stantly requisite. It is evident that the part of his body which supports the object is never wholly at rest; otherwise the object would no more stand upon it, than if placed in the same position upon a table. The equilibrist, therefore, must watch, in the very beginning, every inclination of the object from the proper position, in order to counteract this inclination by a contrary movement. In this manner the object has never time to fall in any one direction, and is supported in a way somewhat analogous to that in which a top is supported on a pivot, by being made to spin upon an axis.

2. That a person should be able to do this in the case of a single object, is curious; but that he should be able to balance, in the same way, two, three, nay, half a dozen of objects, upon different parts of his body, and at the same time balance himself on a small cord or wire, is indeed wonderful. Nor is it possible to conceive, that in such an instance, the mind, at one and the same moment, attends to these equilibriums; for it is not merely the attention which is requisite, but the eye. We must therefore conclude, that both the attention and the eye are directed successively to the different equilibriums, but change from one object to another with such velocity, that the effect, with respect to the experiment, is the same as if they were directed to all the objects constantly.

Corol. This last illustration affords direct evidence, as Mr. Stewart observes, of the possibility of our exerting acts of the will, which we are unable to recollect; for the movements of the equilibrist do not succeed each other in regular order, like those of the harpsichord player, in performing a piece of music; but must, in every instance, be regulated by accidents, which may vary in numberless respects, and which indeed must vary in numberless respects every time he repeats the experiment; and, therefore, though, in the case of the musician, we should suppose that the motions cling to one another, and to the impressions of the notes, in the way of association, without any intervention in the state of mind called will, yet, in this instance of the equilibrist, even the possibility of such a supposition is directly contradicted by the fact which has been established.

132. The faculty of attention is susceptible of much improvement, as may be established from the well-known fact, that a person who accidentally loses his sight, never fails to improve gradually in the sensibility of his touch.

Illus. Now there are only two ways of explaining this. The one is, that, in consequence of the loss of the one sense, some change takes place in the physical constitution of the body, so as to improve a different organ of perception. The other is, that the mind gradually acquires a power of attending to and remembering those slighter sensations of which it was formerly conscious, but which, from habits of inattention, made no impression whatever on the memory. No one, surely, can hesitate, for a moment, in pronouncing which of these two suppositions is the more philosophical.

133. Hitherto we have treated only of those habits in which both mind and body are concerned; but there are

phenomena purely intellectual, that are explicable on the same principles.

Illus. 1. Every person who has studied the elements of geometry, must have observed many cases in which the truth of a theorem struck him the moment he heard the enunciation; yet he might not be able to state immediately to others upon what his conviction was founded; but there can be no doubt but that, before he gave his assent to the theorem, a process of thought passed through the mind, but passed so quickly, that he could not, without difficulty, arrest his ideas in their rapid succession, and state them to others in their proper and logical order.

134. In politics, in morals, and in common life, many questions daily occur, in considering which, we almost instantaneously see where the truth lies, although we are not in a condition, all at once, to explain the grounds of our conviction. But even in those cases in which the truth of a proposition seems to strike us instantaneously, although we may not be able, at first, to discover the media of proof, we seldom fail in the discovery by perseverance. And nothing contributes so much to form this talent as that study which has the operations of the mind for its object; for, by habituating us to reflect on the subjects of our consciousness, it enables us to retard, in a considerable degree, the current of thought; to arrest many of those ideas which would otherwise escape our notice; and to render the arguments which we employ for the conviction of others, an exact transcript of those trains of inquiry and reasoning, which originally led us to form our opinions.

135. Men of business, who are under the necessity of thinking and deciding on the spur of the occasion, are led to cultivate, as much as possible, a quickness in their mental operations; and sometimes acquire it in so great a degree, that their judgments seem to be almost intuitive. A stockjobber knows this.

Obs. And the greatest generals, in new and untried difficulties, in the midst of battle, have, with a quickness that astonished all around them, decided upon movements no less hazardous than successful. Now, long practice in the field might give them the power of carrying on certain intellectual processes concerning modes of attack and defence, but the reasonings by which their judgments were swayed, in those particular instances we have alluded to, consisted only of a few steps, which, as soon as the intellectual process was finished, vanished, perhaps forever, entirely from the memory.

