black; or, which is a proposition of the same kind, that white is white and black is black, I affirm what I know intuitively. The colours of white and of black have excited ideas in my mind, which, whenever they occur, must be identic and true to themselves; for it is not possible for me to have any other idea of white than white, or of black than black: the agreement in this case is the AGREEMENT OF INDENTITY, the agreement of either idea with itself; and hence the man who asks me to prove that white is white, or that white is not black, or red, or yellow, asks me to prove what I neither can prove nor want to prove. I do not want to prove it, for I know it with certain knowledge, or, in other words, it is SELF-EVIDENT. And I cannot prove it for this reason; that every proof consists in placing between two ideas that we want to unite together by an agreement which we do not perceive an idea whose agreement with both of them is more obvious. But what idea can I place by the side of the idea of white, of black, of red, or of yellow, that can agree more fully with either of these ideas than such ideas agree with themselves? Every one must see that there is no such idea to be had; and, consequently, that I can neither offer a proof nor want one. And the very attempt to obtain such a proof would be an absurdity: for could it possibly be acquired, it would not add to my knowledge, which is perfect and certain already, and depends upon the constant agreement of the idea with itself-the agreement of identity. Nothing has been productive of more mischief in the science of metaphysics than this absurd restlessness in seeking after proofs in cases of intuition, where no proofs are to be had, and the knowledge is certain without them. M. Des Cartes's hypothesis, as I had occasion to notice in our last lecture, commences with an instance of this very absurdity, and it has proved the ruin of it; and the same attempt in various other hypotheses of later date that we shall yet have to touch upon, and particularly those of Bishop Berkeley and Mr. Hume, has equally proved the ruin of these. When I affirm that 1 am, I affirm that of which I have an intuitive knowledge: and when I affirm that I think, I only make a proposition of the same kind. The connexion between the two ideas I am, and the two ideas I think, is a connexion of coexistence or absolute necessity. It is not possible to separate them, and they want no third or intervening idea to unite them; for if it were possible for me to doubt whether I thought, or whether I existed, the very doubt itself would answer the purpose of a proof in either case. Now one of the chief absurdities of M. Des Cartes's argument, I think, therefore I am, consists in his putting two propositions equally self-evident and intuitive by the side of each other, and making the first the proof of the second: for being equally intuitive, the second must be just as good a proof of the first as the first is of the second; since the mind can no more put together the two ideas I am without thinking, than it can put together the two ideas I think, without being. But nothing is gained by their being put together in the way of proof or demonstration; for I have no more evidence of my existence by calling up the ideas I think, than I had before this proposition was conceived; and hence the attempt not only fails, but could lead to no use if it could stand its ground. Our knowledge of personal identity is derived from the same source. is INTUITIVE. This is a subject which has excited a great deal of learned controversy, and called forth many a different proof, or attempt at proof, from the different disputants who have engaged in it. Mr. Locke himself, with a singular deviation from the principles of his own system, has fallen into a common error and offered as a proof the idea of consciousness. No proof, however, or attempt at proof, is more imperfect; for the identity often continues when the consciousness is interrupted, as in sleep without dreaming, in apoplexy, catalepsy, drowning, and various other cases: and hence, if identity were dependent on consciousness, the same man in a dead sleep and out of it would be two or more different persons. The truth is, that our knowledge of identity is intuitive; the two ideas I am, and the two ideas I was, a combination of which constitutes the more complex idea of personal identity, are ideas of necessary connexion from the first moment the connexion can be formed: and hence they produce certain knowledge, and can have no proof; since It there can be no intermediate idea capable of possessing a closer connexion with either proposition, and consequently fitted to enter between them. "Here, then," to adopt the language of Bishop Butler, whose reasoning upon this subject bears a close resemblance to the present, "we can go no farther. For it is ridiculous to attempt to prove the truth of those perceptions whose truth we can no otherwise prove than by other perceptions of exactly the same kind with them, and which there is just the same ground to suspect; or to attempt to prove the truth of our faculties, which can no otherwise be proved than by the use or means of those very suspected faculties themselves."