"David Hume, sceptic, suspected atheist and Tory, was not a man with whom Burke was likely to claim affiliations; but Hume it is, nevertheless, who in the first half of the eighteenth century introduces clearly those principles which were to emerge more definitely later in the theories of Burke and the Romantic movement. Locke had substituted empiricism for rationalism in philosophy, but he still treated ethics and politics as deductive sciences of the same nature as mathematics. Hume carries the attack on rationalism into these fields and enounces a naturalism which anticipates in many respects the subsequent return to nature of the Romantics."