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ART. IV.-MILL AND WHEWELL ON THE LOGIC OF INDUCTION.

1. A System of Logic, Ratiocinative and Inductive, being a connected View of the Principles of Evidence and the Methods of Scientific Investigation. By John Stuart Mill. In 2 vols. Second Edition. London: John W. Parker, West Strand. 1846. Book III. Of Induction.

2. Of Induction; with especial reference to Mr. John Stuart Mill's System of Logic. By W. Whewell, D.D., Author of the "History and Philosophy of the Inductive Sciences." London: John W. Parker, West Strand.

1849.

It is not without reason, that original speculation in physical and metaphysical science is so seldom pursued with any very considerable success by the same mind. The process by which laws of nature are first detected, differs in one respect so essentially from that which attempts the analysis of mental phenomena, that the very habits of thought most favourable to the physical discoverer may only impede or defeat the efforts of the mental philosopher. The difference alluded to is this, that while we can recognise no ties of necessary connection between the causes and effects of the physical world, mental investigations are performed on our own minds, through the agency of a conscious reflection, which brings conviction in the very process of a true analysis, without waiting for the subsequent verifications from experience. All proofs of physical connection are only indirect; the hypothetical causes having no intrinsic evidence in their favour, but owing their reception either to the absence of any other possible cause, or to the overwhelming presumption afforded by new and correct inferences that verify the guess; but antecedent to all verification, or rather as its verification, the mental philosopher has the evidence of his own consciousness as to whether his analysis be correct: the cause and consequence being connected in the same fact of

consciousness, he has with him the same kind of intrinsic evidence that belongs to deductive reasoning; he can tell at once whether it could or could not produce a similar effect, without recourse to experiment;--he carries some criteria of truth along with him even while he reasons, and so accustoms his mind to expect at once at least apparent presumption, a conscious perception of some internal relation between the supposed cause and the effect, even before he begins to judge. The mind of the physical discoverer, on the other hand, must be governed chiefly by general and slight analogies in its first suspicions concerning causes; analogies drawn from the physical sciences themselves, and which would have no force with a mind not already familiar with the general resemblances that they afford. By the very same consciousness by which we are cognizant of a mental effect, we have also been cognizant of the mental antecedents which produced it; but when we perceive a physical effect, we have no data whatever given us to trace the history and mode of its formation. Hence the analysis of direct inspection which serves the mental philosopher, is wholly different in its requisites from the processes of physical investigation, and he who should take to it the habits of thought he had acquired from them, would miserably fail.

This remark may, perhaps, serve to explain why so eminent a scientific philosopher as Dr. Whewell has failed so remarkably in his attempt to create a philosophy of science; why the History of Physical Science, which he wrote with so much ability, prepared him so little to analyze its mental processes, and expound its logic. A study of sciences where the mind can discover no necessary connections between cause and effect, and has to look for the indications of probability, and follow out the traces of analogy, were but little likely to discipline a mind, apparently never very subtle or exact, for the close analysis of its own actions, and the detection of its own laws. Dr. Whewell could not have shown more completely his utter incompetency to estimate the difference in kind between the various sources of moral certainty, than by classing together, as he has done, the laws of motion and even the laws of chemical composition, with the truths of mathematics, and the variously stated principle of universal causa

tion itself. We regard it as unfortunate for the truth and perfectness of Mr. Mill's able work, that he should have had so feeble an antagonist (in its purely philosophical part) as Dr. Whewell. It will be said, perhaps, that Mr. Mill's powers of analysis might be regarded by his opponents with as little esteem as those of Dr. Whewell, because he also has classed a priori with a posteriori truths, referring them equally to the influence of constant association in experience: but there is this distinction. The theory which assigns experience and association as the source of all our knowledge, does at least provide for different gradations in moral certainty in proportion to the constancy and universality of experience; but those who would drag down all certainty to the level of empirical truths, who assign the highest degree of human certainty to the mere known succession of physical facts where no necessary connection can possibly be perceived, only show that they are utterly unable to estimate the highest degree of certainty at all, because they can discern within themselves no necessity of belief more stringent than the habits of thought which they have gained from their particular range of experience. While Mr. Mill does allow some room for our different degrees of conviction, by ascribing them entirely to various degrees in the uniformity of our experience, Dr. Whewell allows no such room, and thus puts it into Mr. Mill's power to use the very obvious argument, 66 as you show me what by necessary truths, by adducing what is to me entirely contingent, I am quite justified in finding for them the same source, which is, on all hands, allowed to be sufficient for the latter." However, we have no business, at present, with the controversy between Mr. Mill and Dr. Whewell, to which we have alluded; it is not touched upon in the pamphlet on Induction, in which Mr. Mill's book on that subject is criticized and replied to; and only in connection with the inductive canons which Mr. Mill has reduced to system from Sir John Herschel's little book, will it be requisite to consider how far Mr. Mill has established a consistent theory of causation as their basis. These remarks have been made, however, to illustrate the degree of philosophical sensitiveness which we may expect to find in the minds of our authors. Dr.

