The Mind and Reality

Is the world of time and space ... only in the mind?

Hume's skepticism aroused Kant, Kant said, from his dogmatic slumbers. If all we can know is what we learn from experience, as the empiricists claimed, then we can't know anything about causality, or material substance, or the mind or self, or God. This radical skepticism left the house of knowledge in a shambles, and Kant saw that something had to be done. Furthermore there was the rationalists' problem of making sense of freedom in a world governed by rigid laws of cause and effect.

So first off Kant answered the problem of skepticism by observing that the only reason our sensory experience makes any sense to us is that space and time-in which all events must take place-are not "out~ there" in the world, but in the mind itself! The law of cause and effect is not a feature of the external world so much as it ig a necessary assumption we make in order that events make sense to us. Everything that happens in our world must happen in space and time, so space and time are necessary conditions for any experience at all. An object not in space and time is unthinkable. All knowledge begins with experience, as the Empiricists believed; but~not all knowledge arises out of experience, Kant said. That is, part of what we know is a priori (prior to experiences-such as that every event has a cause). As Hume said, we don't know this from experience; but Kant says we have to assume it to be true in order for our sensory experience to make sense, to hang together.

What about Locke's substratum and Berkeley's minds? We have no experience of them, that is true, for things-in-themselves and minds are by definition not knowable. Still, Kant says, we must assume that there are things-in-themselves out of which sense data arise, otherwise our sensory experience would make no sense. It would be just a jumble of sensations; and we must assume that there is a self which is free, because otherwise our moral judgments would not make sense. And what can we know about God? Nothing. For God by definition lies completely outside space and time and therefore is not within the world of our experience. The idea of God refers us beyond sense experience, to a realm where the mind cannot operate. And yet we must have faith that there is a God, although reason cannot prove His existence.

Kant calls the world of our sensory experience the "phenomenal world," and the world of things-as-they-are-in-themselves (which we can't know anything about) he calls the "noumenal world." Things we see are in the phenomenal world--trees, cars, people--and everything in that world must obey the laws of science, the law of cause and effect. Things outside that world, noumenal things-- substance, selves, God--might not. Thus the noumenal self of a person might be free from the necessity of cause and effect, even though the physical person, the body, must obey the laws of nature.

So we can't know there's a self, or causality, or a God. But we have to believe in these things anyway for the world to make sense. Kant said he wished to limit reason to make room for faith. The clergy of the 19th Century despised him in any case, for it seemed to them that he had destroyed the possibility of knowing anything about God.

The question for Kant must be: If we can't know anything about the noumenal world, how can Kant say anything about it, such as that it contains selves and material substance and God and so on? And if we drop the notion of the noumenal world, what sense does it make to talk about the phenomenal world ...?

Bibliography

Kant, Immanuel: Critique of Pure Reason, St. Martin's Press, Inc., New York, 1965.

Smith, Norman Kemp. A Commentary to Kant's-Critique of Pure Reason, Macmillan & Co,, Ltd., London, 1930.

Walsh, W.H.: "Immanuel Kant," Encyclopedia of Philosophy, Collier- Macmillan, New York, 1967, Vol. 4, pp. 305-324.

Kant, Immanuel, Critique of Pure Reason, translated by J.M.D. Meikeljohn, Londons Everyman's Library, Dutton, New York, 1934, first published in 1855.