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or at least does not rest the point in dispute upon its right foundation. If there were no first principles (it has been said) or, in other words, if a reason could be given for every thing, no process of deduction could possibly be brought to a conclusion. The remark is indisputably true; but it only proves (what no logician of the present times will venture to deny) that the mathematician could not demonstrate a single theorem, unless he where first allowed to lay down his definitions; nor the natural philosopher explain or account for a single phenomenon, unless he were allowed to assume, as acknowledged facts, certain general laws of nature. What inference does this afford in favour of that particular class of truths to which the preceding observations relate, and against which the ingenuity of modern sceptics has been more particularly directed? If I be not deceived, these truths are still more intimately connected with the operations of the reasoning faculty than has been generally imagined; not as the principles (apxa) from which our reasonings set out, and on which they ultimately depend; but as the necessary conditions on which every step of the deduction tacitly proceeds; or rather, (if I may use the expression) as essential elements which enter into the composition of reason itself.

2. In this last remark I have anticipated, in some measure, what I had to state with respect to the second coincidence alluded to, between mathematical axioms, and the other propositions which I have comprehended under the general title of fundamental laws of human belief. As the truth of axioms is virtually presupposed or implied in the successive steps of every demonstration, so, in every 2 analogy between

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step of our reasonings concerning the order of Nature, we proceed on the supposition, that the laws by which it is regulated will continue uniform as in time past; and that the material universe math: axihas an existence independent of our perceptions. I need scarcely add, that, in all our reasonings whatever, whether they relate to necessary or to contingent truths, our own personal identity and many lany the evidence of memory are virtually taken for granted. These of being different truths all agree in this, that they are essentially involved in the exercise of our rational powers; although, in themselves, they furnish no principles or data by which the sphere of our knowledge can, by any ingenuity, be enlarged. They agree farther in being tacitly acknowledged by all men, learned or ignorant, without any formal enunciation in words, or even any con

"But there are some who, through ignorance, make an attempt to prove even this principle, (that it is impossible for the same thing to be and not to be.) For it is a mark of ignorance, not to be able to distinguish those things which ought to be demonstrated from things of which no demonstration should be attempted. In truth, it is altogether impossible that every thing should be susceptible of deinonstration; otherwise the pro cess would extend to infinity, and, after all our labour, nothing would be gained.” ́ In the sentence immediately preceding this quotation, Aristotle calls the maxim in ques tion, fibran Tav apxav Taσan, "the most certain of all principles."

To the same purpose, Dr. Reid has said: "I hold it to be certain, and even demonstrable, that all knowledge got by reasoning must be built on first principles. This (he adds) is as certain as that every house must have a foundation."-Essays on Int. Powers, p. 558, 4to edit.

scious exercise or reflection. It is only at that period of our intellectual progress when scientific arrangements and metaphysical refinements begin to be introduced, that they become objects of attention to the mind, and assume the form of propositions.

In consequence of these two analogies or coincidences, I should Why not have been inclined to comprehend, under the general title of axioms, include both all the truths which have been hitherto under our review, if the common usage of our language had not, in a great measure, approclases opriated that appellation to the axioms of mathematics; and if the muths unda view of the subject which I have taken, did not render it necessary for me, to direct the attention of my readers to the wide diversity between the branches of knowledge to which they are respectively


the of axioms subservient.

I was anxious also to prevent these truths from being all identified, in point of logical importance, under the same name. The fact is, that the one class, (in consequence of the relation in which they stand to the demonstrative conclusions of geometry,) are comparatively of so little moment, that the formal enumeration of them was a matter of choice rather than of necessity; whereas the other class have unfortunately been raised, by the sceptical controversies of modern times, to a conspicuous rank in the philosophy of the human mind. I have thought it more advisable, therefore, to bestow on the latter an appropriate title of their own; without however going so far, as to reject altogether the phraseology of those who have annexed to the word axiom a more enlarged meaning than that which I have usually given to it. Little inconvenience, indeed, can arise from this latitude in the use of the term; provided only it be always confined to those ultimate laws of belief, which, although they form the first elements of human reason, cannot with propriety be ranked among the principles from which any of our scientific conclusions are deduced.

