cases that names are supposed to denote" (p. 21). "In this way, therefore, the picture we get of distinctions in general is that they are really fluid, but artificially hard; that the apparent absence of a borderland between (actual) A and Non-A is a result of our incomplete powers of vision wherever it is not a result of deliberately shutting our eyes to some of the facts. Either the transition is too quick for our clumsy observation, or in some way the process is hidden from us at present, and is therefore liable to become manifest whenever our observing power, or our insight into past history or remote places, shall become sufficiently improved" (p. 73).
This vindication of "inexact" thinking reminds one of Aristotle's maxim, that the exactness of our treatment ought to be proportionate to the subject-matter of the inquiry; it is a modern version of that maxim, generalized (where Aristotle said some subjects are inexact, Mr. Sidgwick says all"), and founded on the doctrine of Evolution, which exhibits the "origin of species," and proves that the greatest and most obvious distinctions are the result of accumulation of the smallest and least perceptible variations. But instead of pursuing the inviting inquiry which he has thus opened up into the Logic of Evolution and discussing, for example, how far the Hegelian dialectic, with its categories that "pass over" into one another, overcomes the defects of the Aristotelian logic with its rigid, static distinctions, and is adequate to the interpretation of the subtle processes of nature, Mr. Sidgwick turns his attention to the practical bearings of the doctrine of the "rough distinction" upon the settlement of controversy. This turn of the discussion is disappointing to the more speculative reader, but is entirely in keeping with the object of the book, and no doubt more profitable for the audience he has especially in view.
All thought, particularly as expressed in language, is convicted of "unreal distinctions." "Every distinction is rough if we choose to be strict in demanding applicability; the charge must, therefore, be admitted and yet somehow disarmed, if we are to avoid the deadlock into which the continuity of Nature at first appears to lead" (pp. 143, 144). The charge is disarmed, and universal scepticism avoided, by considering the "relevancy" of the distinction to the "purpose" or "occasion." The validity of distinctions, it is maintained, is not absolute, but relative to the argument in which they are used; and, relatively to the argument, a distinction may be legitimately interpreted as "sharp," while, absolutely and "really," it is only "rough." "For the essence of scepticism is casuistry, or the inquiry after a description which shall be applicable to actual cases, instead of merely general and abstract We shall see that such an inquiry can never be satisfied, and that therein lies the strength of the sceptical attack; but we shall also
