Aristotle does not define the object of Dialectic as exactly as I have done it here; for while he allows that its principal object is disputation, he declares at the same time that it is also the discovery of truth.[1] Again, he says, later on, that if, from the philosophical point of view, propositions are dealt with according to their truth, Dialectic regards them according to their plausibility, or the measure in which they will win the approval and assent of others.[2] He is aware that the objective truth of a proposition must be distinguished and separated from the way in which it is pressed home, and approbation won for it; but he fails to draw a sufficiently sharp distinction between these two aspects of the matter, so as to reserve Dialectic for the latter alone.[3] The rules which he often gives for Dialectic contain some of those which properly belong to Logic; and hence it appears to me that he has not provided a clear solution of the problem. [Footnote 1: _Topica_, bk. i., 2.] [Footnote 2: _Ib_., 12.] [Footnote 3: On the other hand, in his book _De Sophisticis Elenchis_, he takes too much trouble to separate _Dialectic_ from _Sophistic_ and _Eristic_, where the distinction is said to consist in this, that dialectical conclusions are true in their form and their contents, while sophistical and eristical conclusions are false. Eristic so far differs from Sophistic that, while the master of Eristic aims at mere victory, the Sophist looks to the reputation, and with it, the monetary rewards which he will gain. But whether a proposition is true in respect of its contents is far too uncertain a matter to form the foundation of the distinction in question; and it is a matter on which the disputant least of all can arrive at certainty; nor is it disclosed in any very sure form even by the result of the disputation. Therefore, when Aristotle speaks of _Dialectic_, we must include in it Sophistic, Eristic, and Peirastic, and define it as "the art of getting the best of it in a dispute," in which, unquestionably, the safest plan is to be in the right to begin with; but this in itself is not enough in the existing disposition of mankind, and, on the other hand, with the weakness of the human intellect, it is not altogether necessary. Other expedients are required, which, just because they are unnecessary to the attainment of objective truth, may also be used when a man is objectively in the wrong; and whether or not this is the case, is hardly ever a matter of complete certainty.