Εικόνες σελίδας
Ηλεκτρ. έκδοση

justness of that magnificent conception of uniform design, which emboldened him to connect the physics of the Earth with the hitherto unexplored mysteries of the Heavens.

Instructive and interesting, however, as these physical speculations may be, it is still more pleasing to trace the uniformity of design which is displayed in the economy of sensitive beings; to compare the arts of human life with the instincts of the brutes, and the instincts of the different tribes of brutes with each other; and to remark, amidst the astonishing variety of means which are employed to accomplish the same ends, a certain analogy characterize them all; or to observe, in the minds of different individuals of our own species, the workings of the same affections and passions, manifesting, among men of every age and of every country, the kindred features of humanity. It is this which gives the great charm to what we call Nature in epic and dramatic composition,-when the poet speaks a language "to which every heart is an echo," and which, amidst the manifold effects of education and fashion, in modifying and disguising the principles of our constitution, reminds all the various classes of readers or of spectators, of the existence of those moral ties which unite them to each other, and to their common parent.*

Nor is it only in the material and moral worlds, when considered as separate and independent systems, that this unity of design is perceptible. They mutually bear to each other numberless relations, which are more particularly remarkable, when we consider both, in their combined tendencies with respect to human happiness and improvement. There is also a more general analogy, which these two grand departments of nature exhibit, in the laws by which their phenomena are regulated, and a consequent analogy between the methods of investigation peculiarly applicable to each. I have already repeatedly taken notice of the erroneous conclusions to which we are liable, when we reason directly from the one to the other; or substitute the fanciful analogies between them, which language occasionally suggests, as a philosophical explanation of the phenomena of either. But it does not follow from this, that there is no analogy between the rules of inquiry, according to which they are to be studied. On the contrary, is is from the principles of inductive philosophizing, which are applicable to both in common, that we infer the necessity of resting our conclusions in each, upon its own appropriate phenomena.

I shall only add, to what has been now stated on the head of analogy, that the numberless references and dependencies between the material and the moral worlds, exhibited within the narrow sphere of our observation on this globe, encourage and even authorize us to conclude, that they both form parts of one and the same plan ;—a conclusion congenial to the best and noblest principles of our nature, and which all the discoveries of genuine science unite in con

* Outlines of Moral Philosophy, pp. 198, 199. 3d edit.

firming. Nothing, indeed, could be more inconsistent with that irresistible disposition which prompts every philosophical inquirer to argue from the known to the unknown, than to suppose that, while all the different bodies which compose the material universe are manifestly related to each other, as parts of a connected whole, the moral events which happen on our planet are quite insulated; and that the rational beings who inhabit it, and for whom we may reasonably presume it was brought into existence, have no relation whatever to other intelligent and moral natures. The presumption unquestionably is, that there is one great moral system, corresponding to the material system; and that the connexions which we at present trace so distinctly among the sensible objects composing the one, are exhibited as so many intimations of some vast scheme, comprehending all the intelligent beings who compose the other. In this argument, as well as in numberless others which analogy suggests in favour of our future prospects, the evidence is precisely of the same sort with that, which first encouraged Newton to extend his physical speculations beyond the limits of the Earth. The sole difference is, that he had an opportunity of verifying the results of his conjectures by an appeal to sensible facts: but this accidental circumstance (although it certainly affords peculiar satisfaction and conviction to the astronomer's mind) does not affect the grounds on which the conjecture was originally formed, and only furnishes an experimental proof of the justness of the principles on which it proceeded. Were it not, however, for the palpable confirmation thus obtained of the Theory of Gravity, it would be difficult to vindicate against the charge of presumption, the mathematical accuracy, with which the Newtonians pretend to compute the motions, distances, and magnitudes of worlds, apparently so far removed beyond the examination of our faculties.*

"I know no author (says Dr. Reid) who has made a more just and a more happy use of analogical reasoning, than Bishop Butler, in his Analogy of Religion, Natural and Revealed, to the Constitution and Course of Nature. In that excellent work, the author does not ground any of the truths of religion upon Analogy, as their proper evidence. He only makes use of Analogy to answer objections against them. When objections are made against the truths of religion which may be made with equal strength against what we kuow to be true in the course of nature, such objections can have no weight." (Essays on the Intell. Powers, p. 54.)

To the same purpose it is observed by Dr. Campbell, that "analogical evidence is generally more successful in silencing objections than in evincing truth. Though it rarely refutes, it frequently repels refutation; like those weapons which, though they cannot kill the enemy, will ward his blows." (Phil. of Rhet. Vol. I. p. 145.)

