Distinguish, in this Analysis, to avoid subsequent confusion, between the Subject and the Subject Term, the Predicate and the Predicate Term. The Subject is the Subject Term quantified: in A and E,[1] "All S"; in I and O, "Some S". The Predicate is the Predicate Term with the Copula, positive or negative: in A and I, "is P"; in E and O, "is not P". It is important also, in the interest of exactness, to note that S and P, with one exception, represent general names. They are symbols for classes. P is so always: S also except when the Subject is an individual object. In the machinery of the Syllogism, predications about a Singular term are treated as Universal Affirmatives. "Socrates is a wise man" is of the form All S is P. S and P being general names, the signification of the symbol "is" is not the same as the "is" of common speech, whether the substantive verb or the verb of incomplete predication. In the syllogistic form, "is" means _is contained in_, "is not," _is not contained in_. The relations between the terms in the four forms are represented by simple diagrams known as Euler's circles. [Illustration: 1 concentric circles of P and S - S in centre A 2 S and P in the same circle A 3 S and P each in a circle, overlapping circle. I & O 4 S in one circle and P in another circle. E 5 concentric circles of S and P - P in centre I? ] Diagram 5 is a purely artificial form, having no representative in common speech. In the affirmations of common speech, P is always a term of greater extent than S. No. 2 represents the special case where S and P are coextensive, as in All equiangular triangles are equilateral. S and P being general names, they are said to be DISTRIBUTED when the proposition applies to them in their whole extent, that is, when the assertion covers every individual in the class. In E, the Universal Negative, both terms are distributed: "No S is P" wholly excludes the two classes one from the other, imports that not one individual of either is in the other. In A, S is distributed, but not P. S is wholly in P, but nothing is said about the extent of P beyond S. In O, S is undistributed, P is distributed. A part of S is declared to be wholly excluded from P. In I, neither S nor P is distributed. It will be seen that the Predicate term of a Negative proposition is always distributed, of an Affirmative, always undistributed. A little indistinctness in the signification of P crept into mediaeval text-books, and has tended to confuse modern disputation about the import of Predication. Unless P is a class name, the ordinary doctrine of distribution is nonsense; and Euler's diagrams are meaningless. Yet many writers who adopt both follow mediaeval usage in treating P as the equivalent of an adjective, and consequently "is" as identical with the verb of incomplete predication in common speech.