An antinomy of reason is an irresolvable logical contradiction. In the case of freedom, there has been an age-old dispute between two positions on the subject of human freedom: (1) humans have unfettered free will; (2) human decision-makuiufging is deterministic like the rest of nature. The former position carries more sentimental weight because it makes ethics possible and because people intuitively believe they are free actors. The latter carries more scientific evidence because, as noted, it corresponds with the rest of nature. If our bodies are subject to cause and effects, why shouldn’t our minds be so, as well?
We cannot deductively verify either claim. For every decision that the former party says is a free choice, the latter provides a list of reasons it was a simple case of cause and effect. Certainly, we cannot give scientific evidence that we have free will; neurology seems to make that prospect more remote with each passing year. Yet intuition and even the conventions of our language tell us that we make our own decisions. Furthermore, there must have been some spontaneous first cause for everything, or else the chain of cause and effect would stretch back an infinite amount of time, into absurdity. This spontaneity implies the existence of another rule, besides causality: freedom.
Each side of this debate assumes that free will and causality contradict each other. Kant rejects this assumption. He argues that the laws of nature apply only to spatiotemporal events while freedom is a category of reason, which is free of space and time. Since freedom, by definition, is non-temporal, we use it to make a priori judgments which are free of experience. Because we are objects, our bodies can still be subject to causality qua the laws of nature, whereas as rational agents, our minds are free of it. Our minds, if free, can be first causes, themselves, determining actions but not determinable by them.
Kant characterizes freedom as a thing-in-itself, like God and the soul. We can postulate its existence, and we can believe in it, but we cannot understand it. Because this is a world of deterministic natural laws, we cannot comprehend how or why we have this freedom to use our rational faculties however we please. We simply do, and because that power does not come from this world, it does not conflict with determinism.
This position is consistent with Kant’s contention that we can’t know whether or not we are free. Kant has proposed to divide the person into two parts: the physical part which is dependent on the laws of nature and the rational part which has freedom from those laws. He acknowledges, however, that proposing an un-analyzable thing-in-itself such as freedom is a double-edged sword. Because it exists outside the veil of perception, in a noumenal dimension, it can neither be proven false nor proven true. Our scientific proofs are entirely dependent on our perceptions, and freedom lies outside these. Our rational proofs are merely inductive because determinists can provide a plausible counter-argument that any apparently free decision was actually determined. (Tolstoy did so in the last book of War and Peace when he says that every decision we make is simply the easiest one available – in other words, we follow the path of least resistance.)
If determinists continue to scoff at the idea of freedom, however, Kant can simply refer them to Hume’s treatise against causality. Because the law of cause and effect is a child of the categories, it carries the same ontological status as freedom. While it is true that we do not know whether people have free will, it is also true that we do not know for certain whether the law of cause and effect will continue functioning tomorrow. We have inductive, not deductive, evidence for both. As Kant said, we must deny our presumptions of knowledge to make room for belief.
To prove that he is a thinking substance, Descartes employs the “evil deceiver” thought experiment: our senses tell us that we are physical beings. We have bodies, and our bodies interact normally with other physical substances. However, an all-powerful evil deceiver might be fabricating all our sensory experiences. If he is, then our bodies and the outside world do not actually exist, and we would have no way of knowing it because we cannot see anything beyond our sense perceptions. Even if our bodies are illusions, however, our minds cannot be because we continuously exercise free thought. Because I have self-awareness, I must exist. There must be something for the evil deceiver to deceive, and I am that thing.
So, I have confirmed my mind’s existence. Since the deceiver has deceived me, I must be something, and that thing is a thinking substance: res cogitans. Because I cannot prove the existence of my body, it must be separate and distinct from my mind. Therefore, I have two natures, mental substance and bodily substance (res extensa), but I exist primarily as a mental substance.
Kant agrees that the “evil deceiver” doubt proves that I exist, but he argues that it does not prove that I exist as a substance. A substance is a being with independent existence. I have plenty of empirical evidence that physical objects like books, wax, and my body have independent existence (at least according to the laws of the world I perceive), but I do not have enough sensory experience to prove the same for my mind. My mind may only be a property which is dependent on some other being for its existence. Perhaps I am a figment of the dreams of Brahma, a property of his imagination, and when he awakes from his sleep, I will cease to exist. Since I have no recollection of my mind living independently, I can make a strong argument that my mind is simply a very active property of my body. When my body dies, my body will lose the property of my mind, and my consciousness will vanish. I cannot prove this is true, but by the same token, Descartes cannot prove that it is not true, so his statement that I am a res cogitans is an unfounded assertion.