This estimate of the force of analogical reasoning, considered as a weapon of controver sy, is discriminating and judicious The occasion on which the logician wields it to the best advantage is. undoubtedly, in repelling the objections of an adversary. But after the foregoing observations, I may be permitted to express my doubts, whether both of these ingenious writers have not somewhat underrated the importance of analogy as a medium of proof, and as a source of new information.-I acknowledge, at the same time, that between the positive and the negative applications of this species of evidence, there is an es sential difference. When employed to refute an objection, it may often furnish an argument irresistibly and unanswerably convincing: when employed as a medium of proof, it can never authorize more than a probable conjecture, inviting and encouraging farther examination. In some instances, however, the probability resulting from a concurrence of different analogies may rise so high, as to produce an effect on the belief scarcely distinguishable from moral certainty.



The foregoing observations have a close connexion with some reasonings hereafter to be offered in defence of the doctrine of final causes. They also throw additional light on what was remarked in a former chapter concerning the unity of truth;-a most important fact in the theory of the human mind, and a fact which must strike every candid inquirer with increasing evidence, in proportion to the progress which he makes in the interpretation of Nature. Hence the effect of philosophical habits in animating the curiosity, and in guiding the inventive powers; and hence the growing confidence which they inspire in the ever consistent and harmonious conclusions of inductive science. It is chiefly (as Bacon has observed) from partial and desultory researches that scepticism arises; not only as such researches suggest doubts which a more enlarged acquaintance with the universe would dispel, but as they withdraw the attention from those comprehensive views which combine into a symmetrical fabric -all whose parts mutually lend to each other support and stability -the most remote, and seemingly the most unconnected discoveries. "(1)Etenim symmetria scientiae, singulis scilicet partibus se invicem "sustinentibus, est, et esse debet, vera atque expedita ratio refellen"di objectiones minorum gentium: Contra, si singula axiomata, tan66 quam baculos fascis seorsim extrahas, facile erit ea infirmare, et 66 pro libito, aut flectere aut frangere. Num non in aula spatiosa "Consultius foret, unum accendere cereum, aut lychnuchum suspen"dere, variis luminibus instructum, quo omnia simul perlustrentur, 66 quam in singulos angulos quaquaversus exiguam circumferre lu"cernam ?""*


Use and Abuse of Hypotheses in Philosophical Inquiries.-Difference between Gratuitous Hypotheses, and those which are supported by presumptions suggested by AnalogyIndirect Evidence which a Hypothesis may derive from its agreement with the Phenomena.-Cautions against extending some of these conclusions to the Philosophy of the Human Mind.

As some of the reasonings in the former part of this Section may at first sight appear more favourabe to the use of Hypotheses, than is consistent with the severe rules of the Inductive Logic, it

* De Augment. Scient. Lib. i.

(1) [For the unity of science, as the various parts mutually sustain each other, is and ought to be the truest and most expeditious method of refuting the objections of puny sciolists. On the other hand, if you exhibit axioms drawn out singly like sticks from a faggot, it will be easy to lessen their force, and to bend or break them at pleasure. In a spacious apartment, would it not be advisable, to light a single wax candle, or to suspend a chandalier, set round with various lamps, by which all things may be seen at one view, rather than to carry round a single taper to separately examine every nook and corner ?]

may not be superfluous to guard against any such misapprehensions of my meaning, by subjoining a few miscellaneous remarks and illustrations.

The indiscriminate zeal against hypotheses, so generally avowed at present by the professed followers of Bacon, has been much encouraged by the strong and decided terms in which, on various occasions, they are reprobated by Newton.* But the language of this great man, when he happens to touch upon logical questions, must not always be too literally interpreted. It must be qualified and limited, so as to accord with the exemplifications which he himself has given of his general rules. Of the truth of this remark, the passages now alluded to afford a satisfactory proof; for, while they are expressed in the most unconditional and absolute terms, so many exceptions to them occur in his own writings, as to authorize the conclusion, that he expected his readers would of themselves be able to supply the obvious and necessary comments. It is probable that, in these passages, he had more particularly in his eye the Vortices of Des Cartes.

"The votaries of hypotheses (says Dr. Reid) have often been "challenged to shew one useful discovery in the works of nature "that was ever made in that way."† In reply to this challenge, it is sufficient on the present occasion to mention the theory of Gravitation, and the Copernican system. Of the former, we have the testimony of Dr. Pemberton, that it took its first rise from a conjecture or hypothesis suggested by analogy; nor, indeed, could it be considered in any other light, till that period in Newton's life, when, by a calculation founded on the accurate measurement of the earth by Picard, he evinced the coincidence between the law which regulates the fall of heavy bodies, and the power which retains the Moon in her orbit. The Copernican system, however, furnishes a case still stronger, and still more directly applicable to our purpose; in as much as the only evidence which the author was able to offer in its favour, was the advantage which it possessed over every other

*“Hypotheses non fingo. Quicquid enim ex phenomenis non deducitur hypothesis vocanda est, et hypotheses, seu metaphysicae, seu physicae, seu qualitatum occultarum, seu mechanicae, in philosophia experimentali locum non habent." See the general Scholium at the end of the Principia.

