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SECTION IV.

The Consideration of the Inductive Logic resumed.

I.

Additional Remarks on the distinction between Experience and Analogy. Of the grounds afforded by the latter for Scientific Inference and Conjecture.

IN the same manner in which our external senses are struck with that resemblance between different individuals which gives rise to a common appellation, our superior faculties of observation and reasoning, enable us to trace those more distant and refined similitudes which lead us to comprehend different species under one common genus. Here, too, the principles of our nature, already pointed out, dispose us to extend our conclusions from what is familiar to what is comparatively unknown; and to reason from species to species, as from individual to individual. In both instances, the logical process of thought is nearly, if not exactly the same; but the common use of language has established a verbal distinction between them; our most correct writers, being accustomed (as far as I have been able to observe) to refer the evidence of our conclusions, in the one case, to experience, and in the other to analogy. The truth is, that the difference between these two denominations of evidence, when they are accurately analyzed, appears manifestly to be a difference, not in kind, but merely

in degree; the discriminative peculiarities of individuals invalidating the inference, as far as it rests on experience solely, as much as the characteristical circumstances which draw the line between different species and different genera

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This difference in point of degree (it must at the same time be remembered) leads, where it is great, to important conse

* In these observations on the import of the word analogy, as employed in philoso phical discussions, it gives me great pleasure to find, that I have struck nearly into the same train of thinking with M. Prévost. I allude more particularly to the following passage in his Essais de Philosophie.

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"Le mot Analogie, dans l'origine, n'exprime que la ressemblance. Mais l'usage l'applique à une ressemblance éloignée: d'ou vient que les conclusions analogiques sont "souvent hasardées, et ont besoin d'être déduites avec art. Toutes les fois donc que, "dans nos raisonnemens, nous portons des jugemens semblables sur des objets qui n'ont qu'une ressemblance éloignée, nous raisonnons analogiquement. La ressemblance pro"chaine est celle qui fonde la première généralisation, celle qu'on nomme l'espèce. On "nomme éloignée la ressemblance qui fonde les généralisations superieures, c'est-à-dire, "le genre et ses divers degrès. Mais cette definition n'est pas rigoureusement suivie. "Quoiqu'il en soit, on conçoit des cas, entre lesquels la ressemblance est si parfaite, qu'il ne s'y trouve aucune différence sensible, si ce n'est celle du tems et du lieu. Et "il est des cas dans lesquels on apperçoit beaucoup de ressemblance, mais où l'on decouvre aussi quelques différences indépendantes de la diversité du temps et du lieu. "Lorsque nous ferons un jugement general, fondé sur la première espèce de ressem"blance, nous dirons que nous usons de la méthode d'induction. Lorsque la seconde espèce de ressemblance autorisera nos raisonnemens, nous dirons que c'est de la mé"thode d'analogie que nous faisons usage. On dit ordinairement que la méthode d'in"duction conclut du particulier au général, et que la methode d'analogie conclut du "semblable au semblable. Si l'on analyse ces definitions, on verra que nous n'avons "fait autre chose que leur donner de la précision." (Essais de Philosophie, Tome II. p. 202.)

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See also the remarks on induction and analogy in the four following articles of M. Prevost's work.

quences. In proportion as the resemblance between two cases diminishes in the palpable marks which they exhibit to our senses, our inferences from the one to the other are made with less and less confidence; and therefore it is perfectly right, that we should reason with more caution from species to species, than from individual to individual of the same kind. In what follows, accordingly, I shall avail myself of the received distinction between the words experience and analogy; a distinction which I have hitherto endeavoured to keep out of view, till I should have an opportunity of explaining the precise notion which I annex to it. It would, in truth, be a distinction of important use in our reasonings, if the common arrangements, instead of originating, as they have often done, in ignorance or caprice, had been really the result of an accurate observation and comparison of particulars. With all the imperfections of these arrangements, however, a judicious inquirer will pay so much regard to prevailing habits of thinking, as to distinguish very scrupulously what common language refers to experience from what it refers to analogy, till he has satisfied himself, by a diligent examination, that the distinction has, in the instance before him, no foundation in truth. On the other hand, as mankind are much more disposed to confound things which ought to be distinguished, than to distinguish things which are exactly or nearly similar, he will be doubly cautious in concluding, that all the knowledge which common language ascribes to experience is equally solid; or that all the conjectures which it places to the account of analogy are equally suspicious.

A different idea of the nature of analogy has been given by some writers of note; and it cannot be denied, that, in certain instances, it seems to apply still better than that proposed above. The two accounts however, if accurately analyzed, would be found to approach much more nearly, than they appear to do at first sight; or rather, I am inclined to think, that the one might be resolved into the other, without much straining or over refinement. But this is a question chiefly of speculative curiosity, as the general remarks which I have now to offer, will be found to hold with respect to analogy, considered as a ground of philosophical reasoning, in whatever manner the word is defined; provided only it be understood to express some sort of correspondence or affinity between two subjects, which serves, as a principle of association or of arrangement, to unite them together in the mind.

According to Dr Johnson, (to whose definition I allude more particularly at present) analogy properly means "a re"semblance between things with regard to some circumstances

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or effects; as when learning is said to enlighten the mind ;— "that is, to be to the mind what light is to the eye, by enabling "it to discover that which was hidden before." The statement is expressed with a precision and justness not always to be found in the definitions of this author; and it agrees very nearly with the notion of analogy adopted by Dr Ferguson,-that" things which have no resemblance to each "other may nevertheless be analogous; analogy consisting "in a resemblance or correspondence of relations *." As

* Principles of Moral and Political Science. Vol. I. p. 107.

an illustration of this, Dr Ferguson mentions the analogy between the fin of a fish and the wing of a bird; the fin bearing the same relation to the water, which the wing does to the air. This definition is more particularly luminous, when applied to the analogies which are the foundation of the rhetorical figures of metaphor and allusion; and it applies also very happily to those which the fancy delights to trace between the material and the intellectual worlds; and which (as I have repeatedly observed), are so apt to warp the judgment in speculating concerning the phenomena of the human mind.

The pleasure which the fancy receives from the contemplation of such correspondences, real or supposed, obviously presupposes a certain disparity or contrast in the natures of the two subjects compared; and, therefore, analogy forms an associating principle, specifically different from resemblance, into which Mr Hume's theory would lead us to resolve it. An additional proof of this is furnished by the following consideration, That a resemblance of objects or events is perceived by sense, and accordingly has some effect even on the lower animals; a correspondence (or, as it is frequently called, a resem blance) of relations, is not the object of sense, but of intellect, and consequently, the perception of it implies the exercise of

reason.

Notwithstanding, however, the radical distinction between the notions expressed by the words resemblance and analogy, they may often approach very nearly to each other in their meaning; and cases may even be conceived in which they ex

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