to prove the fame thing true in all particular circumftances whatfoever*; as if a traitor fhould argue from the fixth commandment, Thoufhalt not kill a mán, to prove that he himself ought not to be hanged; or if a madman fhould tell me I ought not to withhold his fword from him, because no man ought to withhold the property of another. a

Thefe two fpecies of fophifms are easily folved by fhewing the difference betwixt things in their abfolute, nature, and the fame things furrounded with peculiar circumstances, and confidered in regard to fpecial times,. places, perfons and occafions; or by fhewing the difference between a moral and metaphyfical univerfality, and that the propofition will hold good in one case, but not in the other.

VII. The fophifms of compofition and division come next to be considered.

The fophifm of compofition is when we infer any thing concerning ideas in a compounded fenfe, which is only true in a divided fenfe And when it is faid in the gofpel that Chrift made the blind to fee, and the deaf to bear, and the lame to walk, we ought not to infer hence, that Chrift performed contradictions; but thofe who were blind before were made to fee, and those who were deaf before were made to hear, &c. So when the fcripture affures us the worst of finners may be faved, it fignifies only, that they who have been the worst of finners may repent and be faved, not that they fhall be faved in their fins. Or if any one fhould argue thus, two and three are even and odd; five are two and three; therefore five are even and odd. Here that is very falfely inferred concerning two or three in union, which is only two of them divided..

The fophifm of divifion is when we infer the fame thing concerning ideas in a divided fenfe, which is only true in a compounded fenfe ; as, if we should pretend to prove, that every foldier in the Grecian army put an hundred thousand Perfians to flight, because the Grecian foldiers did fo. Or if a man should argue thus; five

*This is arguing from a moral univerfality, which admits of fome exceptions, in the fame manner as may be argued from metaphysical or a natural univerfality, which admits of no exception.

is one number; two and three are five; therefore two and three are one number.

This fort of fophifms is committed when the word All is taken in a collective and a diftributive fenfe, without a due diftinction; as, if any one thould reafon thus; all the mufical inftruments of the Jewith temple made a noble concert; the harp is a mufical inftrument of the Jewish temple, therefore the harp made a noble concert. Here the word All in the major is collective, whereas fuch a conclufion requires that the word All fhould be diftributive.

It is the fame fallacy when the univerfal word All or No refers to fpecies in one propofition, and to individuals in another; as, all animals were in Noah's ark; therefore no animals perished in the flood: whereas in the premise all animals fignifies every kind of animals, which does not exclude or deny the drowning of a thousand individuals.

VIII. The last fort of fophifms arifes from our abuse of the ambiguity of words, which is the largest and most extenfive kind of fallacy; and indeed feveral of the former fallacies might be reduced to this head.

When the words or phrafes are plainly equivocal, they are called Sophifms of Equivocation; as, if we fhould argue thus, he that fends forth a book into the light, defires it to be read; he that throws a book into the fire, fends it into the light: therefore he that throws a book into the fire defires it to be read.

This fophifm, as well as the foregoing, and all of the like nature, are folved by fhewing the different fenses of the words, terms or phrafes. Here light in the major propofition fignifies the public view of the world; in the minor it fignifies the brightness of flame and fire, and therefore the fyllogifm has four terms, or rather it has no middle term, and proves nothing.

But where fuch grofs equivocations and ambiguities appear in argument, there is little danger of impofing. upon ourselves or others. The greateft danger, and which we are perpetually exposed to in reafoning, is, where the two fenfes or fignifications of one term are near a-kin, and not plainly distinguished, and yet they are really fufficiently different in their fenfe to lead us

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into great mistakes, if we are not watchful. deed the greatest part of controverses in the fa credior civil life arife from the different fenfes that are put upon words, and the different ideas which are included in them; as hath been fhewn at large in the first part of Logic, Chap. IV. which treats of words and terms.i

There is, after all thefe, another fort of fophifm which is wont to be called an imperfect Enumeration, or a falfe Induction, when from a few experiments or obfervations, men infer general theorems and univerfal propofitions. But this is fufficiently noticed in the foregoing chapter, where we treated of that fort of fyllogifm which is called Induction..

4

SECT. II.