* I may now advance a step farther, and observe that in all cases in which the agreement or disagreement of two or more ideas can be immediately perceived and compared together, our knowledge is of a like kind, and consequently approaches to intuitive; although to other persons such ideas may be very remote, and require a long chain of intermediate ideas to connect or separate them, or prove their agreement or repugnancy. Thus I know intuitively, or without going through the process, that the arc of a circle is less than the entire circle; that a circle itself is a line equidistant in every part of it from its centre; that the three angles of a triangle are equal to two right angles; that the square of four is sixteen. No man, however, can, perhaps, have any kind of knowledge at first sight upon any of these subjects; he cannot put the extreme ideas together in such a manner as to perceive their agreement or disagreement, and he is not acquainted with the intermediate ideas which are to compare them, and prove their relation. If he could perceive that relation at first sight, he would at first sight have intuitive knowledge upon the subject; and some persons have a much more comprehensive power of this kind than others; for they can perceive and compare the relations of ideas both more readily and more extensively. Euler was a striking example of this endowment, in regard to the science of abstract quantities: Jedediah Buxton appears to have obtained a similar degree of intuitive knowledge in regard to the science of numbers; and we seem in our own day to have another instance of the same kind in the very extraordinary young calculator from America, not more than eight years old.† In I have already stated, that when we cannot immediately perceive the agreement or disagreement of two or more ideas, which we are desirous of bringing into comparison, we are obliged to seek out for some intervening idea whose agreement or disagreement with them is obvious to us; and I have also stated, that as this general search is the immediate office of the faculty of reason, the knowledge thus obtained is called RATIONAL KNOWLEDGE. many cases we are so fortunate as to hit upon intervening ideas whose connexion with the one, the other, or both, as in a chain of perfect evidence, is clear and distinct; and in such case, whether the reasoning consist of a single step or of many, as soon as the mind is able to perceive the connexion or repugnancy, the agreement or disagreement, of the ideas in question, the degree of rational knowledge hereby obtained becomes equal, or nearly so to INTUITION, and is called DEMONSTRATION. If the proofs, or intervening ideas, do not quite amount to this, we have necessarily an inferior degree of rational knowledge, and we distinguish it by the name of BElief, assent, or OPINION; and according to the nature of the proofs or intermediate ideas, as decided by the faculty of the judgment, the opinion is rendered INDURITABLE, PROBABLE, CONJECTURAL, or SUSPICIOUS. It is upon this comparison of two ideas, by means of a mediate idea expressed or understood, that most of our moral information or common knowledge would be found to depend, if we were to analyze it. Thus, on going into the street, and hearing a man whom I am acquainted with asking which is the way to London Bridge, I may, perhaps, observe to a by-stander, "That man ought to know the way." The by-stander immediately compares the two *Analogy of Religion, Natural and Revealed. Of Personal Identity, forming Diss. I. † See "Some account of Zerah Colburn, an American child, who possesses some very remarkable pow ers of solving questions in arithmetic, by computation without writing, or any visible contrivance."→→ Nicholson's Journal of Nat. Phil. vol. xxxiv. p. 5. 66 66 ideas of going to London Bridge, and the man's right to know the way, but can find no connexion or agreement between them, and consequently is ignorant of what I mean. He applies to me, therefore, for the intermediate idea by the question, “ Why so?" and I give it to him by answering, “ Because he has repeatedly been the same road before:" and although he does not put the three ideas into the measured form of the schools, which is called a syllogism, every one as regularly passes through his mind, and gives him the same satisfactory information as if they were to assume such order; in which case they would perhaps run as follows: Every man who goes repeatedly the same road should know his way; It would be absurd to introduce this part of logical analysis into common discourse: but it is of high use in the closet, as teaching us precision, by compelling us to measure the force and value of every idea and word of which a proposition consists. We are indebted