DEFINITE

In Chemistry. See Affinity. PROPOSPTION, in Logic, is defined " a sentence indicative;" i. e. a sentence which affirms or denies. Thus, sentences in the form of command or question are excluded from the character of propositions. Logical propositions are said to be divided, first, according to substance, into categorical and hypothetical; secondly, according to quality, into affirmative and negative; thirdly, according to quantity, into universal and particular. 1. A categorical proposition is where the sentence affirms or denies absolutely, as "man is mortal." A hypothetical proposition is defined to be two or more categoric als united by a conjunction, as " if Caius is man, he is mortal." There are several sorts of hypothetical propositions; conditional, disjunctive, causal, . 2. An affirmative proposition is one whose copula (or conjunction) is affirmative, as " man is mortal; " a negative proposition has a negative copula, as " man is not immortal." 3. An universal proposition is when the predicate is said of the whole of the subject, as " all men are mortal," " Caius is mortal; " a particular, when it is said of part of the subject only, as "some men are rich." To these two species may be added the indefinite proposition, when the subject has no sign of universality or particularity, or is a singular noun, which is either universal or particular according to the matter. The matter of a proposition is said to be either nece ary, impo ible, or contingent; and if the matter of an indefinite proposition be either of the former, it is equivalent to an universal; if the last, to a particular: e.g. "birds fly," i.e. all birds — universal. " No birds are quadrupeds; " here the matter is impo ible, and the proposition universal. " Birds sing," i. c. some birds -_ particular. The fourfold division of propositions according to quality and quantity is denoted by arbitrary signs; e.g. A stonds for an universal affirmative, in the logic used at 992 [s. 1005]