The goal of Descartes’s meditation is to prove us certain, or deductive, proof of certain metaphysical truths. One of the things which he believes he has deductively proved is the existence of an immaterial thinking substance (also known as the mind or soul). I cannot see, hear, or feel a “thinking substance.” This substance, however, is inaccessible by our empirical experience. I cannot see it or feel it. I cannot even define it in coherent terms: the definition of a thinking substance is “a substance which is not physical,” but every substance we encounter is physical, so this is nothing but an incomprehensible negation. According to Kant, anything which we believe exists, but which we cannot understand because of the limits of our perception, is a “thing in itself.” Since Descartes claims we can have knowledge of the soul, but yet the soul is something we cannot access with our perceptions, he is claiming we can have knowledge of a thing in itself.
Descartes makes an ontological argument for the existence of God in the fifth meditation. He first says that he has a “clear and distinct” idea of God. If an idea is clear and distinct, it must be legitimate, unlike purported ideas of incomprehensible things like round squares. The God which He has perceived is perfect in every possible way. One of the possible traits that a thing can have is existence. In this category, existence is perfect while non-existence is imperfect. Because Descartes’s God is perfect in every possible way, his God is also perfect in the trait of existence: in other words, He exists. It is logically impossible for him to not exist.
Kant argues that no concept stipulates its own existence; rather, it expresses a possible thing or state of affairs. In this sense, the concept of a dog is equivalent to the concept of a unicorn. A real predicate is one which contributes information about that concept. For example, the statements “dogs are quadrupeds” and “unicorns are pure” express facets of these beasts which are intrinsic to their definitions.
Existence stands on a completely separate plane. Every existence claim is synthetic, not analytic, so existence itself cannot be a “real predicate”. If dogs became extinct, our concept of a dog would not change, but if we removed the “quadruped” property from our concept of dog, we would have a completely different concept. No concept can guarantee its own existence, not even a concept of a perfect God.
I believe that Kant’s claim successfully undermines Descartes’s ontological argument. Even if his analysis of the property of existence is wrong, his objection is enough to throw Descartes’s argument into doubt because it draws a clear distinction between concepts and reality. Concepts and reality and fundamentally different, and I can deny the reality of a concept no matter what stipulations the concept makes about itself. If there were a concept “A” with the condition “you must necessarily believe in A,” would I be required to believe in A for this reason? That would be absurd. Why should concepts and reality be so intricately linked, and why would the idea of God be an exception to this rule?
Descartes says that God is an exception because unlike all his other ideas, his idea of God is innate. The ontological argument is merely Descartes’s second case for God; his first was his claim that his idea of God is both innate and “clear and distinct.” He says it is not some muddled fancy; rather, it is a thought as real as or even more real than his sensory perceptions. Descartes reasons that if one has an idea of something, one must have experienced something like it before. Even chimerical beasts such as unicorns are amalgamations of previously experienced objects. Yet Descartes’s God is something the philosopher has not experienced in the real world. He has not even experienced something with a single perfect trait. How, then, could it be possible that he has ideas of God and perfection? Descartes reasons that if he has not received his idea of God from experience, it must be innate. God must have put the idea there, and it must have always lived inside him. In this manner, he would shrug off Kant’s quibbles about the nature of existence.
Kant can address this proposition in the same way he addressed the matter of freedom. He can say that Descartes’s intuition is sufficient grounds for his belief in God, but it does not justify his claim of knowledge. It is possible that Descartes is either lying or hallucinating; David Hume, for instance, thought it was the latter because neither he nor anyone he knew had these “clear and distinct” perceptions, themselves. God is ultimately a thing-in-Himself. He does not reveal Himself to our sensory perceptions, and as Descartes said, His properties (omnipotence, omniscience, and so forth) are the kind which are impossible to imagine in this world. Regardless of what Descartes thinks, the idea of God is incomprehensible to us, locked as we are in our world of sensory perceptions. Emotion is not evidence.
Kant says that the claim “God is a substance” is analytic, but it does not assume God’s existence. This is because analytic judgments are analyses of the facts which are contained inside concepts, and physical existence is not a necessary condition for concepts. Yes, we have concepts of existent beings, such as dogs, cats, and bachelors, but we also have concepts of non-existent beings like unicorns and witches and abstract entities like justice, freedom, and power. Superman does not exist, but that doesn’t stop his fans from arguing about the extent of his powers. (For instance, I think it was absurd that he moved back in time by spinning the world backwards in the first Christopher Reeve movie.) Each fan has a concept of Superman, and they make different analytic judgments of what he can and cannot do based on that concept. Likewise, it’s impossible to show someone what justice is, but we all have different concepts of it, so we are always debating about what is just.
We cannot know that God exists, but we all have concepts of God. When Kant says that “God is a substance” is an analytic judgment, he is saying that the predicate “is a substance” is part of the definition of the concept “God.” God does not necessarily exist, but if He did, He would be a substance. Kant is merely defining his terms. It’s the logical equivalent of saying that a bachelor is unmarried, or that unicorns are pure, or that Superman has X-ray vision. We can accept that a triangle must have three sides while denying that any triangles exist.