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ought to be conjoined. 5. is an ambiguity in profody, accent, or pronunciation. 6. An ambiguity arifing from fome figure of fpeech.

When a sophism of any of these kinds is tranflated into another language, or even rendered into unambiguous expreffions in the fame language, the fallacy is evident, and the fyllogifm appears

to have four terms.

The feven fallacies which are faid not to be in the diction, but in the thing, have their proper names in Greek and in Latin, by which they are distinguished. Without minding their names, we fhall give a brief account of their nature.

1. The first is, Taking an accidental conjunction of things for a natural or neceffary connection: as, when from an accident we infer a property; when from an example we infer a rule; when from a fingle act we infer a habit.

2. Taking that abfolutely which ought to be taken comparatively, or with a certain limitation. The conftruction of language often leads into this fallacy: for in all languages it is common to ufe abfolute terms, to fignify things which carry in them fome fecret comparison; or to use unlimited terms, to fignify what from its nature must be limited,

3. Taking that for the cause of a thing which was only an occafion, or concomitant.

4. Begging the question. This is done, when the thing to be proved, or fome thing equivalent, is affumed in the premises.

5. Mistaking the question. When the conclufion of the fyllogifin is not the thing that ought to be proved, but something else that is mistaken for it.

6. When that which is not a confequence is mistaken for a confequence; as if, because all Africans are black, it were taken for granted that all blacks are Africans.

7. The laft fallacy lies in propofitions that are complex, and


F f


imply two affimations, whereof one may be true, and the other false; fo that whether you grant the propofition, or deny it, you are intangled as when it is affirmed, that fuch a man has left off playing the fool. If it be granted, it implies, that he did play the fool formerly. If it be denied, it implies, or feems to imply, that he plays the fool ftill.

In this enumeration, we ought, in justice to Aristotle, to expect only the fallacies incident to categorical fyllogifms. And I do not find, that the logicians have made any additions to it when taken in this view; altho' they have given fome other fallacies that are incident to fyllogifms of the hypothetical kind, particularly the fallacy of an incomplete enumeration in disjunctive fyllogifms and dilemmas.

The different fpecies of fophifms above mentioned are not fo precisely defined by Aristotle, or by fubfequent logicians, but that they allow of great latitude in the application; and it is often dubious under what particular fpecies a fophiftical fyllogifm ought to be claffed. We even find the fame example brought under one fpecies by one author, and under another species by anther. Nay, what is more ftrange, Ariftotle himself employs à long chapter in proving by a particular induction, that all the feven may be brought under that which we have called miftaking the queftion, and which is commonly called ignoratio elenchi. And indeed the proof of this is eafy, without that laborious detail which Ariftotle ufes for the purpose: for if you lop off from the conclu fion of a fophiftical fyllogifm all that is not fupported by the premifes, the conclufion, in that cafe, will always be found different from that which ought to have been proved; and fo it falls under the ignoratio elenchi.

It was probably Ariftotle's aim, to reduce all the poffible variety of fophifms, as he had attempted to do of juft fyllogifms, to certain definite fpecies: but he seems to be fenfible that he had


fallen fhort in this last attempt. When a genus is properly divided into its fpecies, the fpecies fhould not only, when taken together, exhaust the whole genus; but every fpecies fhould have its own precinct fo accurately defined, that one fhall not encroach upon another. And when an individual can be faid to belong to two or three different fpecies, the divifion is imperfect; yet this is the cafe of Ariftotle's divifion of the fophifms, by his own aċknowledgement. It ought not therefore to be taken for a divifion ftrictly logical. It may rather be compared to the several species or forms of action invented in law for the redress of wrongs. For every wrong there is a remedy in law by one action or another : but sometimes a man may take his choice among several different actions. So every fophiftical fyllogifm may, by a little art, be brought under one or other of the fpecies mentioned by Aristotle, and very often you may take your choice of two or three.

Befides the enumeration of the various kinds of fophifms, there are many other things in this treatise concerning the art of managing a fyllogistical dispute with an antagonist. And indeed, if the paffion for this kind of litigation, which reigned for fo many ages, fhould ever again lift up its head, we may predict, that the Organon of Ariftotle will then become a fashionable study: for it contains fuch admirable materials and documents for this art, that it may be faid to have brought it to a science.

The conclufion of this treatise ought not to be overlooked: it manifeftly relates, not to the present treatise only, but alfo to the whole analytics and topics of the author. I fhall therefore give the fubftance of it.

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"Of those who may be called inventers, fome have made important additions to things long before begun, and carried on through a course of ages; others have given a finall beginning to things which, in fucceeding times, will be brought to greater perfection. The beginning of a thing, though finall, is the "chief


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"chief part of it, and requires the greatest degree of invention; "for it is easy to make additions to inventions once begun. Now "with regard to the dialectical art, there was not fomething done, "and fomething remaining to be done. There was abfolutely nothing done for those who profeffed the art of disputation, "had only a set of orations compofed, and of arguments, and of captious queftions, which might fuit many occafions. These "their scholars foon learned, and fitted to the occafion. This 66 was not to teach you the art, but to furnish you with the mate"rials produced by the art: as if a man profeffing to teach you "the art of making fhoes, fhould bring you a parcel of fhoes of "various fizes and fhapes, from which you may provide those "who want. This may have its ufe; but it is not to teach the art of making fhoes. And indeed, with regard to rhetorical "declamation, there are many precepts handed down from an"cient times; but with regard to the conftruction of fyllogifms,

not one.

We have therefore employed much time and labour upon "this fubject; and if our system appears to you not to be in the "number of those things, which, being before carried a certain "length, were left to be perfected; we hope for your favourable acceptance of what is done, and your indulgence in what is left imperfect."

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Reflections on the Utility of Logic, and the Means of its Improvement.

SECT. I. Of the Utility of Logic.

MEN EN rarely leave one extreme without running into the contrary. It is no wonder, therefore, that the exceffive admiration of Aristotle, which continued for fo many ages, should end in an undue contempt; and that the high esteem of logic as the grand engine of science, fhould at last make way for too unfavourable an opinion, which feems now prevalent, of its being unworthy of a place in a liberal education. Those who think according to the fashion, as the greatest part of men do, will be as prone to go into this extreme, as their grandfathers were to go into the contrary.

Laying afide prejudice, whether fashionable or unfashionable, let us confider whether logic is, or may be made, fubfervient to any good purpose. Its profeffed end is, to teach men to think, to judge, and to reason, with precifion and accuracy. No man will fay that this is a matter of no importance; the only thing, therefore, that admits of doubt, is, whether it can be taught.

To refolve this doubt, it may be obferved, that our rational faculty is the gift of God, given to men in very different measure. Some have a larger portion, fome a lefs; and where there is a remarkable defect of the natural power, it cannot be fupplied by


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