+ Essays on the Intellectual Powers of Man, p. 88, 4to edit. In another part of the same volume, the following assertion occurs. "Of all the discoveries that have been made concerning the inward structure of the human body, never one was made by conjecture. The same thing may be said, with justice, of every other part of the works of God, wherein any real discovery has been made. Such discoveries have always been made by patient observation, by accurate experiments, or by conclusions drawn by strict reasoning from observations and experiments; and such discoveries have always tended to refute, but not to confirm, the theories and hypotheses which ingenious mea had invented." Ibid. p. 49.

+ See note (R.)

[I do not fabricate hypotheses, whatever is not deduced from phenomena, may be called an hypothesis, and hypotheses whether metaphysical or physical, or of occult qualities, or mechanical, have no place in experimental philosophy.]

hypothesis, in explaining, with simplicity and beauty, all the phenomena of the heavens. In the mind of Copernicus, therefore, this system was nothing more than a hypothesis;-but it was a hypothesis conformable to the universal analogy of nature, always accomplishing her ends by the simplest means. "(1) C'est pour la "simplicite (says Bailly) que Copernic replaça le soleil au centre "du monde ; c'est pour elle que Kepler va détruire tous les épi"cycles que Copernic avoit laissés subsister: peu de principes, "de grands moyens en petit nombre, des phénomènes infinis et "variés, voilà le tableau de l'univers."*

Histoire de l'Astronomie Moderne, Tome II. p. 2.

From this anticipation of simplicity in the laws of nature (a logical principle not less universally recognized among ancient than among modern philosophers.) Bailly has drawn an argument in support of his favourite hypothesis concerning the origin of the sciences. His words are these: "La simplicité n'est pas essentiellement un principe, un axiôme, c'est le résultat des travaux ; ce n'est pas une idée de l'enfance du monde, elle appartient à la maturité des hommes; c'est la plus grande des vérités que l'observation constante arrache à l'illusion des effets: ce ne peut être qu'un reste de la science primi. tive. Lorsque chez un peuple, possesseur d'une mythologie compliquée, et qui n'a d'autre physique que ces fables, les philosophes, voulant réduire la nature à un seul principe, an nonceront que l'eau est la source de toutes choses, ou le feu l'agent universel, nous dirons à ces philosophies: vous parlez une langue que n'est pas la vôtre; vous avez saisi par un ins inct philosophique ces vé ités au-dessus de votre siècle, de votre nation, et de vousmêmes; c'est la sagesse des anciens qui vous a été transmise par tradition."—&c. &c. &c. -Ibid. p. 4.

To the general remark which introduces this passage I readily subscribe. The confi dence with which philosophers anticipate the simplicity of Nature's laws is unquestiona bly the result of experience, and of experience alone; and implies a far more extensive knowledge of her operations than can be expected from the uninformed multitude. The inference however, deduced from this, by the ingenious and eloquent, but sometimes too fanciful historian, is not a little precipitate. The passion for excessive simplification, so remarkably exemplified in the physical systems of the Greeks, seems to be sufficiently accounted for by their scanty stock of facts, combined with that ambition to explain every thing from the smallest possible number of data, which, in all ages of the world, has been one of the most common infirmities of genius. On the other hand, the principle in question, when stated in the form of a proposition, is of so abstract and metaphysical a na ture, that it is highly improbable it should have survived the shock of revolutions which had proved fatal to the memory of particular discoveries. The arts, it has been frequently observed, are more easily transmitted by mere tradition, from one generation to anoth⚫ er, than the speculative sciences; and, for a similar reason, physical systems are far less likely to sink into oblivion than abstract maxims, which have no immediate reference to objects of sense, or to the ordinary concerns of life.

+[Simplicity is not essentially a principle, an axiom; it is the result of study. It is not an idea belonging to the infancy of the world, but rather to the maturity of man. It is the greatest of truths which constant observation rescues from the confusion of a multitude of facts. It cannot but be a remnant of primitive science. When amongst a people, possessed of a complicated mythology, and who have no other philosophy than fables, the philosophers, desirous of reducing nature to one single principle, shall announce that water is the source of all things, or fire the universal agent, we shall say to hese philosophers, you speak a language which is not your own; you have seized by a philosophic instinct these truths so far above your age, your nation, and yourselves; it is the wisdom of the ancients which has been transmitted to you by tradition, &c.]

(1) It was on account of the simplicity of the system, that Copernicus replaced the sun in the centre of the world. On this account Kepler proceeded to destroy the epicycles which Copernicus had permitted to remain. With few principles, with great means, but of a very limited number, with phenomena infinite and various; behold the picture of the uni verse !]

« ΠροηγούμενηΣυνέχεια »