The duty of mankind, as God's creatures, to obey their divine creator was the central axiom of John Locke's thought. The entire framework of his thinking was ‘theocentric’ and the key commitment of his intellectual life as a whole was the epistemological vindication of this framework. It is still a controversial question precisely what the religious opinions of David Hume and Adam Smith in fact were. But it would certainly be a profoundly implausible claim to make in relation to either that the framework of their thinking was in any sense ‘theocentric’. Whether or not either was in any theoretical sense an atheist, it is fair to describe each as being, as David Gauthier terms Hobbes, ‘a practical atheist’: someone for whom, if God does exist, at least his existence makes no practical difference to the sane conduct of human life. It is scarcely surprising that the acquaintance of a practical atheist like Hume should have troubled the neurotic and credulous James Boswell, whose conduct even when Hume was virtually on his deathbed fully merited the latter's lapidary rebuke on an earlier occasion that ‘it required great goodness of disposition to withstand the baleful effects of Christianity’. But it is historically more striking and more illuminating to notice that their (on the whole very discreet) practical atheism would certainly in Locke's eyes have put Hume and perhaps even a wholly honest Smith, at least in later life, beyond the pale of toleration: ‘Promises, covenants, and oaths, which are the bond of human society, can have no hold upon or sanctity for an atheist; for the taking away of God, even only in thought, dissolves all.’