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their own sentiments upon this point, may easily satisfy themselves one way or other, by reading, in the first place, the third book de Augmentis Scientiarum. In this they will find a formal exposition of Bacon's views de Doctrinâ Naturæ. The sketch which is contained in this book of his opinions upon the subject in general, may afterwards be filled up by reference to his Novum Organon, lib. i. aph. 66, 75. Lib. ii. aph. 2, 4, 5, 17, 27, 40. To which may
be added some remarks in his Natural History, cent. ix. at the beginning; also Natural History, cent. ix. Sect. 846. Cent. x. Sect. 960. Nor should we omit a short summary of the objects of philosophy placed after his New Atlantis entitled · Magnalia Naturæ præcipue quoad Usus humanos;' also a Letter to his friend Matthews, marked CÍl in the folio edition, 1780. As the decision of this question is, however, of no importance in a philosophical point of view, we shall now present our readers with our author's explanations of the inductive process. As. it is extremely clear and able, we shall give it in his own words:
* As we can in no instance perceive the link by which two successive eyents are connected, so as to deduce, by any reasoning, a priori, the one from the other as a consequence or effect, it follows, that when we see an event take place which has been preceded by a combination of different circumstances, it is impossible for human sagacity to ascertain whether the effect is connected with all the circumstances or only with part of them; and (in the latter supposition) which of the circumstances is essential to the result, and which are merely accidental accessories or concomitants. The only way, in such a case, of coming at the truth is to repeat over the experiment again and again, leaving out all the different circumstances successively, and observing with what particular combinations of them the effect is conjoined. If there be no possibility of making this separation, and if, at the same time, we wish to obtain the same result, the only method of ensuring success is to combine together all the various circumstances which were united in our former trials. When, by thus comparing a number of cases, agreeing in some circumstances, but differing in others, and all attended with the same result, a philosopher connects, as a general law of nature, the event with its physical cause, he is said to proceed according to the method of induction.'-330.
To this explanation of the nature of the inductive process we have nothing to object, but on the contrary are happy in an opportunity of recommending it to the attention of our readers as by much the best which we have met with ; not excepting Bacon's own; but with respect to Mr. Stewart's opinions as to the grounds upon which the mind reposes its confidence in the general truth of the result, we feel a very considerable degree of hesitation indeed. He tells us, that in this we are guided merely by an instinctive expectation of the continuance of the laws of nature;' to which
expectation expectation Dr. Reid, long ago, gave the name of the inductive principle; he continues,
• In all Bacon's logical rules the authority of this law of belief is virtually recognized, although it is only of late that natural philosophers have been fully aware of its importance as the groundwork of the inductive logic. Dr. Reid and M. Turgot were, as far as I know, the first who recognized its existence as an original and ultimate law of the understanding; the source of all that experimental knowledge which we begin to acquire from the moment of our birth, as well as of those more recondite discoveries which are dignified by the name of science, It is but justice to Mr. Hume to acknowledge that his Treatise of Human Nature furnished to Dr. Reid all the premises from which his conclusions were drawn; and that he is therefore fairly entitled to the honour of having reduced logicians, to the alternative of either acquiescing in his sceptical conclusions, or of acknowledging the authority of some instinctive principles of belief overlooked in Locke's Essay-332.
We cannot help thinking that our author is here giving to the reasoning of Mr. Hume upon this important question, a degree of rank to which it is by no means very certainly entitled; as to the name of M. Turgot it can be introduced merely as an argumentum ad verecundiam, because the doctrine, which is above alluded to, is only stated historically by his biographer Condorcet, as an opinion which the former entertained. With regard to Dr. Reid, he invariably refers his readers, as does Mr. Stewart likewise, to
the unanswerable arguments' of Mr. Hume, thus laying upon this last ingenious writer, the whole onus probandi of one of the strangest, and we are inclined to think, one of the most untenable paradoxes that ever has been started.
In order that our readers may be aware of the full import of the doctrine which our author seems to think so incontrovertible, and upon which he professes to have erected the whole fabric of his philosophy, we must refer them to Chap. I. Sect. 2, of his first volume.
• The natural bias of the mind,' says he, “is surely to conceive physical events as somehow linked together, and material substances as possessed of certain powers and virtues which fit them to produce particu. lar effects. That we have no reason to believe this to be the case has been shewn in a very particular manner by Mr. Hume and by other writers; and must indeed appear evident to every person on a moment's reflection. It is a curious question what gives rise to this prejudice.'
We certainly so far agree with our author as to admit that there is no doubt a natural bias in the mind to conceive material substances as possessed of certain powers which fit them to produce particular effects;' that is, to suppose fire as possessing a power to burn, and bread to nourish; and truly were it any other person than Mr. Stewart who is speaking, we should have supposed that he must intend to be facetious, when he tells us that it must appear evident to every person on a moment’s reflection, that we have no reason whatever to believe in what would seem to be, at first sight, so very undoubted a fact. To this cavalier sort of argument we can make no reply; and as Mr. Stewart adduces no other that we are aware of, except a general reference to Mr. Hume's, it is against the reasoning of this last very paradoxical person that we shall propose, in the first place, the objections which we have to offer. It was the opinion of Mr. Hume, that since the origin of our ideas is plainly ascribable, in the first instance, to the exercise of our external senses, all the objects of our knowledge must either be some impression upon our organs of sense, or some copy from these impressions in the imagination. Accordingly whenever we meet with any idea, the original of which cannot be recognized among some of our sensations, he directs us to dismiss such idea as false and impossible. If we adopt this rule, it will easily be perceived, that we can have no idea whatever of efficient causes or of the secret processes by which any effects may be produced. Mr. Hume, therefore, examines what principle of the mind it is by which“ from causes which appear similar we are led to expect similar results.' Had this expectation been founded upon reason, he affirms that it would have been as perfect at once and after one instance, as after ever so long a course of experience;' since this, however, seems not, he thinks, to be the case, he decides by resolving this expectation into ' habit or custom ; for, as he observes,
i whenever the repetition of any particular act or operation produces a propensity to renew the same act or operation without being impelled by any reasoning or process of the understanding, we always say that this propensity is the effect of custom.'
