_b._ The second treatise is on Interpretation (περὶ ἑρμηνείας); it is the doctrine of judgments and propositions. Propositions exist where affirmation and negation, falsehood and truth are enunciated;[115] they do not relate to pure thought when reason itself thinks; they are not universal but individual.
_c._ The Analytics come third, and there are two parts of them, the Prior and the Posterior; they deal most fully with proof (ἀπόδειξις) and the syllogisms of the understanding. “The syllogism is a reason (λόγος) in which if one thing is maintained, another than what was maintained follows of necessity.”[116] Aristotle’s logic has treated the general theory of conclusions in the main very accurately, but they do not by any means constitute the universal form of truth; in his metaphysics, physics, psychology, &c., Aristotle has not formed conclusions, but thought the Notion in and for itself.
_d._ The Topics (τοπικά) which treat of ‘places’ (τόποι) come fourth; in them the points of view from which anything can be considered are enumerated. Cicero and Giordano Bruno worked this out more fully. Aristotle gives a large number of general points of view which can be taken of an object, a proposition or a problem; each problem can be directly reduced to these different points of view, that must everywhere appear. Thus these ‘places’ are, so to speak, a system of many aspects under which an object can be regarded in investigating it; this constitutes a work which seems specially suitable and requisite for the training of orators and for ordinary conversation, because the knowledge of points of view at once places in our hands the possibility of arriving at the various aspects of a subject, and embracing its whole extent in accordance with these points of view (Vol. I. p. 358). This, according to Aristotle, is the function of Dialectic, which he calls an instrument for finding propositions and conclusions out of probabilities.[117] Such ‘places’ are either of a general kind, such as difference, similarity, opposition, relation, and comparison,[118] or special in nature, such as ‘places’ which prove that something is better or more to be desired, since in it we have the longer duration of time, that which the one wise man or several would choose, the genus as against the species, that which is desirable for itself; also because it is present with the more honourable, because it is end, what approximates to end, the more beautiful and praiseworthy, &c.[119] Aristotle (Topic VIII. 2) says that we must make use of the syllogism by preference, with the dialectician, but of induction with the multitude. In the same way Aristotle separates[120] the dialectic and demonstrative syllogisms from the rhetorical and every kind of persuasion, but he counts induction as belonging to what is rhetorical.