The last two posts might feel uncomfortably close to total skepticism. “Wait,” you might say, “doesn’t this seem to imply that we don’t know anything about the real world, but only about our experiences?”

We can consider a similar claim with a similar argument, taken from Kant’s Prolegomena to Any Future Metaphysics (§52c):

If I speak of objects in time and space, I am not speaking of things in themselves (since I know nothing of them), but only of things in appearance, i.e. of experience as a distinct way of cognizing objects that is granted to human beings alone. I must not say of that which I think in space or time: that it is in itself in space and time, independent of this thought of mine; for then I would contradict myself, since space and time, together with the appearances in them, are nothing existing in themselves and outside my representations, but are themselves only ways of representing, and it is patently contradictory to say of a mere way of presenting that it also exists outside our representation. The objects of the senses therefore exist only in experience; by contrast, to grant them a self-subsistent existence of their own, without experience or prior to it, is as much as to imagine that experience is also real without experience or prior to it.

There could be a way of understanding this to say something true, but it is more easily understood as asserting something deeply erroneous. Kant may in fact have both the truth and the error in mind, or perhaps he is ambivalent concerning the correct interpretation.

Consider the distinction between the way things are known by us and the way things are in themselves. It is possible to fall into error by asserting that since things are known by us in a certain way, they must be that way in themselves. Thus we know things in a general way, and thus some Platonists might conclude that things exist in themselves in a general way, but this is an error.

But another way to fall into error would be to admit that our way of knowing is distinct from the way of being, and then to conclude from the fact that our way of knowing does not correspond precisely to the way of being, that our knowledge is false, or that we do not know at all. This is the deeply erroneous claim that Kant seems to be making above.

Consider the meaning of the statement: “We know things as they are in themselves.” If we take the phrase, “as they are in themselves,” as expressing our mode of knowing adverbially, just as we might say “We know things in general terms,” and then intend to assert that our mode of knowing is the same as the mode of the being of the thing, then the statement that we know things as they are in themselves is surely false. For the meaning would be that the things exist in our knowledge in exactly the same way as they exist in themselves — thus for example it would be implied that our knowledge is not general but particular. But more precisely, it would imply that there is no distinction whatsoever between our knowledge and the thing. In other words, if we know a horse, our knowledge is actually a horse, physically and literally. And this is manifestly false.

From this we can see both the truth and the error. The truth is that we do not know things as they are in themselves in the above sense, precisely because our knowledge is distinct from the thing known. And the error would be the conclusion that therefore we do not know things at all. Kant seems most clearly to assert the error when he says, “I am not speaking of things in themselves (since I know nothing of them), but only of things in appearance.” The Kantian may insist that this follows necessarily from the truth that we do not know things as they are in themselves in the above sense.

But it is easy to see why this is wrong. We do not know things “as they are in themselves” by having a mode of knowledge identical to the mode of their being. But this does not mean that there is anything that we do not know; in fact, having an identical mode of knowing and being would precisely mean not knowing at all, but being the thing instead. In other words, it does not follow that there is any knowledge that we are missing out on; on the contrary, knowing requires a specific mode of knowing which is different from the mode of being of the thing. It is not that the difference between mode of knowing and being implies that we do not know, but rather this difference is the very condition for knowledge to exist at all. Ayn Rand rightly said of this matter:

Even apart from the fact that Kant’s theory of the “categories” as the source of man’s concepts was a preposterous invention, his argument amounted to a negation, not only of man’s consciousness, but of any consciousness, of consciousness as such. His argument, in essence, ran as follows: man is limited to a consciousness of a specific nature, which perceives by specific means and no others, therefore, his consciousness is not valid; man is blind, because he has eyes—deaf, because he has ears—deluded, because he has a mind—and the things he perceives do not exist, because he perceives them.

Again, the Kantian may insist that perhaps we know the things. But again, we are just admitting we know the things as they appear to us, not as they are in themselves. So even if we know all things, we do not know their mode of being. The response is that we can know both the things and their mode of being, but we know both according to our mode of knowing, not according to their mode of being. This is similar to knowing someone else’s mode of knowing; when you do this, you do not therefore know with their mode of knowing, but with your own. Likewise, when you know the mode of the being of things, you know not with their mode of being, but with your own mode of knowing.

How does this answer our original question? Okay, you might say, there is no proof that there is anything that we cannot know in principle. But in practice it seems clear that our knowledge is entirely superficial, and thus hardly seems to be knowledge at all.

There is a large difference, however, between the assertion, “Most of our actual knowledge is rather superficial,” and the skeptical assertion, “Our knowledge is superficial in principle, and it is therefore impossible to know things as they truly are.” The first assertion is largely correct, and the second is quite wrong. It is true that the understanding of things that we attain “automatically,” as it were, from common experience, is a superficial knowledge, and thus ordinary language about ordinary things expresses such a superficial knowledge. It does not follow that a deep knowledge of things is impossible. However, if someone does not actually have such a deep knowledge, they may also misunderstand what it would even be like to have such a knowledge; and thus for example they might suppose that it would be necessary to have a knowledge of “things in themselves” in the Kantian sense, which of course is impossible, since it would eliminate the distinction between the mode of knowing and the mode of being.

In fact, not only is it not a contradiction to assert that we can know things as they are, but it would be a contradiction to assert, “There is something which we cannot know in any way, even in principle.” For “there is something” purports to refer to the thing and assert its existence, and such reference and assertion, if true, would be a kind of knowledge. Ludwig Wittgenstein makes the similar point, “We cannot think what we cannot think; so what we cannot think we cannot say either.”

It is not, however, a contradiction to say that there are some things that we cannot know in some ways. And this is surely true.