In spite of its horrifying title Kant’s Groundwork of the Metaphysic of Morals is one of the small books which are truly great: it has exercised on human thought an influence almost ludicrously disproportionate to its size. In moral philosophy it ranks with the Republic of Plato and the Ethics of Aristotle; and perhaps–partly no doubt through the spread of Christian ideals and through the long experience of the human race during the last two thousand years, it shows in some respects a deeper insight even than these..