IN this chapter I hope to pay back an important question which I have had to beg up till now-the question whether philosophical disputes can be settled by appeal to logical criteria. The operative word here is ‘disputes*. The answers to philosophical questions can sometimes be tested by seeing whether they follow deductively from agreed premises. But, when and if this is so, the answers are (I shall contend) indubitable; there is no reason and no occasion for dispute about them. Conversely, when there is a dispute, this is prima facie evidence that the question cannot in fact be settled in this way. Indeed, as is beginning to be acknowledged, the intractability of philosophical disagreement suggests that none of the criteria explicitly adopted in current discussion is really up to the job. I shall try to show that (and why) this is the case.