Enthymeme. This term in our ordinary
logical treatises denotes, and for ages has denoted, a syllogism of
which one of the premisses is suppressed in utterance, and the
which is the main element in the formation of the word, has been
absurdly supposed to give it the meaning of something thought but not
uttered. Cogito ergo sum is an enthymeme, though its author Descartes did not
say it for argumentative ends. The suppressed premiss is quicquid
cogitat est. He is contented because he is happy. Here the conclusion
needs for its validity a premiss which is not expressed. All the
contented are happy.
This is quite different, however, from what Aristotle meant by the
enthymeme. In his use of the term it denoted a syllogism from probable
propositions or signs. The murderer must have been near at the time. The
prisoner was near at the time. Therefore he was the murderer.(1) It is
obvious that this is not absolutely conclusive, but a combination of
such signs will often be so cogent as to produce rational conviction.
The probable premiss is, as its name imports, no more than probable. The
sign may be probable or it may be necessary.(2)
(1) Archbishop Thomson.
(2) ARISTOTLE, Anal. Pr. II, 27.