When I look up at Thy heavens, the work of Thy fingers, the moon and the stars set in their place by Thee, what is man, that Thou shouldst remember him, mortal man that Thou shouldst care for him? Yet Thou hast made him little less than a god, crowning him with glory and honour. (Psalm VIII)
It is often said that the three greatest philosophers of all time were Plato, Aristotle, and Kant. The third of these now makes his mark on our enquiry.
Immanuel Kant (1724-1804) was born in Königsberg in Prussia and lived there all his life. Much of his philosophy was devoted to taking rival systems of thought and rooting out the inveterate assumptions common to them. On the one hand this enabled him to show that some of the fundamental points of controversy between them were ill-conceived. On the other hand it enabled him to salvage and to reconcile some of their apparently irreconcilable insights. The latter was something that he sought to do above all in the case of the conflict between traditional Christian morality and Newton’s (by now) well-established mechanics. Christian morality seemed to make no sense without human freedom, but there was no room for human freedom, it seemed, in Newton’s world of inexorable mechanical laws. In attempting a reconciliation here, Kant developed a philosophical system of breathtaking depth and power. Indeed it enabled him at the same time and in much the same way to arbitrate between the rationalists and the empiricists. Since they have just been the focus of our attention, let us broach Kant’s system in those terms.
Kant wanted to accept, with the rationalists, that we had substantial a priori knowledge. Yet, in line with the empiricists, he did not see how we could know anything substantial about what was out there, independent of us, without letting it impinge on us through experience. He resolved the apparent conflict here by arguing that the a priori knowledge in question was not after all knowledge about what was out there, independent of us.