SECTION I. THE NAME AND NATURE OF THE ART OF REASONING. THE art of reasoning is called Logic. But you know Shakspeare has said— "What we call a Rose, By any other name would smell as sweet." In the present case we have no occasion for any name. We might simply say the "Art of Reasoning." In the same way we say the art of nursing, the art of teaching, the art of dancing, or the art of fencing. Had either of these arts a Greek name, a writer would begin his treatise with stating the meaning of this name; and probably learned men would differ as to the propriety and extent of its application. There is, however, a convenience in giving distinct names to distinct branches of knowledge. But have a care of supposing that because an art or a science has got a hard name, there must be something very difficult in the art or science itself. Many of our arts and sciences were taught by the Greeks, and when our learned men first wrote upon them in English, they very naturally called them by their Greek names. Thus, the word logic is derived from a Greek word (logos) that signifies discourse. But these words have no natural connexion with the arts and sciences to which they are applied. You will have made no unimportant step in a knowledge of the art of reasoning, when you at all times recollect that the names of things are quite distinct from the things themselves. All the processes of reasoning can be as clearly described in "Household Words " as in those Greek words in which they are usually expounded. To reason clearly and forcibly, it is not necessary that you should understand any other language than your own. 66 Argumentation or reasoning," says Dr. Watts, "is that operation of the mind, whereby we infer one thing, that is, one proposition, from two or more propositions premised.* Or it is the drawing a conclusion, which before was either unknown, or dark, or doubtful, from some propositions which are more known and evident. So when we have judged that matter cannot think, and that the mind of man doth think, we then infer and conclude, that therefore the mind of man is not matter. "So we judge that a just governor will make a difference between the evil and the good; we judge also that God is a just governor; and from thence we conclude, that God will make a difference between the evil and the good. "This argumentation may be carried on further, thus: God will one time or another make a difference between the good and the evil; but there is little or no difference made in this world; therefore there must be another world wherein this difference shall be made. "These inferences or conclusions are the effects of reasoning, and the three propositions taken all together are called a syllogism or argument." "Archbishop Whately," observes Mr. Mill, "has defined logic to be the science as well as the art of reasoning, meaning by the former term the analysis of the mental process which takes place whenever we reason; and by the latter the rules grounded upon that analysis for conducting the process correctly. "Logic then comprises the science of reasoning, as well as an art founded on that science. But the word reasoning, like most other scientific terms in popular use, abounds in ambiguities. In one of its acceptations it means syllogising; in another of its senses, to reason is simply to infer any assertion from assertions already admitted. The latter and more extensive signification is that in which I mean to use it.* "Our object will be to attempt a correct analysis of the intellectual process called reasoning or inference, and of such other mental operations as are intended to facilitate this, as well as on the foundation of this analysis, and pari passu with it, to bring together or frame a set of "I am myself disposed to think that any fact which can be shown to be implied or contained in another fact may conveniently and properly be said to be inferred from it, and that the process may be with equal convenience and propriety termed reasoning."-Bailey's Theory of Reasoning, p. 41. rules or canons for testing the sufficiency of any given evidence to prove any given proposition." The reader will perceive that Mr. Mill's book is written on the science of reasoning. Our book is written on the art of reasoning. We use the word reasoning in the wider sense used by Mr. Mill, and as including what is denoted by arguing, proving, inferring, confirming, refuting, and all similar words, in the sense in which they are popularly understood. A knowledge of the art of reasoning is essential to the study of the science; but an acquaintance with the science is not necessary to the practice of the art. Indeed it is only by the use of the art that the science can be studied. We meddle not with the science. profess not to analyse any of the powers of the mind, nor to lay down any new rules for conducting the process of reasoning. We shall attempt only to describe those rules that are already known, and to apply them correctly. And we shall consider their application chiefly with reference to those things with which people are most familiar. We If a man who understands grammar hear a person say, "I speaks," he will know, from general practice, that the language is improper; but he will, moreover, quote the rule, that "a verb should agree