or not it was wise to assume the equal ultimacy of God, the devil and man. Plato no longer had any qualms of conscience on this question at all. In his time the human race had become so well accustomed to the blindness of antitheism that it took for granted that there never had been any other way of seeing, than with blind eyes. Or if this be considered too strong a statement, and someone should wish to preserve such complete naivete as we have attributed to Plato for the modern scientist, it is well. There is some reason for this. Plato was still willing to attribute some possible meaning to the myths of which the forefathers spoke. Paul Elmer More brings this out very nicely when he says that Plato begins with Rationalism and ends with theology. What he intends to convey to us is that Plato, of course, as a philosopher, begins by assuming that the human mind is capable of meeting the riddles of the universe, but that when man sees more deeply into the limitations of human thought he is willing to listen with some respect to those who claim to have had revelations from the gods. Plato regarded the myths of an original golden era as of only secondary importance, as something to which one might listen after one’s own efforts at solution have failed. There might possibly be something to these myths after all. The modern scientist, on the other hand, would of course not so much as listen to the Genesis narrative of man’s original contact with God. In this respect Plato was less extremely antitheistic than the modern scientist. Even so, the distance between Eve and Plato was greater than the distance between Plato and the modern scientist. Plato had reached the stage where antitheistic assumptions were already so deeply ingrained in the human race, that no man of any intelligence questioned them any more(Van Til).
But in what way does Plato believe that man is an organic part of the universe? He argues in his Phaedo as well as the "Meno" that the soul partakes of the idea of "Life." The soul is immortal in light of its co-ordinate, equiprimordial existence alongside the Ideas, of which it participates in this temporal life. Van Til notes that in order to understand this view we must understand how Plato understood the relation of the soul to change. He argues that the soul was initially understood, in Greek thought, as a kind of "principle of movement" rather than consciousness. This is unsurprising, in light of what Van Til has taught us about the monistic materialism which was characteristic of Presocratic thought. Instead of being thought of as a principle of change, the soul, in Plato's thought, is contemplated as being derived from principles of eternal Ideas.
The Idea of life partakes of the general characteristics of all Ideas, namely, that it is eternal and self-existent. Now of this Idea of life the soul is a concrete manifestation or particularization. The soul “participates” in the Idea of life and is therefore underived. Thus far the argument is that with which we have grown familiar from the previous considerations. The new element added is that the notion of change is taken right into the realm of Ideas. The whole temporal world is conceived as no more than a concrete particularization of the eternal world. Instead of being a creature in a temporal world created by an eternal God, man is made the joint creator with God of the temporal world. But even this does not express the matter with entire correctness. There is really no creation at all. There is only one universe with two aspects: the eternal and the temporal. The eternal somehow expresses itself in the temporal and it is man who goes forth as the temporal appearance of the universe(Van Til).
Van Til notes some interesting respects in which Plato has counterfeited Christian thought. Instead of the eternally preexistent, immaterial, uncreated and essentially divine Logos who becomes man incarnate, it is the eternally preexistent, immaterial, uncreated and essentially divine man who becomes incarnate! Instead of Christ being the sole Mediator on behalf of man to God, it is man who is his own mediator and savior. Contrary to the absurd notion that Christianity developed out of Platonism, Van Til gives a poignant account of the essential differences between both worldviews:
If mankind as such performs the function of Mediator, it will be impossible for any one man to be the Mediator. In the second place, for Plato eternity and time are intermixed, while for Christian theism the two natures of Christ are said to be without intermixture. The Platonic conception of the relation between eternity and time makes it forever impossible that Christianity should develop out of Platonism, as Mr. More contends that it has. The third difference lies hidden in the word “somehow.” On the surface it would appear that on this point at least Christianity and Platonism agree that both admit a final mystery in their philosophy. But this is not the case. Platonism does and Christianity does not admit a final mystery in its system. That this is a fair statement of the situation may be realized from the consideration that the controlling concept of Christianity is the concept of an absolutely self-conscious God. For such a God there could be no final mystery. When the church in effect professes that in the person of Christ the eternal and the temporal are “somehow” united, it only admits that human knowledge cannot fathom the difficulty involved. The church at the same time affirms that in God the mystery is solved. Platonism on the other hand must maintain that the divine mind as well as the human mind is surrounded with a universe which neither of the two minds has penetrated or can penetrate. Hence the mystery exists equally for God and man. If man finds himself confronted with an insoluble mystery he has no right to appeal to a higher form of intelligence for which this mystery does not exist. We shall see more fully later that here we have touched upon a fundamental difference that is bound to reappear often(Van Til)
Van Til draws a fascinating parallel between the tendency of Greek thought to arrogate intellectual autonomy and authority to man, and Paul's assumption that the Greeks would reject the Gospel. For Paul, natural man, with his fallen and unaided reason, is constitutionally incapable of believing the Gospel. It is for this reason that the Greeks would have rejected some of the most basic premises of the Gospel as fundamentally absurd. For Paul, knowledge of God only comes through God's condescending revelation, apart from which man not only cannot know anything about God, but must necessarily come to wrong conclusions about God, should he attempt to speculate about God. Obviously, for the Plato-influenced Greek mind, such notions were fundamentally absurd. Van Til notes that since the Greeks arrogated ultimate authority and autonomy to mankind in the intellectual sphere, a kind of relativism resulted which made the exclusivist nature of the Gospel totally unacceptable to them. In this respect as well, Christianity was to be seen as absurd by the Greeks.
