"application one to another, to perceive their agreement "or disagreement, it is fain, by the intervention of other “ideas one or more as it happens) to discover the agree"ment or disagreement which it searches; and this is "that which we call reasoning."* According to these definitions, supposing the equality of two lines A and B to be perceived immediately in consequence of their coincidence; the judgment of the mind is intuitive: supposing A to coincide with B, and B with C; the relation between A and C is perceived by reasoning. Nor is this a hasty: inference from Locke's accidental language. That it is perfectly agreeable to the foregoing definitions, as understood by their author, appears from the following passage, which occurs afterwards: "The principal act of ratioci"nation is the finding the agreement or disagreement of "two ideas, one with another, by the intervention of a “third. As a man, by a yard, finds two houses to be of "the same length, which could not be brought together to measure their equality by juxta-position."+

This use of the words intuition and reasoning, is surely somewhat arbitrary. The truth of mathematical axioms. has always been supposed to be intuitively obvious; and the first of these, according to Euclid's enumeration, affirms, That if A be equal to B, and B to C, A and C are equal. Admitting, however, Locke's definition to be just, it only tends to confirm what has been already stated with respect to the near affinity, or rather the radical identity of intuition and of reasoning. When the relation of equality between A and B has once been perceived, A and B are completely identified as the same mathematical quantity; and the two letters may be regarded as synonymous wherever they occur. The faculty, therefore, which perceives the relation between A and C, is the same with the

* B. IV. chap. ii. §§ 1. and 2.

B. IV. chap. xvii. 18.

faculty which perceives the relation between A and B, and between B and C.*

In farther confirmation of the same proposition, an appeal might be made to the structure of syllogisms. Is it possible to conceive an understanding so formed as to perceive the truth of the major and of the minor propositions, and yet not to perceive the force of the conclusion? The contrary must appear evident to every person who knows what a syllogism is; or rather, as in this mode of stating an argument, the mind is led from universals to particulars, it must appear evident, that, in the very statement of the major proposition, the truth of the conclusion is presupposed; insomuch, that it was not without good reason Dr. Campbell hazarded the epigrammatic, yet unanswerable remark, that "there is always some radical de"fect in a syllogism, which is not chargeable with that species of sophism known among logicians by the name "of petitio principii, or a begging of the question."†

The idea which is commonly annexed to intuition, as opposed to reasoning, turns, I suspect, entirely on the circumstance of time. The former we conceive to be instantaneous; whereas the latter necessarily involves the notion of succession, or of progress. This distinction is sufficiently precise for the ordinary purposes of discourse; nay, it supplies us, on many occasions, with a convenient phraseology: but, in the theory of the mind, it has led to some mistaken conclusions, on which I intend to offer a few remarks in the second part of this section.

* Dr. Reid's notions, as well as those of Mr. Locke, seem to have been somewhat unsettled with respect to the precise line which separates intuition from reasoning. That the axioms of geometry are intuitive truths, he has remarked in numberless passages of his works; and yet, in speaking of the application of the syllogistic theory to mathematics, he makes use of the following expression :" "The simple reasoning, ‘A is equal to B, and B to C, therefore A is equal to C,' cannot be brought into any syllogism in figure and mode."-See his Analysis of Aristotle's Logic.

Phil. of Rhet. Vol. I. p. 174. [Boston edit. p. 93.J

So much with respect to the separate provinces of these powers, according to Locke ;-a point on which I am, after all, inclined to think, that my own opinion does not differ essentially from his, whatever inferences to the contrary may be drawn from some of his casual expressions. The misapprehensions into which these have contributed to lead various writers of a later date, will, I hope, furnish a sufficient apology for the attempt which I have made, to place the question in a stronger light than he seems to have thought requisite for its illustration.

In some of the foregoing quotations from his Essay, there is another fault of still greater moment; of which, although not immediately connected with the topic now under discussion, it is proper for me to take notice, that I may not have the appearance of acquiescing in a mode of speaking so extremely exceptionable. What I allude to is, the supposition which his language, concerning the powers both of intuition and of reasoning, involves, that knowledge consists solely in the perception of the agreement or the disagreement of our ideas. The impropriety of this phraseology has been sufficiently exposed by Dr. Reid, whose animadversions I would beg leave to recommend to the attention of those readers, who, from long habit, may have familiarized their ear to the peculiarities of Locke's philosophical diction. In this place, I think it sufficient for me to add to Dr. Reid's strictures, that Mr. Locke's language has, in the present instance, been suggested to him by the partial view which he took of the subject; his illustrations being chiefly borrowed from mathematics, and the relations about which it is conversant. When applied to these relations, it is undoubtedly possible to annex some sense to such phrases as comparing ideas, the juxta-position of ideas,—the perception of the agreements or disagreements of ideas; but, in

most other branches of knowledge, this jargon will be found, on examination, to be altogether unmeaning; and, instead of adding to the precision of our notions, to involve plain facts in technical and scholastic mystery.

This last observation leads me to remark farther, that even when Locke speaks of reasoning in general, he seems, in many cases, to have had a tacit reference, in his own mind, to mathematical demonstration; and the same criticism may be extended to every logical writer whom I know, not excepting Aristotle himself. Perhaps it is chiefly owing to this, that their discussions are so often of very little practical utility; the rules which result from them being wholly superfluous, when applied to mathematics; and, when extended to other branches of knowledge, being unsusceptible of any precise, or even intelligible interpretation.

SECTION I.

II.

Conclusion obtained by a Process of Deduction often mistaken for Intuitive Judgments.

IT has been frequently remarked, that the justest and most efficient understandings are often possessed by men who are incapable of stating to others, or even to themselves, the grounds on which they proceed in forming their decisions. In some instances, I have been disposed to ascribe this to the faults of early education; but, in other cases, I am persuaded, that it was the effect of active and imperious habits in quickening the evanescent processes of thought, so as to render them untraceable by the memory; and to give the appearance of intuition to what was in fact the result of a train of reasoning so rapid as to

escape notice. This I conceive to be the true theory of what is generally called common sense, in opposition to book-learning; and it serves to account for the use which has been made of this phrase, by various writers, as synonymous with intuition.

These seemingly instantaneous judgments have always appeared to me as entitled to a greater share of our confidence than many of our more deliberate conclusions; inasmuch as they have been forced, as it were, on the mind by the lessons of long experience; and are as little liable to be biassed by temper or passion, as the estimates we form of the distances of visible objects. They constitute, indeed, to those who are habitually engaged in the busy scenes of life, a sort of peculiar faculty, analogous, both in its origin and in its use, to the coup d'oeil of the military engineer, or to the quick and sure tact of the medical practitioner, in marking the diagnostics of disease.

For this reason, I look upon the distinction between our intuitive and deductive judgments as, in many cases, merely an object of theoretical curiosity. In those simple conclusions which all men are impelled to form by the necessities of their nature, and in which we find an uni formity not less constant than in the acquired perceptions of sight, it is of as little consequence to the logician to spend his time in efforts to retrace the first steps of the infant understanding, as it would be to the sailor or the sportsman to study, with a view to the improvement of his eye, the Berkeleian theory of vision. In both instances, the original faculty and the acquired judgment are equally entitled to be considered as the work of Nature; and in both instances we find it equally impossible to shake off her authority. It is no wonder, therefore, that, in popular language, such words as common sense and reason should be used with a considerable degree of latitude;