In his Hayek on Liberty John Gray comes to the conclusion that ‘the result of the moral emptiness of Hayek’s theory of cultural evolution for political philosophy is that his system lacks definite normative standards for the critical assessment of political practice’. He then raises the question, ‘How then might this effect be remedied?’ and answers, ‘Not, to be sure, by recourse to any doctrine of natural rights. . . . Theories of natural law, are . . . indefensible in modern terms. They presuppose a teleology of nature’ (Gray 1986: 142). It will be argued here that Gray’s opinion is mistaken. He says that ‘doctrines of natural law are at home only in the contexts in which they emerged historically – in Aristotle’s mystical biology and in Locke’s theism’ (ibid.: 143). Gray thus ignores Kant’s theory of morality and (natural) law. Kant’s theory of natural law does not presuppose a teleology of nature, even though he assumed a belief in God as a regulative idea of moral and historical philosophy. That Gray ignored Kant, is surprising in view of his characterization of Hayek’s thinking as ‘informed by a distinctively Kantian approach’ (ibid.: 4). Moreover, Hayek himself has recognized the closeness between Kant’s and his own philosophy of law (Hayek 1982, vol. 2; 166).1 Contrary to Gray again, it will also be argued that Hayek’s view of natural law theory should be taken into consideration by those liberals who think that Hayek’s views on law, state and politics are more or less what they stand for, but who are not convinced that Hayek’s theoretical framework is consistent and strong enough.