Van Til now goes on to explain what he meant earlier when he said that he believed that antitheistic thought tends to be abstract. Contrary to this, he believes that the sort of transcendental reasoning by which only the Christian religion is able to provide the preconditions for knowledge, is comparatively concrete. Van Til describes Socrates' friends discussing with him the possibility of life after death. They review some empirical arguments for the existence of an afterlife based on inferences from the nature of things. They also consider the possibility that the soul is not dependent on the body, and so, consciousness is obliterated when the human person dies. It is only following these empirical considerations, Van Til notes, that the more abstract or non-empirical arguments for the existence of an afterlife are given consideration. It is at this point that Plato admits that the Ideal world, to which humans supposedly bear essential relation, is radically different from the temporal world. And it is at this point that Plato considers the possibility that one ought to accept the 'ancients' who had claimed direct revelation from the gods concerning the existence of an afterlife.
But now we are to observe carefully that, according to Plato, altogether different laws obtain in the eternal world of Ideas than in the temporal world of sense. In the sense world there is nothing upon which one can depend. There is no telling but that things may turn into their very opposites. There is no underlying unity that controls and gives meaning to the diversity of the sense world. There is here an ultimate plurality without an equally ultimate unity. It was for this reason that there was no guarantee to be found in empirical reasoning for the immortality of the soul. But in the world of Ideas everything is different. There nothing changes. There we seem to meet with an ultimate unity without an equally ultimate diversity. The soul which partakes of the nature of the Idea of life also partakes of the nature of the unchangeability which is characteristic of the Idea of life, as well as of all other Ideas. Hence things can never change into their opposites. More than that, things can never change at all. In the world of Ideas qualities are absolute.
To which of these two worlds, then, does the soul really belong? Surely it can not belong to both, if the qualities of the Ideal world are summed up in complete unchangeability and the qualities of the sense world are summed up in complete changeability. On the other hand it is equally certain that the soul must belong to both worlds or there would be no unity in its thought.
Plato cannot escape this difficulty and he does not wish to do so. Hence he admits in the end that it might not be so foolish after all to listen to the ancients who claimed to have a revelation of the gods on the subject(Van Til).
Plato considers the possibility that the concrete elements which we behold in the sensible and the material world somehow turn into their complete opposites. Van Til uses the analogy of ice cubes floating in water. There is some sense in which the ice is somehow essentially reducible to water, but for the moment, at least, until they melt, they remain sensibly different. Why the human soul would have left its divine realm, however, is not something which Plato is able to answer. The reason for this is that Van Til denies that Plato really believed that the Ideal world could ever exist independently of the world of sense. Neither could ultimately be subordinated to the other, whatever privilege Plato himself tended to give to the Ideal world. Indeed, the two are mutually primordial and definable in terms of one another. Van Til reminds us that for Plato, time is the "moving image" of eternity. It is difficult to imagine why Plato's Ideal world, which never changes, would cause its constituents to have sensible counterparts. Indeed, it is also difficult to imagine how the Ideal world could possibly do this at all. It seems that given Plato's understanding time and eternity in relation to the Ideal world, what we would have is a set of static incarnations. Van Til explains:
This point will be more easily understood if we recall that for Plato there is no
possible change of qualities in the Ideal world. This, if taken strictly, would mean that no change could ever take place anywhere. Theologically expressed, it would mean that creation would be impossible. The soul did not really become incarnate, but has always been incarnate in its various incarnations. Thus the sense world must always have existed in independence of the Ideal world or the two must always have existed in mutual dependence upon one another.
The same thought comes to expression if we say that for Plato the only way that time and eternity could come into contact would be by way of an intermixture. Creation or incarnation would be nothing less than essential differentiation. Plato would at one time conceive of the Ideas as immovable, so that incarnation would be impossible. Then again, seeing that incarnation was a fact notwithstanding its theoretical impossibility, he would hold that the eternal had entered into the temporal, so that there was no longer an essential difference between time and eternity. We may once more use the analogy of the ice cubes in the water. At one time Plato would maintain that the ice was the only true reality. You could kick against it and it would be immovable. Nevertheless he says that the water was also real to some extent. If the ice cubes were to maintain their reality and consequent power of resistance, they would require some friction in the medium in which they were operating. Thus it would be impossible not to ascribe some reality to the water
in which the ice cubes were floating. And then it was found that virtue is actually teachable, that there is an intermediate stage between the realm of Ideas and the realm of sense. Ice did after all seem to turn into water and water did seem to become ice. And the only explanation could be that they were at bottom constituted of the same material. It was this alone that could explain in any degree the many incarnations of the soul(Van Til)
In light of the absurdities into which we have seen Plato's thought necessarily falls, we are prepared to see what Van Til means when he says that antitheistic thought reasons in a purely abstract manner. For Van Til, abstract reasoning is
reasoning with inadequate categories. Plato tried to reason with the categories of time when he was reasoning empirically. Then he found that such reasoning could give him no information about that which he was most desirous of knowing, that is, whether Socrates should be immortal. Then he tried reasoning with the categories of eternity. But when he did that, he was unable to account for the temporal world because the categories of eternity would not move and could not create. The reason for this failure is not far to seek. Plato assumed that it was possible for man to reason with the categories of eternity. This is in the nature of the case impossible for a time-conditioned creature such as man finds himself to be. And if this is so, there are only two ways that might be followed. One might conclude that there is no knowledge possible for man at all. The time categories are certainly insufficient to explain even temporal things, let alone eternal. Hence, if he cannot reason with any but temporal categories, his knowledge is useless. The only way then for man to have any knowledge of either temporal or eternal things is for a God to think for us in eternal categories and reveal to us the Measure of truth we can fathom. Thus we hold that Christian theism is the only alternative to skepticism. But Plato in the nature of the case could not see this point. He took for granted that in the soul of man must lie the solution of the mystery of existence. He would not accept the idea that there should be a God who alone could think in eternal categories, but he believed that man could also do that which God could do(Van Til).