Two general Tests of true Syllogifms, and Methods of felving all Syllogifms.

B

ESIDES the fpecial defcription of true fyllogifms and fophifms already given, and the rules by which the one are framed, and the other refuted, there are these two general methods of reducing all fyllogifms. whatfoever to a teft of their truth or falfehood.

I. The firft is, that the premises must (at least im-plicitly) contain the conclusion; or thus, one of the premifes must contain the conclufion, and the other. muft fhew, that the conclufion is contained in it. The reafon of this rule is this; when any propofition is of-fered to be proved, it is neceffary to find another propofition which confirms it, which may be called the containing Propofitions; but because the second must not contain the first in an express manner, and in the fame word*, therefore it is neceffary that a third or oftensive

*It is confeffed, that the conditional and disjunctive major propofitions do exprefly contain all that is in the conclufion; but then it is not in a certain and conclusive manner, but only in a dubious form- of

propofition be found out, to fhew that the second propofition contains the first, which was to be proved. Let us make an experiment of this fyllogifm. Whosoever is a fave to his natural inclinations is miferable; the wicked man is a flave to his natural inclinations: therefore the wicked man is miferable. Here it is evident that the major propofition contains the conclufion for under the general character of a flave to natural inclinations, a wicked man is contained or included; and the minor propofition declares it; whence the conclufion is evidently deduced, that the wicked man is miferable.

In many affirmative fyllogifms we may fuppofe either the major or the minor to contain the conclufion, and the other to fhew it; for there is no great difference. But in negative fyllogifms it is the negative propofition that contains the conclufion, and the affirmative propofition fhews it; as, every wife man mafters his paflions; no angry man masters his paffion: therefore no angry man is wife. Here it is more natural to fuppofe the minor to be the containing propofition; it is the minor implicitly denies wisdom concerning an angry man, because mastering the pallions is included in wifdom, and the major fhews it.

Note, this rule may be applied to complex and conjunctive, as well as fimple fyllogifms, and is adapted to fhew the truth or falfehood of any of them.

II. The fecond is this, as the terms in every fyllogifm are usually repeated twice, fo they must be taken precifely in the fame fenfe in both places: for the greateft part of mistakes, that rife in forming fyllogifms, is derived from fome little difference in the fenfe of one of the terms in the two parts of the fyllogifms wherein it is ufed. Let us confider the following fophifm.

1. It is a fin to kill a man; a murderer is a man; therefore it is a fin to kill a murderer. Here the word kill in the first propofition fignifies to kill unjustly, or without a law, in the conclufion it is taken abfolutely for putting a man to death in general, and therefore the inference is not good.

fpeech, and mingled with other terms, and therefore it is not the fame exprels proposition.

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2. What I am you are not; but I am a man; therefore you are not a man. This is a relative fyllogifm: but if it be reduced to a regular categorical form, it will appear there is ambiguity in the terms, thus: what I am is a man; you are not what I am; therefore you Here what I am in the major propofition, is taken efpecially for my nature; but in the minor propofition the fame words are taken individually for my perfon; therefore the inference must be falfe, for the fyllogifms does not take the term what I am both times in the fame sense.

are not a man.

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3. He that fays you are an animal, fays true; but he that fays you are a goofe, you are an animal; therefore he that fays you are a goofe, fays true. In the major propofition the word animal is the predicate of an incidental proposition; which incidental proposition being affirmative, renders the predicate of it particular, according the Chap. II. Sect. 2. Axiom 3. and confequently the word animal there signifies only human animality. In the minor proposition, the word animal, for the fame reafon, signifies the animality of a goofe; whereby it becomes an ambiguous term, and unfit to build the conclusion upon. animal, in the minor, is tak then the minor is evidently falfe.

if you fay the word for human animality,

It is from this laft general teft of fyllogifms that we derive the cuftom of the refpondent in answering the arguments of the opponent, which is to diftinguish upon the major or minor proposition, and declare which term is ufed in two fenfes, and in what fenfe the proposition may be true, and in what fenfe it is falfe.

CHAP IV.

Some general Rules to direct our Reasoning.

OST of the general and special directions given to form our judgments aright in the preceding part of Logic might be rehearsed here; for the judgments