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to prove the fame thing true in all particular circum: Itances whatsoever*; as if a traitor should argue from the sixth commandment Thou shalt not kill a man, to prove that he'himself ought not to be hanged; or if a madman fhould tell me I ought not to withhold his sword from him, because no man ought to withhold the property of another. od 21 : These two species of sophisms are easily folved by fhewing the difference betwixt things in their absolute nature, and the fame things surrounded with peculiar circumítances, and considered in regard to fpecial tinies, places, persons and occasions; or by thewing the difference between a moral and metaphysical universality, and that the propofition will hold good in one case, but not in the other. ; - VII. The sophisms of composition and division come next to be considered. • The sophism of composition is when we infer any thing concerning ideas in a compounded sense, which is only true in a divided fense And when it is said in the gospel that Christ made the blind to see, and the deaf to hear, and the lame to walk, we ought not to infer hence, that Christ performed contradictions; but those 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 linners may be saved, it signifies only, that they who have been the worst of finners may repent and be saved, not that they fall be saved in their sins. Or if any one should argue thus, two and three are even ånd odd ; five are two and three ; therefore five are even and odd. Here that is very falsely inferred concerning two or three in union, which is only two of them divided i · The sophism of division is when we infer the fame thing concerning ideas in a divided fenfe, which is only true in a compounded sense ; as, if we should pretend to prove; that every soldier in the Grecian army put an hundred thousand Persianó to flight, because the Grecian foldiers did fo. Or if a man thould argue thus ; five
* This is arguing from a moral univerfality, which admits of some exceptions, in the same manner as may be argued from metaphysical or a natural universality, which admits of no exception,
is one number; two and three are five; therefore two and three are one number. a nie
This sort of sophisms is committed when the word Allis taken in a collective and a distributive sense, with. cuta due diftinction; as, if any one should reason thus; all the musical instruments of the Jewish temple made a noble concert; the harp is a musical insiruinent of the Jewish temple, therefore the harp, made a noble concert. Here the word All in the major is collective, whereas such a conclusion requires that the word All should be distributive.
It is the same fallacy when the universal word All or No refers to species 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 lait fort of sophisms arises from our abuse of the ambiguity of words, which is the largeft and most extenfive kind of fallacy; and indeed several of the former fallacies might be reduced to this head.
When the words or phrases are plainly equivocale, they are called Sophisms of Equivocation; as, if we fhould argue thus, he that sends forth a book into the light, delires it to be read; he that throws a book into the fire, sends it into the light : therefore he that throws a book into the fire defires it to be read.
This sophism, as well as the foregoing, and all of the like nature, are solved by shewing the different senses of. the words, terms or phrases. Here light in the major proposition signifies the public view of the world; in the minor it signifies the brightness of flame and fire, and therefore the syllogism has four terms, or rather it has no middle term, and proves nothing.
But where such gross equivocations and ambiguities appear in argument, there is little danger of impofing upon ourselves or others. The greatest danger, and which we are perpetually exposed to in reasoning, is, where the two fenses or significations of one term are near a-kin, and not plainly diftinguished, and yet they are really sufficiently different in their lense to lead us
into great mistakes, rib. we are not watchful. noAnd indeed the greatest part of coutroverkies in the sacred or eivil life arile from the different senses that are put upon words, and the different ideas which are included in them; as hath been thewn at large in the first part of Logic, Chap. IV. which treats of words and terms. It . There is, after all these, another fort of, fophism which is wont to be called an imperfect Enumeration; or: a false Induction, when from a few experiments or observations, men infer general theorems-and universal propositions. But this is sufficiently noticed in the toregoing chapter, where we treated of that sort of Syllogilm which is called Induction. . .
Two general Tests of true. Syllogisms, and Methods of solving
'all Syllogisms. D ESIDES the special description of true syllogisms
D and sophisms 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. whatsoever to a test of their truth or falsehood.
I. The first is, that the premises must (at least inn plicitly) contain the conclufion; or thus, one of the premises must contain the conclusion, and the other must Thew, that the conclusion is contained in it. The reason of this rule is this; when any proposition is of fered to be proyed, it is neceffàry to find another propo, Gition which confirms it, which may be called the containing Propositions ; but because the second must not contain the first in an express manner, and in the same word*, therefore it is necessary that a third or oitenfive
* It is confessed, that the conditional and disjunctive major propofitions do expreffy contain all that is in the conclusion ; but then it is not in a certain and conclusive manner, but only in a dubious forms of
propofition be found out, to fhew that the second proposition contains the first, which was to be proved. Let us make an experiment of this fyllogism. Whosoever is a flave to his natural inclinatiuns is miserable ; the wicked man is a flave to his natural inelinations : therefore the wicked man is miferable. Here it is evident that the major proposition contains the conclusion: for under the general character of a flave to natural inclinations, a wicked man is contained or included ; and the mnior proposition declares it ; whence the conclusion is evidently deduced, that the wicked man is miserable.
In many affirmative syllogisms we may suppose either the major or the ininor to contain the conclusion, and the other to shew it ; for there is no great difference. But in negative syllogisms it is the negative propofition that contains the conclusion, and the affirmative propofition shews it; as, every wise man masters his passions; no angry man masters his passion : therefore no angry man is wise. Here it is more natural to suppose 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 wisdom, and the major shews it.
Note, this rule may be applied to complex and conjunctive, as well as simple syllogisms, and is adapted to Thew the truth or falsehood of any of them.
II. The second is this , as the terms in every syllogism are usually repeated twice, so they must be taken precisely in the same sense in both places : for the greata eft part of mistakes, that rise in forming syllogisms, is derived from some little difference in the sense of one of the terms in the two parts of the syllogisms wherein it is used. Let us consider the following fophisin.
1. It is a sin 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 proposition signifies to kill unjustly, or without a law; in the conclusion it is taken abiolutely for putting a man to death in general, and therefore the inference is not good.
speech, and mingled with otlıer terms, and therefore it is not the same exprels proposition. w i
III. - 2. What I am you are not ; but I am a man; therefore you are not a man. This is a relative syllogism : but if it be reduced to a regular categorical forin, it will appear there is ambiguity in the terms, thus : what I am is a man ; you are not what I am ; therefore you are not a man. Here what I am in the major propofition, is taken especially for my nature ; but in the minor proposition the same words are taken individually for my person ;, therefore the inference must be falfe, for the syllogisms does not take the term what I am both times in the same sense. . 3. He that says you are an animal, says true ; but he that says you are a goose, you are an animal; therefore he that says you are a goose, says true, In the major proposition 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 centequently the word animal there signifies only human aniniality. In the minor proposition, the word animal, for the same reason, signifies the animality of a goose; whereby it becomes an ambiguous term, and unfit to build the conclusion upon. Or if you say the word animal, in the minor, is taken for human animality, then the minor is evidently false. ;. i i
It is from this last general test of syllogisms that we derive the custom of the respondent in aniwering the arguments of the opponent, which is to distinguish upoa the major or minor proposition, and declare which term is used in two senses, and in what sense the proposition may be true, and in what sense it is falle. it
Somne general Rules to direct our Rexifening." POST of the general and special directions given V to form our judgments aright in the preceding partot Logic might be rehearsed here; for the judgments