The arte of logick Plainely taught in the English tongue, according to the best approued authors. Very necessary for all students in any profession, how to defend any argument against all subtill sophisters, and cauelling schismatikes, and how to confute their false syllogismes, and captious arguments. By M. Blundevile.

CHAP. X.

Of a compound or hypotheticall proposition.

WHat is a compound proposition?

It is that which consisteth of two or more sim∣ple propositions, coupled together with some coniunction.

How manifold is it?

Threefold, Conditionall, Copulatiue, and Disiunctiue.

When is it said to be conditionall?

When the coniunction If is set before any simple proposition, as thus: If it be a man, it is a sensible body.

When is it said to be copulatiue?

When two simple propositions are ioined together with a con∣iunction copulatiue, as, God is true, and man is a lier.

When is it said to be disiunctiue?

When two simple propositions are ioined together with a coniunction disiunctiue, as thus; Either it is day, or night.

Of how many parts doth a compound proposition consist?

Of two, that is, of the antecedent, and of the consequent?

Which call you the antecedent?

That which followeth next after the coniunction, as thus: If it be iustice, it is a vertue: here this speech, If it be iustice, is the an∣tecedent, and the rest of the speech, that is to say, it is a vertue, is the consequent: and so it should be, though the words were con∣trarily placed, as thus: It is a vertue, if it be iustice.

What things are to be considered in hypotheticall propositions?

These: First, whether they haue any quantitie, or qualitie: then, whether any opposition, equiualence, or conuersion doe belong to them, or not: thirdly, how to know the truth or fals∣hood of euery such proposition, be it conditionall, copulatiue, or disiunctiue. And first, as touching quantitie, they haue none at all: for quantitie is to be measured by signes vniuersall, or parti∣cular, which are only incident to the subiects of categoricall pro∣positions: but qualitie they haue, in that they affirme or denie some thing, by reason whereof there may be contradiction in

hypotheticall propositions, but it cannot bee properly said, that they be either contrarie, subcontrarie, or subalternat, for that they are without quantitie; for want whereof they nei∣ther doe aptly admit opposition, equiualence, or conuersion, but onely contradiction.

How is that Contradiction to be vnderstood?

By reason of affirmation, or negation; which, as in simple propositions is to be taken on the behalfe of the verbe copula∣tiue, and not of the subiect or predicate: so in compound propositions, it is to be taken on the behalfe of the coniuncti∣on, hauing a negatiue set before it; and yet not of euery con∣iunction, but onely of that coniunction conditionall, If: whereof I cannot aptly giue you any example in our natiue tongue, because it is contrarie to our naturall and vsuall speech, to put a negatiue before the coniunction, If; and therefore I leaue to speake thereof any further: and to say the truth, it ma∣keth but a strange kinde of speech in the Latine tongue, and I beleeue is seldome vsed in any disputation: as to say thus, Non si animal est, homo est: or, Non si lux est, dies est: both which are said to be negatiue speeches, according to the rule before giuen, because the negatiue is set before the coniuncti∣on si, and by vertue thereof (as the Schoolemen say) maketh the whole proposition to be negatiue.