to Aristotle for its invention: and though it was at one time carried to an absurd excess, it has of late years been far too generally discontinued. The connective or intermediate idea is not always expressed either in speaking or writing; and hence is not always obvious to the hearer or reader, though it is, or ought to be, so to the framer of the argument. Let me exercise the ingenuity of the audience before me by throwing out as a trial, the following well-known sentiment of Mr. Pope : Who governs freemen should himself be free. Here are two distinct propositions; and Dr. Johnson, not immediately perceiving their agreement, nor immediately hitting upon any intervening idea or proposition by which they might be united, declared the whole to be a riddle, and that the poet might just as well have written, Who drives fat oxen should himself be fat. Had Johnson, however, lived in our own day, and turned his attention to the Continent, it would have been a riddle to him no longer; for he would have called to mind, as I doubt not every one before me has done already, the mischief that has happened to many a free people on the Continent, from the unfortunate want of freedom in the sovereign who is placed over them, and his being under the detestable control of one of the worst, and, unluckily, one of the most universal, tyrants the world has ever witnessed. He would have been, as every one before me must be, at once prepared to have connected the two ideas of freemen,-and the propriety of their being governed by a free sovereign, by means of a third or intervening idea to this effect, that otherwise the people themselves might run no small risk of having their freedom destroyed by foreign force; the whole of which might assume the following appearance if reduced to the form of a syllogism: Therefore, Who governs freemen should be able to maintain their freedom: Who governs freemen should himself be free. PROPER OF REAL KNOWLEDGE, then, is of two kinds or degrees, INTUITION and DEMONSTRATION; below which, all the information we possess is imperfect knowledge or OPINION. Mr. Locke, nevertheless, out of courtesy to the Cartesian hypothesis, rather than from any other cause, makes proper or real •Napoleon Buonaparte. This lecture was delivered in 1814. knowledge to consist of three degrees, placing sensible knowledge, or that obtained by an exercise of the external senses, below the two degrees of intuition and demonstration, though above the authority of opinion. In most instances, however, the ideas we obtain from the senses are as clear and as identic as those obtained from any other source: and in all such cases the knowledge they produce is self-evident or intuitive. And although, at times, the idea excited by a single sense may not be perfectly clear, yet, as we usually correct it, or destroy the doubt which accompanies it, by having recourse to another sense, which furnishes us with the proof or intermediate idea, the knowledge obtained, even in these cases, though not amounting to intuition, is of the nature of demonstration: whence all sensible knowledge (the organs of sense being in themselves perfect, and the objects fully within their scope) falls, if I mistake not, under the one or the other of these two divisions. DEMONSTRATIVE KNOWLEDGE, where the intervening proofs or ideas perform their part perfectly, approaches, as I have already observed, to the certainty of intuition. But it has generally been held that this kind of demonstration can only take place in the science of mathematics, or, in other words, in ideas of number, extension, and figure. I coincide, however, completely with Mr. Locke, in believing that the knowledge afforded by physics may not unfrequently be as certain. I have already stated that the knowledge we possess of our own existence is INTUITIVE. Our knowledge of the existence of a God is, on the contrary, DEMONSTRATIVE. Examine, then, the proofs of this latter knowledge, and see whether it be less certain. Am I asked where proofs to this effect are to be found? On every side they press upon us in clusters.I cannot, indeed, follow them up at the present moment, for it would require a folio volume instead of the close of a single lecture; and I merely throw out the hint that you may pursue it at home. But this I may venture to say, that whatever cluster we take, it will develope to us a certain proof, and, in its separate value, fall but little short of the force of self-evidence. If I ascend into heaven, he is there; in peerless splendour, in ineffable majesty ; diffusing, from an inexhaustible fountain, the mighty tide of light, and life, and love, from world to world, and from system to system. If I descend into the grave, he is there also; still actively and manifestly employed in the same benevolent pursuit: still, though in a different manner, promoting the calm but unceasing career of vitality and happiness; harmoniously leading on the silent circle of decomposition and reorganization: