Immanuel Kant’s philosophical theory is the direct result of Rene Descartes, and the philosophical ancestor of Nietzsche. Kant relegated God, human free-will, and the immortality of the soul to the realm of the noumena, beyond our access; however, he didn’t feel comfortable getting rid of these ideas altogether. As his Critique of Practical Reason shows, he felt that it was necessary to bring these concepts back as the ground of morality, though we still cannot know that they really exist. However, once placed out of our reach, it is not so big of a stretch to denying their existence altogether. Bringing them back as the foundation of a system of morals seems to be somewhat gratuitous. If we cannot know that God exists, and if his existence does not have any impact on the world of our sense impressions, then it seems unnecessary to postulate that he does exist. For all intents and purposes, we might as well deny not only knowledge of God, but his existence all together.
A Critique of Kant
This being said, we are not obligated to agree with Kant that the direct object of the understanding is the intuition as synthesized with the concept. To agree with Kant, and by consequent with Descartes, is to guarantee the same conclusions. Rather, as a preliminary critique of Kant, it must be noted that if we have no direct access to the real world, the mind-exterior and mind-independent world, but are entirely at the mercy of our sense impressions, then, not only can we not know that God exists, but we cannot even know that there is a mind-exterior world. How can we know that our sense data corresponds to the mind-exterior reality, what actually exists, unless we have direct access to mind-exterior reality?
In order to know that our intuitions are actually representing something, we have to be able to get past them, to that something, so as to compare the something with the intuition. However, Kant can’t do this; so, he must be skeptical, not just about God, immortality and free will, but also about all of the phenomenal world, all of his sense impressions. Without sense impressions, he is only left with the “blind” concepts of the understanding, without knowledge, and therefore, in absolute skepticism. He does not, therefore, have anything to offer us, and the system that he set up in order to preserve, and allow for, scientific inquiry, ends up removing the possibility of experimenting with anything outside of our minds.
Secondly, a further critique of Kant’s system is based upon the fact that he relegates God, the immortality of the soul, and human free-will to the noumenal world. Though he wishes to keep God around, he has no basis for it, as he has already claimed that we have no sense impressions of God, and that we don’t have the form of God in the a priori conceptions. Though he thinks that free-will is necessary for ethics, he has already eliminated any possibility for it, in the same way that he eliminated God. Many scholars think that his reintroduction of God and free-will, as a basis for ethics, is gratuitous and unnecessary. As many of his followers were inclined to observe, there is no reason to bring these concepts back into the picture, rather, it is easier to just deny their existence altogether and to continue on from there. As such, Atheism and determinism, and in fact, the basic Naturalistic worldview, becomes an immediate heir to Kant’s throne. There is no God, no need for man to have a soul, free-will, or immortality, and no need for any immaterial entities. After all, we cannot observe these things; they are not presented to us by our sense impressions, as Hume showed they are just imposed on reality due to unfounded traditions. Furthermore they are not necessary, according to Kant, for the scientific methods which were so dear to Kant. Why, then, keep them around?
If it is true that there is no soul, and no human freedom, then the phenomenon of reason must be explained away as a by-product of physical, or materialistic, processes in the brain. Therefore, reasoning, which seems to be an immaterial process, is explained away. However, if reasoning is explained away then so is Kant’s theory, which he arrived at through the reasoning process, as well as the theories of his followers. Kant, therefore, in attempting to explain how it is that man “reasons”, has explained it away, and arrives, inevitably at the Nihilism of Nietzsche.
The Knowability of God
The conclusions of Kant’s philosophical endeavor, can, however, be avoided. In order to avoid these conclusions, we must have a different point of departure. Rather than making the idea the direct object of the human knower, we must have direct access to the mind-exterior and mind-independent reality. If we have such direct access, then, as Etienne Gilson has observed, not only do we get the world, but we also get our knowledge of it, ourselves, other minds, and our own thoughts, among other things. In fact, if we have direct access to a mind exterior reality, then we can also have knowledge of the existence of God.
Contrary to the claims of the many of the great modern philosophers, and especially Kant, the existence of God can be deduced from the existence of a mind-exterior, mind-independent, reality. As Aquinas points out in the Summa Theologiae, the fact that we observe change (motion) in the world, points to the existence of God, the first unmoved mover. Aquinas demonstrates that this is due to the fact that whatever is in motion was put in motion by another (any change was caused by a changer). Change is not possible unless, first of all, the thing changed is in potential to the change which is brought about. This is because, change is what happens when one of the potentialities of a thing that is actual, with differing potentialities, is made to be actual. Yet no one thing can at the same time be in act and in potency in regard to the same thing, therefore, the actualizing of its potential must have been done by another. If the mover was moved from act to potency, then the same principle applies to it, as to the thing that it moved, and so on, it would seem, to infinity. However, it is impossible that there be an infinite regress of changing changers actuating the potencies of other changing changers, because if such were the case there would be no first change, but without a first change there could be no further changes. Therefore, there must be some unchangeable changer, and as Aquinas says, this is what everyone refers to as God. Therefore, based upon empirical knowledge of reality, we can, by deductive reasoning, know that God exists.
Therefore, not only is it possible to know that God exists, but, if we have direct access to mind-exterior, mind-independent reality, we can engage in scientific research and discovery. Therefore, in this way, we also allow for the natural sciences, which was Kant’s principle worry.
Both Aristotle and Thomas Aquinas claimed that intellection was an immaterial process not connected to any physical organ. Cf. Thomas Aquinas, Commentary on Aristotle’s De Anima, trans. Kenelm Foster and Silvester Humphries, 2nd ed. (Notre Dame, IN: Dumb Ox Books, 1994), 7-12.