According to http://www.informationphilosopher.com/freedom/history/ Kant believed in both determinism and rational thought.

Kant subsumed causality and determinism under his idea of Pure Reason. Indeed he made determinism a precondition for rational thought.

This is interesting to me, as it would seem that without an ability to freely choose between alternative explanations according to which seems more reasonable, rational thought is undermined.

I am trying to work my way through portions of Critique of Pure Reason, but I am having trouble getting my head around it.

Can anyone explain Kant's view that rationality and determinism are compatible, if the above quote indeed does reflect Kant's view? If it is somehow incorrect, can anyone explain what he actually held to be the case?

  • See my answer here philosophy.stackexchange.com/a/31834/1547 Jan 30, 2016 at 18:35
  • " without an ability to freely choose between alternative explanations according to which seems more reasonable, rational thought is undermined" We don't choose the result of applying reason. The propositions follow from one another, to an inévitable conclusion which is the correct one, lest we make an error (which is not voluntary, if we want to be reasonable). When redemonstrating the pythagorean theorem, nobody chooses to conclude that the square of the hypothenuse is the sum of the squares of the other sides: it is the only possible conclusion.
    – armand
    Jan 26, 2021 at 11:08

2 Answers 2


Put most simply, Kant falls back on the Augustinian notion that determinism and free will are both real, because time is an illusion.

For Kant, time and space are forms of human intuition, and other beings are not necessarily bound by them. Our notion of causation is tied to time, but in a lot of ways, traditional religion expresses divine or angelic causation as tied to intention alone. To use Aristotle roughly, final cause is ultimately more real than efficient cause, and efficient cause may exist only for animals.

If a use helps -- this idea helps to nail down some aspects of how, for instance, maxims must be universalizable. Intention is allowed as a real parameter, but time should only be a contingency. A categorical decision that involves a time limit cannot really be truly categorical, because causation is the category and causation is not necessarily temporal succession under natural law -- that is just how it looks to us.

  • I see, so Kant is not referring to determinism in the modern secular sense but in the Augustinian. That clarifies things.
    – Jason Bray
    Jan 5, 2015 at 19:24
  • I am not sure what you mean by that. They pretty much correspond. I guess there is a sense in the religious version of the disposition of will, which plays itself out in time: your decisions are determined, but what determines them is some eternal 'you' which is in a different sense expressed by and made up of your decisions.
    – user9166
    Jan 5, 2015 at 20:15
  • Well, I'm not sure this is the place for it, but my understanding is as follows: In a secular hard determinist sense, "you" don't do anything. All decisions are determined by interactions of chemicals and physics. The idea of free will is non-existent. The way I understand Augustine is that you choose in a sense logically prior to the beginning of the universe. Things play out in one and only one way, but your decision is part of what determined that one and only way to begin with.
    – Jason Bray
    Jan 5, 2015 at 20:34
  • I think we are saying the same thing. Given this distinction maybe Kant would say what you are calling 'secular' is 'phenomenal', and in a 'phenomenal' sense 'hard determinism' is quite true. But there is an underlying 'noumenal' sense of intention within the parameters of expression, which accounts for our sense of freedom. Both are true, but the version including 'eternal intent' is 'truer', even if it cannot be captured correctly in language.
    – user9166
    Jan 5, 2015 at 20:53

The quote you've got there is basically wrong.

A more correct thing to say would be that Kant believes the physical world is determined, but that rationally we are free. Or to put it another way, on the phenomenal level, all actions are determined in accordances with the laws of nature (we might in modern parlance says the laws of physics). But we need freedom in order to have moral responsibility. Thus, we are both free and determined at the same time. (This is the third antinomy).

I don't read the "refutation of idealism" the way jobermark is suggesting, which is a minority reading among Kant scholars. Instead, the section shows that time and space are not just inner conditions of my experience, but real conditions of my experience, because they occur in a way that conditions my experience before I bring to it my rational apparatus.

A key thing to keep in mind is that Kant is a skeptic about the potential for knowledge of things as they are. Conversely, he thinks we can engage in acts of understanding towards objects and perception of sensibles as we bring these under the categories of understanding and forms of sensibility respectively.

But it turns out freedom of the will is no such thing, and thus we cannot know it nor can we understand it through our categories. But we do in fact use it and have it. Thus, we are left in apparent contradiction that neither understanding nor reason can settle. As Kant will explain in his moral philosophy, we are in fact free but noumenally free. Meaning on the level of phenomena, all of our actions are determined, but at the level of will and rational action we are in fact free.

This might work out to the freedom outside of time that jobermark mentions. But I'm not sure I understand what he's saying there. Because he seems to be saying that this is freedom outside of time in the sense of having been chosen from before eternity -- but I take it to be outside of phenomenal time -- meaning it occurs in a way that is beyond our observation, even our observation of ourself. But the reason for this in Kant's picture is that we are limited to what pure reason determines we can know. And we can only know objects, and freedom is not an object. Ergo, if it occurs in time, we can never witness it. But through reason that we have freedom.

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