Corresponding to the extension which some late writers have Intiution given to axioms, is that of the province which they have assigned to intuition; a term which has been applied, by Dr. Beattie and how used others, not only to the power by which we perceive the truth of the axioms of geometry, but to that by which we recognize the authority of the fundamental laws of belief, when we hear them enunciated in language. My only objection to this use of the word w is, that it is a departure from common practice; according to which, wt. if I be not mistaken, the proper objects of intuition are propositions analogous to the axioms prefixed to Euclid's Elements. In some other respects, this innovation might perhaps be regarded as an improvement on the very limited and imperfect vocabulary of which we are able to avail ourselves in our present discussions.*


According to Locke, we have the knowledge of our own existence by intuition; of the existence of God by demonstration; and of other things by sensation. Book iv. Chap. 9. § 2.

This use of the word intuition seems to be somewhat arbitrary. The reality of our own existence is a truth which bears as little analogy to the axions of mathematics, as any



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To the class of truths which I have here called laws of belief, or elements of reason the title of principles of common sense was long ago given by Father Buffier, whose language and doctrine concern- of common ing them bears a very striking resemblance to thotrine concern our later Scottish logicians. This, at least, strikes me as the meaning which these writers in general annex to the phrase; although all of them have frequently employed it with a far greater degree Myution of latitude. When thus limited in its acceptation, it is obviously liable, in point of scientific accuracy, to two very strong objections, both of which have been already sufficiently illustrated. The first is, that it applies the appellation of principles to laws of belief from which no inference can be deduced; the second, that it refers the origin of these laws to common sense.*-Nor is this phraseology more agreeable to popular use than to logical precision. If we were to suppose an individual, whose conduct betrayed a disbelief of his own existence, or of his own identity, or of the reality of surrounding objects, it would by no means amount to an adequate description of his condition to say, that he was destitute of common sense. We should at once pronounce him to be destitute of reason, and would no longer consider him as a fit subject of discipline or of punishment. The former expression, indeed, would only imply that he was apt to fall into absurdities and improprieties in the common concerns of life. To denominate, therefore, such laws of belief as we have now been considering, constituent elements of human reason, while it seems quite unexceptionable in point of technical distinctness, cannot be justly censured as the slightest deviation from our habitual forms of speech. On the same grounds, it may be fairly questioned, whether the word reason would not, on some Reason occasions, be the best substitute which our language affords for intuition, in that enlarged acceptation which has been given to it of Intuition. for late. If not quite so definite and precise as might be wished, it would be at least employed in one of those significations in which it is already familiar to every ear; whereas the meaning of intuition, when used for the same purpose, is stretched very far beyond its ordinary limits. And in cases of this sort, where we have to choose between two terms, neither of which is altogether unexceptionable, it will be found much safer to trust to the context for restricting, in the reader's mind, what is too general, than for enlarging what use has accustomed us to interpret in a sense too narrow.

other primary truth whatever. If the province of intuition, therefore, be extended as far as it has been carried by Locke in the foregoing sentence, it will not be easy to give a good reason why it should not be enlarged a little farther. The words intuition and demonstration, it must not be forgotten, have, both of them, an etymological reference to the sense of seeing; and when we wish to express, in the strongest terms, the most com. plete evidence which can be set before the mind, we compare it to the light of noon-day; -in other words, we compare it to what Mr. Locke here attempts to degrade, by calling it the evidence of sensation.

* See the preceding part of this section, with respect to the word principle; and the Account of Reid's Life, for some remarks on the proper meaning of the phrase common sense.


I must add, too, in opposition to the high authorities of Dr. Johnson and Dr. Beattie,* that, for many years past, reason has been very seldom used by philosophical writers, or indeed by correct writers of any description, as synonymous with the power of reasoning. To appeal to the light of human reason from the reasonings of the schools, is surely an expression to which no good objection can be made, on the score either of vagueness or of novelty. Nor has the etymological affinity between these two words the slightest tendency to throw any obscurity on the foregoing expression. On the contrary, this affinity may be of use in some of our future arguments, by keeping constantly in view the close and inseparable connexion, which will be afterwards shown to exist between the two different intellectual operations which are thus brought into immediate contrast.

The remarks which I have stated in the two preceding sections, comprehend every thing of essential importance which I have to offer on this article of logic. But the space which it has occupied for nearly half a century, in some of the most noted philosophical works which have appeared in Scotland, lays me under the necessity, before entering on a new topic, of introducing, in this place, a few critical scrictures on the doctrines of my predecessors.


Continuation of the Subject.-Critical Remarks on some late Controversies to which it bas given rise. Of the Appeals which Dr. Reid and some other Modern Writers have made, in their Philosophical Discussions to Common Sense, as a Criterion of Truth.