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Whewell's mind is better fitted, as it seems to us, for an inductive philosopher, than for a philosopher of induction; he examines mental processes as he would physical facts, and seems to aim only at giving an account which would describe them, not putting his mind into them to tell how they do really arise within; he regards them like an observer, ab extra, as needing classification and explanation, but does not take his own consciousness through the actual history of their formation, and so has no sensitiveness as to the different relations of kind, and internal authority, in which they stand to his own judgment. Mr. Mill's intellect, on the other hand, is one subtle enough in analysis, and that delights in deductive inference, but which can yield no belief to anything that is not capable either of direct perception, or of stringent deduction from facts of direct perception. He is inclined, therefore, to attribute any degree of influence to known causes, i. e. to facts capable of direct observation, rather than to assume any, even the slightest, cause, not capable of such perception, however perfectly it may account for the facts, and however disproportionate those facts may be to the hitherto observed results of any observed antecedents; in short, his tendency is rather to ascribe the very greatest degrees of influence to perceived causes, than the very smallest to those which are only assumed. Of this characteristic tendency in Mr. Mill's mind, his rejection of all a priori truth, his utilitarian creed in morals, his strong leaning to the doctrine that men's minds differ, not from different original constitution, but from the various influences to which they are subjected, and his remarks on Hypotheses, are perhaps sufficient indications. These remarks will make it clear why we cannot concur in Dr. Whewell's expectation that the Philosophy of Induction will become at all more lucid "in a controversial than in a didactic form," at least while the controversy is one between two minds so little able to catch each other's point of view; and while one of them monopolises nearly all the analytic power, so that he is confirmed rather than shaken in his own views by the learned, but ill-conceived, and ill-arranged objections of his opponent. In reviewing this controversy, therefore, we shall find it convenient to give first the theory of Mr. Mill, and in our review of that

theory to interweave the conflicting views (so far as they are systematic at all) maintained by Dr. Whewell.

At the very outset we are met with the question (so uniformly debated till a science has reached a very perfect state), what exactly are we to understand by the mental operation that is called Induction?-assuming meanwhile as a practical rule to guide us in seeking the answer to the question, that it is that operation (performed in all practical reasoning) by which we infer from particular data what is not contained either implicitly or explicitly therein, and what we cannot therefore arrive at by either deduction or analysis alone. Mr. Mill very properly therefore excludes from his definition of Induction, the formal syllogistic Induction, the raywyn of Aristotle, which gives no new inference, but only predicates in a fresh proposition of a whole class, what has been predicated severally of each individual contained in that class,— and also the deductive mathematical processes (as the formation of new terms in a series according to the analogy of the old) which only assume the appearance of Induction from the omission of a demonstration which might be supplied (viz., that successive terms must follow each other, according to the same law). Mr. Mill then goes on to exclude a process from Induction proper, which he afterwards places amongst the operations subsidiary to Induction, the process of combining, through some essential property common to them all, the particular facts or data from which the inference is to be drawn. Thus, for example, that all the observed points in a planet's motion are points in an ellipse of which one focus would represent the position of the sun, is only a description of observed facts, obtained by comparing them with the relative calculated positions of points in an ellipse; and as there is no new inference made here, but only a comparison between facts deduced from the laws of a mathematical curve, with facts noted by observation, Mr. Mill rightly denies to such a process the name of Induction.* This is however violently contested

* We may note that there is no dispute between Mr. Mill and Dr.Whewell as to the conclusions that the remaining unobserved points of the planet's orbit would also coincide with the ellipse, and that the planet would continue to move in the same ellipse. These are of course strictly inductive inferences, but so obvious, that Kepler's discovery is scarcely thought of as including them.

CHRISTIAN TEACHER.-No. 47.

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