Kant is a notoriously complex thinker, but he glossed his greatest contribution to philosophy in just two, crystal-clear sentences: ‘Hitherto it has been assumed that all our knowledge must conform to objects . . . We must therefore make trial whether we may not have more success in the tasks of metaphysics, if we suppose that objects must conform to our knowledge.’

The consequences of this ‘Copernican revolution in metaphysics’ are still being felt today. At one extreme, there are those who take the lesson of Kant to be that objectivity is a complete impossibility, and that all supposed knowledge is merely created, and more often than not an expression of power. Others take the lesson in a more sober way and claim that all Kant requires of us is to give up on a hopeless quest to know ‘things in themselves’ independent of experience. But that doesn’t require total scepticism about truth and objectivity. It simply requires a more subtle understanding of what these notions mean, and an acceptance that we cannot achieve a ‘god’s eye view’ of reality.

Those who claim to be carrying the flame of the Enlightenment often ignore the insight of one of that movement’s greatest thinkers. We have become reluctant to admit that knowledge is essentially framed by the human mind for fear of sliding down a slippery slope that ends with the irrationality of total relativism. But unless we take into account Kant’s Copernican revolution, our paeans to reason and truth will amount to no more than naïve praise of a long-dead myth.