I OBSERVED, in a former part of this work, that Dr. Reid acknow

Or Kid ledges the Berkeleian system to be a logical consequence of the

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opinions universally admitted by the learned at the time when Berkeley wrote. In the earlier part of his own life, accordingly, he informs us, that he was actually a convert to the scheme of Berkelian immaterialism; a scheme which he probably considered as of a perfectly inoffensive tendency, as long as he conceived the existence of the material world to be the only point in dispute. Finding, however, from Mr. Hume's writings, that, along with this paradox, the ideal theory necessarily involved various other consequences of a very different nature, he was led to a careful examination of the data on which it rested; when he had the satisfaction to discover

* Dr. Johnson's definition of Reason was before quoted. The following is that given by Dr. Beattie :

Reason is used by those who are most accurate in distinguishing, to signify that power of the human mind by which we draw inferences, or by which we are convinced, that a relation belongs to two ideas, on account of our having found that these ideas bear certain relations to other ideas. In a word, it is that faculty which enables us, from relations or ideas that are known, to investigate such as are unknown, and without which we never could proceed in the discovery of truth a single step beyond first principles or intui. tive axioms."-Essay on Truth, Part 1. Chap. i.

that its only foundation was a hypothesis, unsupported by any evidence whatever but the authority of the schools.*

From this important concession of a most impartial and competent judge, it may be assumed as a fact, that, till the refutation of the ideal theory in his own " Inquiry into the Human Mind," the partisans of Berkeley's system remained complete masters of the controversial field; and yet, during the long period which intervened, it is well known how little impression that system made on the belief of our soundest philosophers. Many answers to it were attempted, in the mean time, by various authors, both in this country and on the continent; and by one or other of these, the generality of the learned professed themselves to be convinced of its futility;— the evidence of the conclusion (as in many other cases) supporting the premises, and not the premises the conclusion.f A very curious anecdote, in illustration of this, is mentioned in the life of Dr. Berkeley. After the publication of his book, it appears that he had an interview with Dr. Clarke; in the course of which, Clarke (it is said) discovered a manifest unwillingness to enter into the discussion, and was accused by Berkeley of a want of candour.-The story (which, if I recollect right, rests on the authority of Whiston) has every appearance of authenticity; for as Clarke, in common with his antagonist, regarded the principles of the ideal theory as incontrovertible, it was perfectly impossible for him, with all his acuteness, to detect the flaw to which Berkeley's paradox owed its plausibility. In such circumstances, would it have been unphilosophical in Clarke to have defended himself, by saying: "Your conclusion "not only contradicts those perceptions of my senses, the evidence

It was not, therefore, (as has very generally been imagined by the followers of Berke. ley) from any apprehension of danger in his argument against the existence of matter, that Reid was induced to call in question the ideal theory: but because he thought that Mr. Home had clearly shown, by turning Berkeley's weapons against himself, that this theory was equally subversive of the existence of mind. The ultimate object of Berkeley and of Reid was precisely the same; the one asserting the existence of matter from the very same motive which led the other to deny it.

When I speak of Reid's asserting the existence of matter, I do not allude to any new proofs which he has produced of the fact. This he rests on the evidence of sense, as he rests the existence of the mind on the evidence of consciousness. All that he professes to have done is, to show the inconclusiveness of Berkeley's argument against the former, and that of Hume against the latter, by refuting the ideal hypothesis, which is the common foundation of both.

+ The impotent, though ingenious attempt of Berkeley (not many years after the date of his metaphysical publications) to shake the foundations of the newly invented method of Fluxions, created, in the public mind, a strong prejudice against him, as a sophistical and paradoxical disputant; and operated as a more powerful antidote to the scheme of immaterialism, than all the reasonings which his contemporaries were able to oppose to it. This unfavourable impression was afterwards not a little confirmed, by the ridicule which he incurred in consequence of his pamphlet on the Virtues of Tar-water; a performance, however, of which it is but justice to add, that it contains a great deal more, both of sound philosophy and of choice learning, than could have been expected from the subject.

Philosophical Essays, Note E.

That Clarke would look upon the Berkeleian theory with more than common feelings of suspicion and alarm, may be easily conceived, when it is recollected that, by denying the independent existence both of space and of time, it put an end at once to his celebrated ar gument a priori, for the existence of God.

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