though in effect coinciding, is considered under a different aspect; when what is single in the subject is divided in the predicate, and conversely; or when what is a whole in the one is regarded as a part of something else in the other; such propositions lead to the discovery of innumerable and apparently remote relations. One added to four may be accounted no other than a definition of the word five, as was remarked above. But when I say, "Two added to three are equal to five," I advance a truth, which, though equally clear, is quite distinct from the preceding. Thus, if one should affirm, "Twice fifteen make thirty," and again, "Thirteen added to seventeen make thirty," nobody would pretend that he had repeated the same proposition in other words. The cases are entirely similar. In both, the same thing is predicated of ideas which, taken severally, are different. From these again result other equations, as, "One added to four are equal to two added to three," and "twice fifteen are equal to thirteen added to seventeen." Now it is by the aid of such simple and elementary principles, that the arithmetician and the alegebraist proceed to the most astonishing discoveries. Nor are the operations of the geometrician essentially different. By a very few steps you are made to perceive the equality, or rather the coincidence, of the sum of the two angles formed by one straight line falling on another, with two right angles. By a process equally plain you are brought to discover, first, that if one side of a triangle be produced, the external angle will be equal to both the internal and opposite angles, and then, that all the angles of a triangle are equal to two right angles. So much for the nature and use of the first kind of intuitive evidence, resulting from pure intellection.

PART II.-Consciousness.

The next kind is that which ariseth from consciousness. Hence every man derives the perfect assurance that he hath of his own existence. Nor is he only in this way assured that he exists, but that he thinks, that he feels, that he sees, that he hears, and the like. Hence his absolute certainty in regard to the reality of his sensations and passions, and of every thing whose essence consists in being perceived. Nor does this kind of intuition regard only the truth of the original feelings or impressions, but also many of the judgments that are formed by the mind, on comparing these one with another. Thus the judgments we daily and hourly form, concerning resemblances or disparities in visible objects, or size in things tangible, where the odds is considerable, darker or lighter tints in colours, stronger or weaker tastes or smells, are all self-evident, and discoverable at once. It is from the same principle that, in regard to ourselves, we judge infallibly concerning the feelings,

whether pleasant or painful, which we derive from what are called the internal senses, and pronounce concerning beauty or deformity, harmony or discord, the elegant or the ridiculous. The difference between this kind of intuition and the former will appear on the slightest reflection. The former concerns only abstract notions and ideas, particularly in regard to number and extension, the objects purely of the understanding; the latter concerns only the existence of the mind itself, and its actual feelings, impressions or affections, pleasures or pains, the immediate subjects of sense, taking that word in the largest acceptation. The former gives rise to those universal truths, first principles or axioms, which serve as the foundation of abstract science; whereas the latter, though absolutely essential to the individual, yet as it only regards particular preceptions, which represent no distinct genus or species of objects, the judgments resulting thence cannot form any general positions to which a chain of reasoning may be fastened, and consequently are not of the nature of axioms, though both similar and equal in respect of evidence.

PART III.-Common Sense.

The third sort is that which ariseth from what hath been termed properly enough, common sense, as being an original

2 The first among the moderns who took notice of this principle, as one of the genuine springs of our knowledge, was Buffier, a French philosopher of the present century, in a book entitled Traité des premières Vérités; one who to an uncommon degree of acuteness in matters of abstraction added that solidity of judgment which hath prevented in him, what had proved the wreck of many great names in philosophy, his understanding becoming the dupe of his ingenuity. This doctrine hath lately, in our own country, been set in the clearest light, and supported by invincible force of argument, by two very able writers in the science of man, Dr. Reid, in his Inquiry into the Human Mind, and Dr. Beattie, in his Essay on the Immutability of Truth. I beg leave to remark in this place, that, though for distinction's sake, I use the term common sense in a more limited signification than either of the authors last mentioned, there appears to be no real difference in our sentiments of the thing itself. I am not ignorant that this doctrine has been lately attacked by Dr. Priestley in a most extraordinary manner, a manner which no man, who has any regard to the name either of Englishman or of philosopher, will ever desire to see imitated, in this or any other country. I have read the performance, but have not been able to discover the author's sentiments in relation to the principal point in dispute. He says expressly, [Examination of Dr. Reid's Inquiry, &c. p. 119,] "Had these writers," Messieurs Reid, Beattie, and Oswald, "assumed as the elements of their common sense certain truths which are so plain that no man could doubt of them, (without entering into the ground of our assent to them,) their conduct would have been liable to very little objection.” And is not this the very thing which these writers have done? What he means to signify by the parenthesis, (without entering into the ground of our assent to them,)" it is not easy to guess. By a ground of assent to any proposition is commonly understood a reason or argument in support of it. Now, by his own hypothesis, there are truths so plain, that no man can doubt of them. If so, what ground of assent beyond their own plainness ought we to seek; what beside this can we ever hope to find, or what better reason needs be given for denominating such truths the dictates of common sense? If something plainer could be found to serve as evidence of any of them, then this plainer truth would be admitted as the first principle, and the other would be con

