fiftency upon every question that can oc

eur.

*

Every question is either about the genus of the subject, or its specific difference, or fome thing proper to it, or fomething accidental.

To prove that this divifion is complete, Aristotle reasons thus: Whatever is attributed to a fubject, it must either be, that the fubject can be reciprocally attributed to it, or that it cannot. If the fubject and attribute can be reciprocated, the attribute either declares what the subject is, and then it is a definition; or it does not declare what the fubject is, and then it is a property. If the attribute cannot be reciprocated, it must be fomething contained in the definition, or not. If it be contained in the definition of the subject, it must be the genus of the subject, or its specific difference; for the definition confifts of these two. If it be not contained in the definition of the fubject, it must be an accident.

The furniture proper to fit a man for arguing dialectically may be reduced to these four heads: 1. Probable propofitions of all forts, which may on occafion be assumed

in an argument. which are nearly of the fame fignification. 3. Diftinctions of things which are not fo far afunder but that they may be taken for one and the fame. 4. Similitudes.

2. Diftinctions of words

The second and the five following books are taken up in enumerating the topics or heads of argument that may be used in questions about the genus, the definition, the properties, and the accidents of a thing; and occafionally he introduces the topics. for proving things to be the fame, or different; and the topics for proving one thing to be better or worfe than another.

In this enumeration of topics, Ariftotle has fhewn more the fertility of his genius, than the accuracy of method. The writers of logic feem to be of this opinion: for I know none of them that has followed him closely upon this fubject. They have confidered the topics of argumentation as reducible to certain axioms. For inftance, when the question is about the genus of a thing, it must be determined by fome axiom about genus and fpecies; when it is about a definition, it must be determined by fome axiom relating to definition, and things defined: and fo of other questions. VOL. III. 3 E They

They have therefore reduced the doctrine of the topics to certain axioms or canons, and difpofed these axioms in order under certain heads.

This method feems to be more commodious and elegant than that of Ariftotle. Yet it must be acknowledged, that Ariftotle has furnished the materials from which all the logicians have borrowed their doctrine of topics: and even Cicero, Quintilian, and other rhetorical writers, have been much indebted to the topics of Aristotle.

He was the first, as far as I know, who made an attempt of this kind and in this he acted up to the magnanimity of his own genius, and that of ancient philofophy. Every subject of human thought had been reduced to ten categories; every thing that can be attributed to any subject, to five predicables: he attempted to reduce all the forms of reasoning to fixed rules of figure and mode, and to reduce all the topics of argumentation under certain heads; and by that means to collect as it were into one store all that can be faid on one fide or the other of every question, and to provide a grand arsenal, from

which all future combatants might be furnifhed with arms offenfive and defenfive in every caufe, fo as to leave no room to future generations to invent any thing

new.

The last book of the Topics is a code of the laws according to which a fyllogistical difputation ought to be managed, both on the part of the affailant and defendant. From which it is evident, that this philofopher trained his disciples to contend, not for truth merely, but for victory.

SECT. 3. Of the book concerning Sophifms.

A fyllogifm which leads to a falfe conclufion, must be vicious, either in matter or form for from true principles nothing but truth can be justly deduced. If the matter be faulty, that is, if either of the premises be falfe, that premise must be denied by the defendant. If the form be faulty, fome rule of fyllogifm is tranfgreffed; and it is the part of the defendant to fhew, what general or special rule it is that is tranfgreffed. So that, if he be an able logician, he will be impregnable in the 3 E 2 defence

defence of truth, and may resist all the attacks of the fophift. But as there are syllogifms which may feem to be perfect both in matter and form, when they are not really fo, as'a piece of money may feem to be good coin when it is adulterate; fuch fallacious fyllogifms are confidered in this treatife, in order to make a defendant more expert in the use of his defenfive weapons.

And here the author, with his ufual magnanimity, attempts to bring all the fallacies that can enter into a fyllogifm under thirteen heads; of which fix lie in the diction or language, and feven not in the diction.

The fallacies in diction are, 1. When an ambiguous word is taken at one time in one fenfe, and at another time in another. 2. When an ambiguous phrafe is taken in the fame manner. 3. and 4. are ambiguities in fyntax; when words are conjoined in fyntax that ought to be disjoined; or disjoined when they ought to be conjoined. 5. is an ambiguity in profody, accent, or pronunciation. 6. An ambiguity arifing from fome figure of fpeech.

When