xtent 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.

It should be recognised that these syllogistic forms are purely
artificial, invented for a purpose, namely, the simplification of
syllogising. Aristotle indicated the precise usage on which his
syllogism is based (_Prior Analytics_, i. 1 and 4). His form[2] for
All S is P, is S is wholly in P; for No S is P, S is wholly not in P.
His copula is not "is," but "is in," and it is a pity that this usage
was not kept. "All S is in P" would have saved much confusion. But,
doubtless for the sake of simplicity, the besetting sin of tutorial
handbooks, All S is P crept in instead, illustrated by such examples
as "All men are mortal".

Thus the "is" of the syllogistic form became confused with the "is"
of common speech, and the syllogistic view of predication as
being equivalent to inclusion in, or exclusion from a class, was
misunderstood. The true Aristotelian doctrine is not that predication
consists in referring subjects to classes, but only that for certain
logical purposes it may be so regarded. The syllogistic forms are
artificial forms. They were not originally intended to represent the