fructifying the cold and gloomy regions of the tomb; rendering death itself the mysterious source of reproduction and new existence; and thus literally making the "dry bones live," and the "dead sing praises" to his name. If I examine the world without me, or the world within me, I trace him equally to a demonstration :-I feel,-nay, more than feel, I know him to be eternal, omniscient, omnipotent, the creator of all things, and therefore God. I discover him, not by the vain maxims of tradition, or the visionary conceit of innate principles, but by the faculty with which he has expressly endowed me to search for him, by my reason. There may, perhaps, be some persons, as well learned as unlearned, who have never brought together these proofs of his existence, and are therefore ignorant of him; as there certainly are others who have never brought together the proofs that the three angles of a triangle are equal to two right angles, and are therefore ignorant of geometry: but both facts have a like truth and a like foundation; both flow from and return to the same fountain: for God is the author of every truth,-for God is truth itself. LECTURE V. ON ANCIENT AND MODERN SKEPTICS. FROM a system that is simple, intelligible, and satisfactory, adapted to the condition of man, and pregnant with useful instruction, we have now to turn our attention to a variety of hypotheses, that are scarcely in any instance worthy of the name of systems, and which it is difficult to describe otherwise than by reversing the terms we have just employed, and characterizing them as complicated, unintelligible, unsatisfactory; as not adapted to the condition of man, and barren of useful instruction. It is a distinguishing and praiseworthy feature in the Essay on Human Understanding, that it confines itself to the subject of human understanding alone, and that, in delineating the operations of the mind, it neither enters into the question of the substance of mind, or the substance of matter; neither amuses us with speculations how external objects communicate with the senses, or the senses with the mental organ. It builds altogether upon the sure foundation of the simple fact, that the senses are influenced, and that they influence the mind; and as, in the former case, it calls the cause of this influence external objects, so in the latter case it calls the effects it produces internal ideas. Of the nature of these objects it says little, but of their substantive existence; of the nature of these ideas it says little, but of their truth or exact correspondence with the objects that excite them; its general view of the subject being reducible to the two following propositions : First, that as objects are perceivable at a distance, and bodies cannot act where they are not, it is evident that something must proceed from them to produce impulse upon the senses, and that the motion hereby excited must be thence continued by the nerves, or connecting chain, to the brain or seat of sensation, so as to produce in our minds the particular ideas we have of them.* And, secondly, that the ideas thus produced, so far from being images or pictures of the objects they represent, have no kind of resemblance to them, except so far as relates to their real qualities of solidity, extension, figure, motion, or rest, and number.t Thus far, and thus far only, does the author of the Essay on Human Understanding indulge in a digression into physical science; and even for this he feels it necessary to offer an apology to his reader: "I hope," says he, “I shall be pardoned this little excursion into natural philosophy, it being necessary in our present inquiry."‡. For myself, I am glad he did not proceed farther, and should have been still more satisfied if he had not proceeded even so far; for the subject proves itself, even in his hands, to be inexplicable; and if he be here found to evince some degree of obscurity, it is only, perhaps, because it is not pos sible to avoid it. Of the PRIMARY or real qualities of bodies, as he denominates them, we know but little; and it is probable, that Mr. Locke has enumerated one or two under this head that do not properly belong to the list. And although it is not difficult to determine his meaning where he asserts that their ideas resemble them, as being drawn from patterns existing in the bodies themselves, the sense of the passage has been very generally mistaken, and opinions have hence been ascribed to him which are contrary to the whole tenor of his system. In consequence of being real representatives of real qualities, they resemble them in respect to REALITY. And this, I think, seems to be what Mr. Locke intended to express upon this subject; though he does not discover his usual clearness as to what he designed to convey by the term RESEMBLANCE. This view, however, will be still more obvious by comparing the seventh, ninth, and twenty-third sections of the Ib. § 13. Ib. $22. •Essay on Hum. Underst. book IL ch. vill. § 12. |