Biologist E. O. Wilson tries a different tack. Science, he says, is giving us new senses that are enabling us to go beyond our previous perceptual limitations. “With the aid of appropriate instruments we can now view the world with butterfly eyes.” With receivers and transformers and night-time photography we can experience the world in pretty much the same way as a bat. “Fish.” Wilson tells us, “communicate with one another by means of coded electrical bursts. Zoologists, using generators and detectors, can join the conversation.”

If by this point you have grasped Kant’s reasoning, you will see right away that Wilson has done nothing to undermine it. Yes, we can use night-time photography, but we are still viewing the images with our human eyes. Yes, we can use generators and detectors, but we are still using our five senses in order to read, hear, and interpret what those instruments say. In other words, our human apparatus of perception conditions theentire field of our experiences, and this has always been so and will continue to be so as long as we are human. Future scientific discoveries cannot alter this limitation because those discoveries too will have to be made and experienced through the constrained perceptual apparatus we possess. Kant’s conclusion was that the problem of reason is, in its fullest dimension, insoluble. There are permanent and inescapable limits to human reason, and it is foolish to go on pretending otherwise.

While this conclusion that our reason is confined within the borders of our experience, and that reality in itself in permanently screened off from us by our own sensory limitations, may seem to some to be a very outlandish idea, in fact it is at the very center of Western philosophy. In perhaps the most famous metaphor in Western thought, Plato likened human beings to people living in a cave, shut out from the light of the sun, seeing only shadows and mistaking them for reality. Plato regarded our perceptions as mere images of a deeper and higher reality, the so-called Platonic forms, that he located somewhere outside the realm of human experience. And Plato’s teacher, Socrates, regarded himself as the wisest man in Athens because he alone knew how little fie knew. For all his breathtaking originality, Kant is squarely in the mainstream of Western thought.

No one who understands the central doctrines of any of the world’s leading religions should have any difficulty understanding Kant, because his philosophical vision is congruent with the teachings of Hinduism, Buddhism, Islam, Judaism, and Christianity. It is a shared doctrine of these religions that the empirical world we humans inhabit is not the only world there is. Ours is a world of appearances only, a transient world that is dependent on a higher, timeless reality. That reality is of a completely different order from anything that we know, it constitutes the only permanent reality there is, and it sustains our world and presents it to our senses. Chris- tianity teaches that while reason can point to the existence of this higher domain, this is where reason stops: it cannot on its own investigate or comprehend that domain. But one day, it is promised, when our earthly journey is over, we will know the higher realm and see things as they really are.