source of knowledge common to all mankind. I own, indeed, that in different persons it prevails in different degrees of strength; but no human creature hath been found originally and totally destitute of it, who is not accounted a monster in his kind; for, such, doubtless, are all idiots and changelings. By madness, a disease which makes terrible havoc on the faculties of the mind, it may be in a great measure, but is never entirely lost. sidered as deduced by reasoning. But notwithstanding the mistake in the instance, the general doctrine of primary truths would remain unhurt. It seems, however, that though their conduct would have been liable to very little, it would have been liable to some objection. "All that could have been said would have been, that, without any necessity, they had made an innovation in the received use of the term." I have a better opinion of these gentlemen than to imagine, that if the thing which they contend for be admitted, they will enter into a dispute with any person about the name: though, in my judgment, even as to this, it is not they, but he, who is the innovator. He proceeds," For no person ever denied that there are self-evident truths, and that these must be assumed, as the foundation of all our reasoning. I never met with any person who did not acknowledge this, or heard of any argumentative treatise that did not go on the supposition of it." Now, if this be the case, I would gladly know what is the great point he controverts. Is it, whether such self-evident truths shall be denominated principles of Common Sense, or be distinguished by some other appellation? Was it worth any man's while to write an octavo of near 400 pages, for the discussion of such a question as this? And if, as he assures us, they have said more than is necessary, in proof of a truth which he himself thinks indisputable, was it no more than necessary in Dr. Priestley to compose so large a volume, in order to convince the world that too much had been said already on the subject? I do not enter into the examination of his objections to some of the particular principles produced as primary truths. An attempt of this kind would be foreign to my purpose; besides that the authors he has attacked are better qualified for defending their own doctrine, and no doubt will do it, if they think there is occasion. I shall only subjoin two remarks on this book. The first is, that the author, through the whole, confounds two things totally distinct, certain associations of ideas, and certain judgments implying belief, which, though in some, are not in all cases, and therefore not necessa rily, connected with association. And if so, merely to account for the association is in no case to account for the belief with which it is attended. Nay, admitting his plea, [page 86,] that by the principle of association not only the ideas but the concomitant belief may be accounted for, even this does not invalidate the doctrine he impugns. For, let it be observed that it is one thing to assign a cause which, from the mechanism of our nature, has given rise to a particular tenet or belief, and another thing to produce a reason by which the understanding has been convinced. Now, unless this be done as to the principles in question, they must be considered as primary truths, in respect of the understanding, which never deduced them from other truths, and which is under a necessity, in all moral reasonings, of founding upon them. In fact, to give any other account of our conviction of them is to confirm instead of confuting the doctrine, that in all argumentation they must be regarded as primary truths, or truths which reason never inferred, through any medium, from other truths previously perceived. My second remark is, that though this examiner has, from Dr. Reid, given us a catalogue of first principles, which he deems unworthy of the honourable place assigned them, he has no where thought proper to give us a list of those self-evident truths which, by his own account, and in his own express words, "must be assumed as the foundation of all our reasoning." How much light might have been thrown upon the subject by the contrast? Perhaps we should have been enabled, on the comparison, to discover some distinctive characters n his genuine axioms, which would have preserved us from the danger of confounding them with their spurious ones. Nothing is more evident than that, in whatever regards matter of fact, the mathematical axioms will not answer. These are purely fitted for evolving the abstract relations of quantity. This he in effect owns himself [page 39]. It would have been obliging, then, and would have greatly contributed to shorten the controversy, if he had given us at least a specimen of those self-evident principles, which, in his estimation, are the ne plus ultra of moral reasoning.

