A pure logic will all men to a metaphysic, for a pure logic has its use in its applications. A metaphysic, as a system, if it does not contain a logic, will lead to the results of most systems of metaphysic, that is, to none at all.
Thus it appears that the study of logic is perhaps the proper intro duction to a metaphysic ; and it were much to be wished that all who have written on the latter had first been subjected to the discipline of the former.
The forms of the Stu.00rsm are considered under that article, consistently with the plan of this work. In the mean time, till we have some system of logic in our language which is founded upon and grows out of 80111C philosophical system, it is better for the student to study only a purely formal logic, which is independent of any philoso phical system, and to apply it to his various studies.
The question, What is Logic I has been a matter of much dispute. It has been disputed 'whether logic is a science or an art, or both—an idle question, which may be safely left undecided. It is more im portant to determine what is comprehended in the term logic, and this has partly been attempted here. It is also of some importance to show that the notions of this science do not appear to have been very exact among the Greeks and Romans, which may be one cause of the traditional confusion as to the limits of logic, which has been so common in modern times. It may be also useful to show what logic is conceived to be by some modern writers.
There is no definition of logic in the extant works of Aristotle ; and if we deduce from his Organon, as we now have it, our notion of what the term comprehends, we shall find that it contains a great deal which does not belong to logic as it has been understood by those who have formed the most exact notions of it. If we should attempt to ascertain what logic is from the writings of all who have written ou logic, it will be found impossible to form any exact notion of its limits and objects.
Dialectic is distinguished by Cicero (` Topics; 2) from Topic. "All exact argumentation," he observes, "consists of two parts, one com prehending invention (unam inveniendi), and the other judgment (altemm judicandi)." He assigns to Aristotle pre-eminence in both, and speaks of the Stoics as having especially applied themselves to the latter, which they named Dialectic. But the dialectic of the Stoics was certainly not confined to pure logic, as appears from what Cicero says in his treatise ' On the Orator (ii. 38), and also from the statement of the Stoical opinions as to dialectic by Diogenes Laertius, in his Life of Zeno of Citium. The Stoic dialectic seems to have comprehended logic and more, as will hereafter appear; and yet it comprehended less than the logic of the l'eripateties.* In Dr. Whately's treatise, a-s may be collected from a comparison of various passages, logic seems to be convertible with syllogistic. To
reason, in the strict sense of the word, is to make use of arguments (p. 18); an argument, when regularly expressed, is a syllogism (p. 55); and logic is the science and the art of reasoning (p. 1); from which it follows that to syllogise and to reason are convertible, and that logic is the theory of the syllogism (p. 73).t This seems to be the meaning of the author, and if such be the proper notion of logic, it must be admitted that the boundaries of the science are very limited indeed. But limited as they really aro, in this view of the subject, the exercise of reducing argumentation to syllogistic forms still contains mere than those may be inclined to suppose who have not been disciplined in this practice.
It may be worth while to notice what Dr. Whatcly says of the word argument. argument," he observes, " consists of two parts, that which is proved, and that by means of which it is proved ;" and lie adds in a note, that this is the strict technical sense of the word argument, but that in popular use argument is often employed to denote the latter of these two parts alone. But this is a mistake : the popular use is the correct use, as it is in many other cases. When a man is said to use a good argument, he urges or suggests something which is either proved or universally admitted, and the goodness of his argument consists in its being applicable to the matter iu hand, and obviously comprehending within it something which it is his object to establish or prove. Ho who argues well, possesses the inventive faculty as defined by Cicero. It is his business to establish one or more things, and to command the assent of his hearers by presenting to their minds such propositions as only need to be presented in order to command assent, and which are comprehensive enough to embrace the particular things which he has to establish. The argument, in the popular sense, is the premises of the syllogism ; or it is the middle term ; and it is accordingly explained by Cicero (' Topics; 2) to be "ratio, guar rei dubire faciat fidem," the reason, which gives credibility to a thing that is doubtfuL Of course that which is proved, or to be proved, cannot be an argument within Cicero's meaning of the term. Dr. Whately himself says," that which is used to prove the question, if stated last (as is often done in common discourse), is called the reason." But it is equally the reason whether placed first or Last, and is called the reason with strict technical propriety, whatever may be the place which it occupies in discourse. The proper name for the syllogism is argumentation, of which the two premises are the argu ment; and this is the sense in which ancient logical writers under stood argumentation and argument.