with its nominative case in number and person." Now, a collection of such rules form grammar, or the art of speaking correctly. So, if a man hear a person say-" All men are liars, for a party has just told me a lie," he will know from his own common sense that this is not sound reasoning; but if he has studied logic, he will also cite the rule, "Universals cannot be inferred from particulars." Now, a collection of all these rules form logic, or the art of reasoning correctly; and the man who has a knowledge of these rules, and is correct and ready in applying them in practice, is called a logician. A man may reason accurately without rules. But if he can give the rules, he will have more confidence in the truth of his reasonings. He will also be better able to perceive the incorrect reasonings of others, and to show the soundness or unsoundness of any opinions propounded for his consideration. These practical rules of reasoning collected together form the art of reasoning, in the same way as a collection of rules for speaking and writing with propriety form the art of speaking and writing with propriety. The one art is called logic-the other art is called grammar. These two arts are useful to each other. Thoughts are expressed in words. If we think clearly we shall speak clearly, and when we are learning to arrange our words with accuracy and order, we are learning to think with accuracy and order. A person who has acquired a knowledge of grammar will afterwards speak and write grammatically, without ever thinking of the rules of grammar. So a person who has acquired a knowledge of logic, will afterwards reason logically, without ever thinking of the rules of logic. The rules will have become so deeply fixed in his mind that he will habitually reason accurately; and by practice he will come to reason promptly and forcibly. It is the chief business both of grammar and logic to teach us how to avoid errors. Grammar teaches us how to avoid the use of words and sentences that are contrary to its rules. But a beautiful or powerful style of writing must arise from the constitution of our own minds, or the peculiar direction of our studies, and is not to be acquired merely by an observance of grammatical construction. So logic teaches how to know and to discard bad arguments. To be able to reason promptly and forcibly, depends upon our attainments in knowledge-the constitution of our mental powers -the extent of our practice-and the degree with which we are familiar with the writings of those learned men who are celebrated as the masters of the art of reasoning. Dr. Campbell, in his Philosophy of Rhetoric, compares logic to the soul, and grammar to the body; the union of both being essential to an excellent discourse. SECTION II. THE SUBJECTS OF THE ART OF REASONING. It THE human mind can think, can reason, can remember. The mind may think of things without reasoning about them; and it may remember things without reasoning about them. We shall in this section take a view of those truths with which we become acquainted by other means than reasoning. They may be classed into truths of the sensestruths of consciousness-truths of the intellect—and truths of testimony. On these topics we shall quote Dr. Watts. 1. Truths of the senses : "The evidence of sense is, when we frame a proposition according to the dictates of any of our senses; so we judge that grass is green; that a trumpet gives a pleasant sound; that fire burns wood; water is soft; and iron is hard; for we have seen, heard, or felt all these. It is upon this evidence of sense that we know and believe the daily occurrences in human life; and almost all the histories of mankind, that are written by eye or ear-witnesses, are built upon this principle. "Under the evidence of sense we do not only include that knowledge which is derived to us by our outward senses of hearing, seeing, feeling, tasting, and smelling; but that also which is derived from the inward sensations and appetites of hunger, thirst, ease, pleasure, pain, weariness, rest, &c., and all those things which belong to the body; as, 'hunger is a painful appetite; light is pleasant; rest is sweet to the weary limbs." " 2. Truths of consciousness :— "As we learn what belongs to the body by the evidence of sense, so we learn what belongs to the soul by an inward consciousness, which may be called a sort of internal feeling, or spiritual sensation of what passes in the mind; as, ‘I think before I speak; I desire large knowledge; I suspect my own practice; I studied hard to-day; my conscience bears witness of my sincerity; my soul hates vain thoughts; fear is an uneasy passion; long meditation on one thing is tiresome.' "Thus it appears that we obtain the knowledge of a multitude of propositions, as well as of single ideas, by those two principles which Mr. Locke calls sensation and reflection; one of them is a sort of consciousness of what affects the body, and the other is a consciousness of what passes in the mind.” 3. Truths of the intellect : "Intellect relates chiefly to those abstracted propositions which carry their own evidence with them, and admit no doubt about them. Our perception of this self-evidence in any proposition is called intelligence. It is our knowledge of those first principles |