It is purely hence that we derive our assurance of such truths as these: "Whatever has a beginning has a cause". "When there is in the effect a manifest adjustment of the several parts to a certain end, there is intelligence in the cause. "The course of nature will be the same to-morrow that it is to-day; or, the future will resemble the past""There is such a thing as body; or, there are material substances independent of the mind's conceptions"-" There are other intelligent beings in the universe beside me"-" The clear representations of my memory, in regard to past events, are indubitably true." These, and a great many more of the same kind, it is impossible for any man by reasoning to evince, as might easily be shown, were this a proper place for the discussion. And it is equally impossible, without a full conviction of them, to advance a single step in the acquisition of knowledge, especially in all that regards mankind, life, and conduct.

I am sensible that some of these, to men not accustomed to inquiries of this kind, will appear at first not to be primary principles, but conclusions from other principles; and some of them will be thought to coincide with the other kinds of intuition above mentioned. Thus the first, "Whatever hath a beginning hath a cause," may be thought to stand on the same footing with mathematical axioms. I acknowledge that in point of evidence they are equal, and it is alike impossible, in either case, for a rational creature to withhold his assent. Nevertheless, there is a difference in kind. All the axioms in mathematics are but the enunciations of certain properties in our abstract notions, distinctly perceived by the mind, but have no relation to any thing without themselves, and can never be made the foundation of any conclusion concerning actual existence; whereas, in the axiom last specified, from the existence of one thing we intuitively conclude the existence of another. This proposition, however, so far differs, in my apprehension, from others of the same order, that I cannot avoid considering the opposite assertion as not only false but contradictory; but I do not pretend to explain the ground of this difference.

The faith we give to memory may be thought, on a superficial view, to be resolvable into consciousness, as well as that we give to the immediate impressions of sense. But on a little attention one may easily perceive the difference. To believe the report of our senses doth indeed commonly imply to believe the existence of certain external and corporeal objects, which give rise to our particular sensations. This, I acknowledge, is a principle which doth not spring from consciousness, (for consciousness cannot extend beyond sensation,) but from common sense, as well as the assurance we have in the report of memory. But this was not intended to be included under

the second branch of intuitive evidence. By that firm belief in sense, which I there resolved into consciousness, I meant no more than to say, I am certain that I see, and feel, and think, what I actually see, and feel, and think. As in this I pronounce only concerning my own present feelings, whose essence consists in being felt, and of which I am at present conscious, my conviction is reducible to this axiom, or coincident with it," It is impossible for a thing to be and not to be at the same time." Now when I say, I trust entirely to the clear report of my memory, I mean a good deal more than, "I am certain that my memory gives such a report, or represents things in such a manner," for this conviction I have indeed from consciousness; but I mean, "I am certain that things happened heretofore at such a time, in the precise manner in which I now remember that they then happened." Thus there is a reference in the ideas of memory to former sensible impressions, to which there is nothing analogous in sensation. At the same time it is evident, that remembrance is not always accompanied with this full conviction. describe, in words, the difference between those lively signatures of memory, which command an unlimited assent, and those fainter traces which raise opinion only, or even doubt, is perhaps impracticable; but no man stands in need of such assistance to enable him in fact to distinguish them, for the direction of his own judgment and conduct. Some may imagine that it is from experience we come to know what faith in every case is due to memory. But it will appear more fully afterwards, that unless we had implicitly relied on the distinct and vivid informations of that faculty, we could not have moved a step towards the acquisition of experience. It must, however, be admitted, that experience is of use in assisting us to judge concerning the more languid and confused suggestions of memory; or, to speak more properly, concerning the reality of those things, of which we ourselves are doubtful whether we remember them or not.

To

In regard to the primary truths of this order, it may be urged that it cannot be affirmed of them all at least, as it may of the axioms in mathematics, or the assurances we have from consciousness, that the denial of them implies a manifest contradiction. It is, perhaps, physically possible that the course of nature will be inverted the very next moment; that my memory is no other than a delirium, and my life a dream; that all is mere illusion; that I am the only being in the universe, and that there is no such thing as body. Nothing can be juster than the reply given by Buffier, "It must be owned, says he3, "that to maintain propositions, the reverse of the

3 Premières Vérités, Part i. Chap. xi.