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CHAP. XXVIII.
Of Syllogistick Conclusive Reasons, or Syllogisms.
COnclusive reasons, as to their from likewise, are of two kinds; Syllogistically conclusive, and not Syllogistically conclusive. a 1.1 Syllogistically-conclusive Reasons (or Syllogismes) are those which either cannot be more concluded, or whereof one or more of the sumptions are reduced to those which cannot be concluded again; as, if Dion walks, he is moved.
Syllogismes (by which the Stoicks understand only the tro∣picall, or hypotheticall,) are of three kinds, connex, disjunct, con∣junct.
b 1.2 A connex Syllogism is, when two are so connected in them∣selves, that one is the antecedent, the other the consequent, in such manner, as, if the antecedent be asserted, the consequent follow∣eth, and the consequent being taken away, the antecedent is like∣wise taken away, as, if it be day, it is not night, this antecedent is true, therefore it followeth, it is night. This kind of Syllogisme pertains to the first and second moods. In the first it is called from Position of the antecedent, to Position of the consequent; in the second, from negation of the antecedent, to negation of the consequent. The Lawes concerning the truth, or falshood of these Syllogismes are the same with those of connex axioms.
Of connex Syllogismes there are two kinds; connex in them∣selves, as, if it is light, it is ligh••, but it is light, therefore it is light; and connex by others; as, if it is day, it is light, but it is day, therefore it is light.
A conjunct Syllogisme, is,c 1.3 when we deny somthing conjunct, and to these adde another negation, and of these take the first, that what remains be taken away, as,d 1.4 it cannot be that a Lega∣cy is money, and money not a Legacy; but a Legacy is money, therefore money is a Legacy.
e 1.5 A disjunct Syllogism is that in which there cannot be more then one thing true, or, that in which if one be, the other is not, or, if one be not, the other is, as, It is either day or night, but it not night, therefore it is day; for one being asserted, the other is taken away, and so on the contrary.f 1.6 The evidence of this Syllogisme Chrysippus conceives to be so great, that even dogs have knowledge thereof. For coming to a place where there are three waies, if by the sent they find that the Beast hath not gone in two of them, they run directly to the third without senting, as if they argued thus, the Beast went either this way, or that way, or that way, but neither this way nor that way, therefore that way: The Laws of disjunct Syllogismes are the same as those of disjunct Axioms.