have added;

"The conclusion which it involves is a demonstration in the form of a reductio ad absurdum, of the soundness of the ideal theory, on which the whole of your argument is built ?"*

I am far from supposing that Berkeley would have adnitted this consideration as decisive of the point in dispute. On the contrary, it appears from his writings, that the scheme of immaterialism was, in his opinion, more agreeable to popular belief, than the received theories of philosophers concerning the independent existence of the external world; nay, that he considered it as one of the many advantages likely to result from the universal adoption of his system, that men would thereby be reduced from paradoxes to common sense.”

I acknowledge, very readily, that the force of this indirect mode of reasoning is essentially different in mathematics, from what it is in the branches of knowledge; for the objects of mathematics (as will afterwards more fully appear) not being truth, but systematical connexion and consistency, whenever two contradictory propositions occur, embracing evidently the only possible suppositions on the point in question, if the one can be shown to be incompatible with the definitions or hypotheses on which the science is founded, this may be regarded as perfectly equivalent to a direct proof of the legitimacy of the opposite conclusion. In the other sciences, the force of a reductio ad absurdum depends entirely on the maxim, "That truth is always consistent with itself;" a maxim which, however certain, rests evidently on grounds of a more abstract and metaphysical nature than the indirect demonstrations of geometry. It is a maxim, at the same time, to which the most sceptical writers have not been able to refuse their testimony. "Truth (says Mr. Hume himself) is one thing, but errors are numberless, and every man has a different one."

The unity, or systematical consistency of truth, is a subject which well deserves to be farther prosecuted. It involves many important consequen ces, of which Mr. Hume does not, from the general spirit of his philosophy, seem to have been sufficiently aware.

The question, however, if not decided by this discussion, would at least have been brought to a short and simple issue; for the paramount authority of the common sense or common reason of mankind being equally recognized by both parties, all that remained for their examination was, whether the belief of existence, or that the non-existence of matter, was sanctioned by this supreme tribunal? For ascertaining this point, nothing more was necessary, than an accurate analysis of the meaning annexed to the word existence which analysis would have at once shown, not only that we are irresistibly led to ascribe to the material world all the independent reality which this word expresses, but that it is from the material world that our first and most satisfactory notions of existence are drawn. The mathematical affections of matter (extension and figure) to which the constitution of the mind imperiously forces us to ascribe an existence, not only independent of our perceptions, but necessary and eternal, might more particularly have been pressed upon Berkeley, as proofs how incompatible his notions were with those laws of belief, to which the learned and the unlearned must in common submit.*

But farther, (in order to prevent any cavil about the foregoing illustration,) we shall suppose that Clarke had anticipated Hume in perceiving that the ideal theory went to the annihilation of mind as well as of matter; and that he had succeeded in proving, to the satisfaction of Berke ley, that nothing existed in the universe but impressions and ideas. Is it possible to imagine, that Berkeley would not immediately have seen and acknowledged, that a theory which led to a conclusion directly contradicted by the

* See Note (B.)

evidence of consciousness, ought not, out of respect to ancient authority, to be rashly admitted; and that, in the present instance, it was much more philosophical to argue from the conclusion against the hypothesis, than to argue from the hypothesis in proof of the conclusion? No middle course, it is evident, was left him between such an acknowledgment, and an unqualified acquiescence in those very doctrines which it was the great aim of his system to tear up by the roots.

The two chief objections which I have heard urged against this mode of defence, are not perfectly consistent with each other. The one represents it as a presumptuous and dangerous innovation in the established rules of philosophical controversy, calculated to stifle entirely a spirit of liberal inquiry: while the other charges its authors with all the meanness and guilt of literary plagiarism. I shall offer a few slight remarks upon each of these accu

sations.

1. That the doctrine in question is not a new one, nor even the language in which it has been recently stated an innovation in the received phraseology of logical science, has been shown by Dr. Reid, in a collection of very interesting quotations, which may be found in different parts of his Essays on the Intellectual Powers of Man, more particularly in the second chapter of the sixth essay. Nor has this doctrine been generally rejected even by those writers who, in their theories, have departed the farthest from the ordinary opinions of the world. Berkeley has sanctioned it in the most explicit manner, in a passage already quoted from his works, in which he not only attempts the extraordinary task of reconciling the scheme of

immaterialism with the common sense of mankind, but alleges the very circumstance of its conformity to the unsophisticated judgment of the human race, as a strong argument in its favour, when contrasted with the paradoxical doctrine of the independent existence of matter. The ablest advocates, too, for the necessity of human actions, have held a similar language; exerting their ingenuity to show, that there is nothing in this tenet which does not perfectly accord with our internal consciousness, when our supposed feelings of liberty, with all their concomitant circumstances, are accurately analyzed, and duly weighed.* In this respect, Mr. Hume forms almost a solitary exception, avowing, with the greatest frankness, the complete repugnance between his philosophy and the laws of belief to which all men are subjected by the constitution of their nature. "I dine; I play a game at backgammon; I converse, and am happy with my friends; and when, after three or four hours of amusement, I would return to these speculations, they appear so cold, so strained, and so ridiculous, that I cannot find in my heart to enter into them any further. Here, then, I find myself absolutely and necessarily determined to live, and talk, and act, like other people, in the common affairs of life."+

* This, I own, appears to me the only argument for the scheme of neces sity, which deserves a moment's consideration, in the present state of the controversy: and it is certainly possible to state it in such a form as to give it some degree of plausibility to a superficial inquirer. On this point, however, as on many others, our first and third thoughts will be found perfectly to coincide; a more careful and profound examination of the question infallibly bringing back to their natural impressions, those who reflect on the subject with candour and with due attention. Having alluded to so very important a controversy, I could not help throwing out this hint here. The farther prosecution of it would be altogether foreign to my present purpose. + Treatise of Human Nature, Vol. I. p. 467.

Even Mr. Hume himself, however, seems at times, to forget his sceptical theories, and sanctions, by his own authority, not only the same logical maxims, but the same mode of expressing them, which has been so severely censured in some of his opponents. "Those (he observes) who have refused the reality of moral distinctions, may be ranked among the disingenuous disputants. The only way of converting an antagonist of this kind, is, to leave him to himself; for, finding that nobody keeps up the controversy with him, 'tis probable he will at last, of himself, from mere weariness, come over to the side of common sense and reason."*

To the authorities which have been already produced by Reid and his successors, in vindication of that mode of arguing which is now under our review, I shall beg leave to add another, which, as far as I know, has not yet been remarked by any of them; and which, while it effectually removes from it the imputation of novelty, states, in clear and forcible terms, the grounds of that respect to which it is entitled, even in those cases where it is opposed by logical subtleties which seem to baffle all our powers of reasoning.

"What is it (said some of the ancient sophists) which constitutes what we call little, much, long, broad, small, or great? Do three grains of corn make a heap? The answer must be-No. Do four grains make a heap? You must make the same answer as before.-They continued their interrogations from one grain to another, without end; and if you should happen at last to answer,

* Inquiry concerning the Principles of Morals.