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of wisdom derived from the intercourses of life, of husbandry, of moral duty, of peace and war, are all drawn from this source, as well as the finest speculations of science. Aristotle, therefore, in his physical and metaphysical works, did nothing more by making a continued appeal to nature, than had been done from the most remote periods by all who undertook, from considering the principles of human nature to deduce any of the maxims of truth and duty, or explain any of the appearances of the earth and heavens. This, however, is a very different thing from conceiving the sublime idea, that in order to arrive at a true theory of nature, or establish a just philosophy, instead of relying upon our own resources and ingenuity, we must direct our inquiries to her alone, and from her responses imbibe all our lessons of instruction. There is a wide and most essential distinction between directing the attention of the mind to the formation of a system, and occasionally appealing to nature only to confirm it, and directing our attention only to the collection of phenomena, on which alone to ground our conclusions. In the one case, we shall inevitably be led to spin subtil and ingenious theories out of our own brains, and then constrain all appearances to become tributary to them; in the other, we shall bend our own opinions to facts. The one mode of procedure, has led to the adoption of numberless hypotheses that have successively appeared upon the stage of human life, and then perished before the force of subsequent inquiry, the other since the time of Bacon, has been leading to the most important and interesting discoveries.
Thus we have endeavoured, as far as we are able, to explain what is implied in the inductive method of investigation. It implies the exercise of reason, ascending to and establishing the great principles of science from an observation of the appearances of nature, and inferring the causes of things from a rigorous examination of effects. The only way in which an argument of this kind can be invalidated, is by
the exhibition of contradictory instances or facts; and in this case, we must always limit our conclusions according to the number and force of these instances or facts.
Upon a review of the whole subject, it will appear, that all those branches of science must rest upon induction, in which the object of pursuit is, the investigation of either moral or physical nature. Natural and moral philosophy, chymistry, medicine, rhetoric, as far as the rules which it prescribes are founded in the principles of human nature, political science, in which case the statesman finds the whole history of man unfolding to him its ample page, and com. prising an interesting series of moral experiments from which his lessons may be educed; all these are dependent for their sublimest maxims of truth and expediency upon the inductive method of investigation. Not a single step can be taken or attainment made in any of these branches of science, without the aid of this powerful instrument. And when we reflect upon the future probable progress of philosophy, and consequent extension of the dominion of man over nature, from the influence of this wonder-working engine, if skilfully and sedulously employed, the mind is filled with the most sublime anticipations. Upon this method of procedure, there are no limits to be set to the advances which may be made by continued accumulations to the stock of human knowledge. Here we attain, in truth and sincerity, to what was only assumed for purposes of deception and imposture, the days of pagan ignorance and superstition, the art of vaticination. Induction, is the pillar of cloud that shall conduct us by a slow but sure progress, through many a devious track, indeed, and arduous ascent in the wilderness of nature, until at length we reach those exalted heights from which, like Moses upon the top of Pisgah, we may catch a view of the promised land of truth and knowledge, where the deepest mysteries shall be revealed to us, and in a kind of philosophic vision, from a contemplation of the past and
present, be able to predict the future. It is a voyage of discovery, a project of circumnavigating the whole globe of nature in quest of materials, out of which to construct the solid fabric of learning. It is the commencement of a campaign, furnished with armour that renders us invincible, where victory after victory may be obtained, and conquest after conquest achieved. In a word, induction, is the great vehicle by which in all the branches of modern science, such wonders have been accomplished. It was by the masterly use of this instrument, that Newton unfolded to the astonishment of mankind, the awful and hitherto impenetrable mysteries of the physical world; while Locke successfully pursued his way through those dark and shady paths in the dominions of the moral, which appeared impervious to the view and inaccessible to the footsteps of men; and, in fine, that all the modern investigators of nature, have so triumphantly extended their researches into her most hidden and remote departments.
Reasoning from Analogy.
CONNECTED with the system of induction, as a mean of acquiring information, though not amounting to so high a degree of proof or to as strong probability, is that of analogical reasoning. This too is a mode of arriving at conclusions to which we give assent, and in which our understand. ings repose confidence, of very early origin in the progress of human improvement. As soon as the philosopher or primitive man, whom we have before introduced upon the stage engaged in the pursuit of knowledge, began to collect the lessons of experience, he would naturally endeavour to extend his maxims beyond his own experience and observation, and make them comprehend cases that were similar. From the circumstance that the fruit which he found upon the tree, was wholesome in its operation upon his body and those of his immediate companions, he would conclude that it would be so to all other human beings like himself; if he found a few animals or plants, of a species innocent or noxious, he would extend the same properties to others that resembled them. This is reasoning from analogy. And if it be thought from the consideration, that when we have seen any cause produce a particular effect, whenever we see the same cause afterwards, we are prone to expect the same effect to accompany it, that there is need of the supposition of an inductive principle in our nature: from our proceeding so immediately to reasoning from analogy, there ought to be also an analogical one. There is no need, however, of the