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επιστήμη λογική, or Iogical science ; also τέχνη λογική, or logical art. The adjective loyikń, being used alone, soon came to be the name of the science, just as Mathematic, Rhetoric, and other names ending in “ic” were originally adjectives but have been converted into substantives.
Much discussion of a somewhat trifling character has arisen upon the question whether Logic should be considered a science only, an art only, or both at the same time. Sir W. Hamilton has even taken the trouble to classify almost all the writers on logic according as they held one opinion or the other. But it seems substantially correct and sufficient to say, that logic is a science in so far as it merely investigates the necessary principles and forms of thought, and thus teaches us to understand in what correct thinking consists; but that it becomes an art when it is occupied in framing rules to assist persons in detecting false reasoning. A science teaches us to know and an art to do, and all the more perfect sciences lead to the creation of corresponding useful arts. Astronomy is the foundation of the art of navigation on the ocean, as well as of the arrangement of the calendar and chronology. Physiology is the basis of the art of medicine, and chemistry is the basis of many useful arts. Logic has similarly been considered as the basis of an art of correct reasoning or investigation which should teach the true method to be observed in all sciences. The celebrated British logician Duns Scotus, who lived in the 13th century, and called logic the Science of Sciences, called it also the Art of Arts, expressing fully its preeminence. Others have thus defined it—" Logic is the art of directing the reason aright in acquiring the knowledge of things, for the instruction both of ourselves and others.”' Dr Isaac Watts, adopting this view of logic, called his well-known work “the Art of Thinking.”
It may be fairly said however that Logic has more the form of a science than an art for this reasonall persons necessarily acquire the faculty and habit of reasoning long before they even know the name of logic. This they do by the natural exertion of the powers of mind, or by constant but unconscious imitation of others. They thus observe correctly but unconsciously the principles of the science in all very simple cases; but the contradictory opinions and absurd fallacies which are put forth by uneducated persons shew that this unaided exercise of mind is not to be trusted when the subject of discussion presents any difficulty or complexity. The study of logic then cannot be useless. It not only explains the principles on which every one has often reasoned correctly before, but points out the dangers which exist of erroneous argument. The reasoner thus becomes consciously a correct reasoner and learns consciously to avoid the snares of fallacy. To say that men can reason well without logical science is about as true as to say that they can live healthily without medicine. So they can—as long as they are healthy; and so can reasoners do without the science of reasoning—as long as they do reason correctly; but how many are there that can do so? As well might a man claim to be immortal in his body as infallible in his mind.
And if it be requisite to say a few words in defence of Logic as an art, because circumstances in the past history of the science have given rise to misapprehension, can it be necessary to say anything in its praise as a science? Whatever there is that is great in science or in art or in literature, it is the work of intellect. In bodily form man is kindred with the brutes, and in his perish. able part he is but matter. It is the possession of conscious intellect, the power of reasoning by general notions that raises him above all else upon the earth; and who
can say that the nature and procedure of this intellect is not almost the highest and most interesting subject of study in which we can engage? In vain would any one deny the truth of the favourite aphorism of Sir W. Hamilton
IN THE WORLD THERE IS NOTHING GREAT BUT MAN. IN MAN THERE IS NOTHING GREAT BUT MIND.
THE THREE PARTS OF LOGICAL DOCTRINE.
It has been explained in the previous lesson that Logic is the Science of Reasoning, or the Science of those Necessary Laws of Thought which must be observed if we are to argue consistently with ourselves and avoid selfcontradiction. Argument or reasoning therefore is the strictly proper subject before us. But the most convenient and usual mode of studying logic is to consider first the component parts of which any argument must be made up. Just as an architect must be acquainted with the materials of a building, or a mechanic with the ma. terials of a machine, before he can pretend to be acquainted with its construction, so the materials and instruments with which we must operate in reasoning are suitably described before we proceed to the actual forms of argument.
If we examine a simple argument such as that given in the last lesson, thus
Iron is a metal,
Every metal is an element, Therefore Iron is an element,
we see that it is made up of three statements or assertions, and that each of these contains, besides minor words, two nouns substantive or names of things, and the verb “is.” In short, two names, or terms, when connected by a verb, make up an assertion or proposition; and three such propositions make up an argument, called in this case a syllogism. Hence it is natural and convenient first to describe terms, as the simplest parts; next to proceed to the nature and varieties of propositions constructed out of them, and then we shall be in a position to treat of the syllogism as a whole. Such accordingly are the three parts of logical doctrine.
But though we may say that the three parts of logic are concerned with terms, propositions, and syllogisms, it may be said with equal or greater truth that the acts of mind indicated by those forms of language are the real subject of our consideration. The opinions, or rather perhaps the expressions, of logicians have varied on this point. Archbishop Whately says distinctly that logic is entirely conversant about language; Sir W. Hamilton, Mr Mansel, and most other logicians treat it as concerned with the acts or states of mind indicated by the words; while Mr J. S. Mill goes back to the things themselves concerning which we argue. Is the subject of logic, then, language, thought, or objects ? The simplest and truest answer is to say that it treats in a certain sense of all three. Inasmuch as no reasoning process can be explained or communicated to another person without words, we are practically limited to such reasoning as is reduced to the form of language. Hence we shall always be concerned with words, but only so far as they are the instruments for recording and referring to our thoughts. The grammarian also treats of language, but he treats it as language merely, and his science terminates with the description and explanation of the forms, varieties, and
relations of words. Logic also treats of language, but only as the necessary index to the action of mind.
Again, so long as we think correctly we must think of things as they are; the state of mind within us must correspond with the state of things without us whenever an opportunity arises for comparing them. It is impossible and inconceivable that iron should prove not to be an elementary substance, if it be a metal, and every metal be an element. We cannot suppose, and there is no reason to suppose, that by the constitution of the mind we are obliged to think of things differently from the manner in which they are. If then we may assume that things really agree or differ according as by correct logical thought we are induced to believe they will, it does not seem that the views of the logicians named are irreconcileable. We treat of things so far as they are the objects of thought, and we treat of language so far as it is the embodiment of thought. If the reader will bear this explanation in mind, he will be saved from some perplexity when he proceeds to read different works on logic, and finds them to vary exceedingly in the mode of treatment, or at least of expression.
If, when reduced to language, there be three parts of logic, terms, propositions, and syllogisms, there must be as many different kinds of thought or operations of mind. These are usually called
1. Simple apprehension,
3. Reasoning or discourse. The first of these, Simple Apprehension, is the act of mind by which we merely become aware of something, or have a notion, idea, or impression of it brought into the mind. The adjective simple means apart from other things, and apprehension the taking hold by the mind. Thus the name or term Iron instantaneously makes the