What connexion is there between factual statements concerning God or man and moral judgments? That is the question which occasions this paper. Not long ago moral philosophers were wont to say that there is a logical gap between the two sorts of utterance to which I have just referred: that nothing follows in terms of moral value from a statement of fact, no ‘ought’ from any ‘is’. They recognised only one restriction on what may be said in terms of ‘ought’ by what has been said in terms of ‘is’, namely that ‘ought’ implies ‘can’. It is manifest nonsense to say that anyone ought to do what he cannot do. But, this apart, they thought it possible without contradiction or anomaly to hold any conceivable factual belief and at the same time subscribe to any conceivable moral judgment. They would have held that it makes perfectly good sense to say, for example, ‘This is God’s will but it ought not to be done’ or ‘Men are not pigs but a good man will live like a pig’. Bizarre such judgments may be, they would have said, but nonsensical they are not. They conceived it to be their main business, as moral philosophers, to erect warning notices along the edge of the is-ought gap so that contemporary moralists would not fall headlong into it as so many of their predecessors, in less enlightened ages, had done.