5. THE DICTUM OF ARISTOTLE.
Aristotle gives an axiom on which all syllogistic inference is based. Indeed from this fundamental principle the significant rules of the syllogism could be derived. The dictum is stated in this wise: “Whatever is predicated, whether affirmatively or negatively, of a term distributed may be predicated in the manner of everything contained under it.” The following statements represent various ways of explaining this dictum:
(1) Whatever is said of a term used in its fullest sense may likewise be said of that term when used only in a partial sense.
(2) What is true of the whole is true of the part.
(3) “What pertains to the higher class pertains also to the lower.” Since this dictum is the basic principleunderlying the important rules of the syllogism, it is unnecessary to dwell longer upon it; because an explanation of the rules is, virtually, an explanation of the dictum.