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it. And, 3. That there are some indisputable facts which favour the opposite hypothesis. In proof of the last proposition, among a variety of other arguments, an appeal has been made to the compressibility and elasticity of all known bodies; to their contraction by cold ; and to certain optical and electrical experiments, which shew that various ef. fects, which our imperfect senses lead us to ascribe to the actual contact of different bodies, are, in fact, produced by a repulsive power, extending to a real, though imperceptible distance from their surfaces. The same phenomena, therefore, may be produced by repulsion, which we commonly ascribe to contact; and if so, why not refer to the same cause all effects of the same nature ?”
* The following passage in Locke, when considered in conanection with some others in his writings, would almost tempt one to think, that a theory concerning Matter, somewhat analogous to that of Boscovich, had occasionally passed through his mind. —“Nay, possibly, if we could emancipate ourselves from vulgar “notions, and raise our thoughts as far as they could reach, to “a closer contemplation of things, we might be able to aim at “some dim and seeming conception, how matter might at first “ be made, and begin to exist by the power of that eternal first “Being.—But this being what would perhaps lead us too far “from the notions on which the philosophy now in the world “is built, it would not be pardonable to deviate so far from them “as to inquire, so far as grammar itself would authorize, if the “common settled opinion opposes it.”—Essay on Human Understanding, Book iv. chap. x. § 18.
Whoever chooses to examine the grounds upon which I have hazarded the foregoing observation, may compare the passage just quoted with what Locke has said of cohesion, in Book ii. chap. xxiii. § 23, 24, et seq. more particularly in § 26 and 27.
From the same passage, Dr Reid conjectures, that “Locke
A theory, essentially the same with this, has been proposed of late by different writers in this island, who seem to have been led to it entirely by their own speculations, without any knowledge of its having been previously started by another; and it has been in consequence of the particular view which some of them have taken of the subject, that the misapprehension which I am anxious at present to correct has chiefly arisen. In fact, the systems of Boscovich, and of Berkeley, have not the most remote relation to each other. The account, indeed, of some of the qualities of Matter which is given in the former, is very different from that commonly entertained; but this account does not call in question the reality of Matter, as an existence distinct from the perceiving Mind. It does not affect, in the least, our notions of extension and figure ; nor even those of hardness and softness, any further than as
“had a glimpse of the system which Berkeley afterwards ad“vanced, though he thought proper to suppress it within his own “breast.” (Essays on the Intell. Powers, p. 170.) I think it much more probable, from the hints dropped in other parts of his essay, that he had some vague notion of a theory approaching to that of Boscovich. The following remark confirms me in this conjecture: “Hardness consists in a firm cohesion of the parts of matter, “making up masses of a sensible bulk, so that the whole does “net easily change its figure. And, indeed, hard and soft are “names that we give to things only in relation to the constitu“tion of our own bodies; that being generally called hard by us, “which will put us to pain sooner than change figure by the “pressure of any part of our bodies; and that, on the contrary, “soft, which changes the situation of its parts upon an easy and “unpainful touch.” Book ii. chap. iv. § 4.—See Note (I.)
it defines these qualities by the relation which they bear to our animal force. The resistance opposed to our efforts implies an existence distinct from ours, as much as the efforts we are conscious of making imply our own existence; and, therefore, whether we proceed on the common notions concerning matter, or on the hypothesis of Boscovich, the authority of that law of our nature which leads us to ascribe to things external an independent and permanent existence, remains unshaken. According to Berkeley, extension and figure, hardness and softness, and all other sensible qualities, are mere ideas of the mind, which cannot possibly exist in an insentient substance. * That the inference which I have now drawn against the scheme of idealism, from the theory of Boscovich, is perfectly agreeable to the metaphysical views of that profound and original philosopher, appears from various passages in his works : in particular, from the following observations, which I translate literally from one of his supplements to the didactic poem of Benedictus Stay, de Systemate Mundi : “By the power of reflection, we are enabled to
* A remark to the same purpose has been made by Mr Smith, in his Essay on the External Senses. “Whatever system may “be adopted concerning the hardness or softness, the fluidity or “solidity, the compressibility or incompressibility of the resist“ing substance, the certainty of our distinct sense, and feeling of “its externality, or of its entire independency upon the organ “which perceives it, or by which we perceive it, cannot, in the “smallest degree, be affected by any such system."—Essays on Philosophical Subjects, p. 204.
“distinguish two different classes of ideas excited “in our minds. To some of these we are impelled, “ by a very powerful instinct, common to all men, “to ascribe an origin foreign to the mind itself, and “depending on certain external objects. Others “we believe, with the most complete conviction, to “ have their origin in the mind, and to depend on “the mind for their existence. The instruments “ or organs by which we receive the first kind of “ideas are called the senses : their external cause, “or, as it is commonly called, the object, is denoted “by the words matter and body. The source of “the second class of our ideas (which we discover “by reflecting on the subjects of our own conscious“mess) is called the mind or soul. “In this manner we become acquainted with two “different kinds of substances (the only substances “of which we possess any knowledge); the one, a “sensible or perceptible substance; the other, a sub“stance endowed with the powers of thought and “of volition. Of the existence of neither is it possi“ble for us to doubt (such is the force of those inti“mations we receive from nature); not even in those “cases when, offering violence to ourselves, we lis“ten to the suggestions of the Pyrrhonists and the “Egoists, and other sophistical perverters of the “truth. Nay, even these sceptics themselves are “forced to acknowledge, that whatever doubts they “may have experienced in their hours of specula“tion, vanish completely when the objects of their “doubts are presented to their senses.” “
* Roma, 1755, Tom. i. p. 331.
I do not take upon me to defend the propriety of all the expressions employed in the foregoing passage. I quote it merely as a proof, that Boscovich himself did not conceive that his peculiar notions concerning the nature of Matter had the slightest tendency to favour the conclusions of Berkeley. On the contrary, he states his dissent from these conclusions in the strongest and most decided terms; coinciding so exactly with Reid in the very phraseology he uses, as to afford a presumption, that it approaches nearly to a correct and simple enunciation of the truth.
In the foregoing remarks on Boscovich's theory, considered in contrast with that of Berkeley, I have had an eye chiefly to some speculations of the late Dr Hutton; a philosopher eminently distinguished by originality of thought; and whose writings could not have failed to attract much more notice than they have yet done, if the great variety of his scientific pursuits had left him a little more leisure to cultivate the arts of composition and of arrangement. It would be fortunate, in this respect, for his literary fame, if the same friendly and skilful hand which has illustrated and adorned his geological researches, would undertake the task of guiding us through the puzzling, but interesting labyrinth of his metaphysical discussions.
The following is the conclusion of Dr Hutton's argument concerning hardness and incompressibility:
“In thus distinguishing things, it will appear,