To the first part of this reasoning it is not necessary that we should say anything; it is founded upon a theory which Mr. Stewart dissents from and which is certainly untenable. We admit, however, that, according to the meaning of Mr. Hume, we have no knowledge of efficient causes, that is to say, no knowledge of the necessary connection between these and the effects which they produce, nor of the secret processes by which they operate. But this is not the question; the point at issue between Mr. Hume and those who differ with him, is not whether we have
such knowledge as this, which we clearly have not, but whether when we ascribe any effect to a particular cause, or when we judge that material substances will continue to retain the properties which they now possess, these opinions are derived from reason or from custom; which last Mr. Hume agrees with our author in believing to be one of those natural instincts which no reasoning, or process
thought, or the understanding, is able either to produce or to prevent.'
Now that custom is not the name of the instinct by which the fact in question can be accounted for, is so extremely evident that we are altogether at a loss to conceive how the fallacy of such a supposition could have escaped the penetration of two such acute writers as Dr. Reid and our author. Custom, according to the very words of Mr. Hume's own definition, can be adduced in explanation only of the propensity to renew any act or operation; in the present instance, therefore, the habit in question presupposes the fact of our belief, and upon any supposition can do no more than point out the principle by which it may be renewed in the mind without any intervening act of reflection. This seems to us so plain and incontrovertible as to need no farther illustration.
It does not however follow, that because the phenomenon under consideration is not to be explained by custom, it can therefore be accounted for from reason; it may, for any thing that has yet been said, be founded upon the instinct which Dr. Reid denominates the inductive principle of our nature. As we candidly confess that we are not able to attach any explicit meaning to this last phrase such as we attach to the word custom, it will be in our power to controvert this position only by establishing its contrary,
The question as to the foundation of our belief in matters of fact, may be considered under two heads, which, however intimately connected in their principles, are yet distinguishable in themselves; these are, why we conclude that the things which now exist will continue to exist in future; and continuing to exist, why we suppose that they will retain the same properties. Both these questions may be very briefly and we think very satisfactorily answered. With respect to the first, we may observe that the maxim de nihilo nihil fit, is one which it plainly involves a speculative absurdity to deny. Accordingly Dr. Reid enumerates among what he calls the first principles of necessary truths,' that every thing which has had a beginning must have had a cause.
It is however perfectly obvious, that to suppose any thing to become annihilated without a cause, is just as impossible as to conceive its being produced without one; and consequently no such cause being perceived or apprehended, our reason necessarily infers, upon the principles of Dr. Reid himself, that whatever now exists, will continue to exist in some shape or other, until the same Almighty hand that called it into being shall be pleased in like manner to recall it from existence. It was precisely this sort of inference which led Sir Isaac Newton to enumerate among the selfevident principles of his Natural Philosophy, that a body being in motion will continue to move forward in a right line until acted upon by some external force. It is plain that he deduced this law neither from experience nor custom, nor instinct, but because to suppose the contrary seemed to him plainly repugnant to the first dictates of reason. And the proof given by D'Alembert, of its truth, is altogether founded upon the general reasoning, which we have just alluded to; if no cause exists, says he, why a body in motion should turn either to the right or to the left, nor why it should cease to move, it will necessarily do neither, but continue to move forward in the line of its first direction to all eternity
Admitting then that our reason necessarily infers that whatever now exists will continue to exist in some shape or other until some cause appear to the contrary, it may be asked, But why do we conclude that it will continue to retain the same nature and properties? This question is, in substance, already answered ; it may however be farther observed, that the existence of material substances being supposed, the relations in which they stand towards each other, are obviously just as absolute with respect to us, as those which we trace among merely speculative truths; the only difference of the two cases is, that the former depend for their continuance upon a contingency, whereas the latter are, in their nature, immutable and eternal.
It is true, that to conceive the metaphysical properties of space. and number, as being otherwise than we find them, is absolutely impossible; whereas had it so pleased our Maker, the fragrance of a rose might have excited a sensation of pain instead of pleasure, and the bread which we eat have afforded a poison instead of nourishment; but having created us what we are, and having made the things around us what they are, not omnipotence itself could change the various relations which exist between material substances them selves, or between them and us, without altering the nature of those properties with which we and they are respectively endowed.
Accordingly when we conclude that the things which now exist, will continue to exist, and that continuing to exist they will retain the same properties, we do not mean that every red and undulating appearance is flame, nor that every whitish farinaceous-looking substance is bread; but our own constitution, and the things around us, remaining unaltered, (and, no cause to the contrary being assigned, we can have no reason to expect that they will not,) we infer generally, that the same substances which burn or nourish us to day, will continue to do the same in future. It is
upon this principle that Locke explains the general knowledge which particular demonstrations in mathematics afford. "The immutability of the same relations between the same immutable things shews, that if the three angles of a triangle were once equal to two right angles, they will always be equal to two right angles.'