136. On the other hand, men of speculation, who have not merely to form opinions for themselves, but to communicate them to others. find it necessary to retard the train

a

of thought as it passes in the mind, so as to be able afterwards to recollect every different step of the process; habit which, in some cases, has such an influence on the intellectual powers, that there are men who, even in their private speculations, not only make use of words as an instrument of thought, but form these words into regular sen

tences.

137. When a train of thought leads to any interesting conclusion, or excites any pleasant feeling, it becomes peculiarly difficult to arrest our fleeting ideas, because the mind has little inclination to retrace the steps by which it arrived at the pleasure which it now feels.

Obs. This is one great cause of the difficulty attending philosophical criticism; and exquisite sensibility, so far from being useful in this species of criticism, both gives a disrelish for the study and disqualifies for pursuing it legitimately.

138. There is a great variety of cases, in which the mind apparently exerts different acts of attention at once; but from the illustrations which we have given of the astonishing rapidity of thought, it is obvious, that those acts are not coexistent; or, in other words, that we do not attend, at one and the same instant, to objects which we can attend to separately.

Illus. 1. The case of the equilibrist and rope-dancer affords direct evidence of the possibility of the mind's exerting different successive acts in an interval of time so short, as to produce the same sensible effect as if they had been exerted at one and the same moment. In this case, every movement of the eyes precedes a thought of the mind, every thought a volition, every volition a separate action of muscular force, but so rapidly does each of these succeed the other, that though they seem instantaneous, they cannot be mathematically coexistent.

2. In a concert of music, a good ear can attend to the different parts of the music separately, or can attend to them all at once, and feel the full effect of the harmony; but the mind is constantly varying its attention from one part of the music to the other, and its operations are so rapid as to give us no perception of an interval of time.

3. In viewing a picture, the mind at one and the same time perceives every point in the outline of the object (provided the whole be painted on the retina at one and the same instant), for perception, like consciousness, is an involuntary operation; but as no two points of the outline are in the same direction, every point, by itself, constitutes just as distinct an object of attention to the mind, as if it were separated by an interval of empty space from all the rest. As, therefore, it is impossible for the mind to attend to more than one of those points at once, and as the perception of the

figure of the object implies a knowledge of the relative situation of the different points with respect to each other, we must conclude that the perception of the figure by the eye, is the result of a number of different acts of attention. These acts of attention, however, are performed with such rapidity, that the effect, with respect to us, is the same as if the perception were instantaneous.

Corol. 1. If the perception of visible figure were an immediate consequence of the picture on the retina, we should have, at the first glance, as distinct an idea of a figure of a thousand sides, as of a triangle or a square; for when the figure is very simple, the process of the mind is so rapid, that the perception seems to be instantaneous; but when the sides are multiplied beyond a certain number, the interval of time necessary for these different acts of attention becomes perceptible.

2. If these reasonings be admitted, it will follow, that without the faculty of memory, we could have no perception of visible figure.

CHAPTER V.

OF CONCEPTION.

139. CONCEPTION is that faculty of the mind which enables us to form a notion of an absent object of perception; or of a sensation which it has formerly felt.

Illus. When a painter paints a picture of a friend who is absent or dead, he is commonly said to paint from memory; and the expression is sufficiently correct for common conversation. But, in an analysis of the powers of the mind, there is ground for a distinction between conception and the other powers, with some of which it is often confounded. The power of conception enables the painter to make the features of his friend an object of thought, so as to copy the resemblance; the power of memory recognizes these features as a former object of perception. Thus, conception is distinguished from memory. Every act of memory includes an idea of the past; conception implies no idea of time whatever.

Note. Shakspeare calls this power the mind's eye.

Hamlet. My father! Methinks I see my father.
Horatio. Where, my lord?

Hamlet. In my mind's eye, Horatio.

HAMLET, Act 1. Scene 4.

140. Conception corresponds, according to the view we have taken of it, to what the schoolmen call simple apprehension; with this difference only, that they include, under this name, our apprehension of general propositions; whereas the word conception is, in this volume, limited to our sensations and the objects of our perceptions.

Illus. This distinction is warranted by the authority of philosophers in a case perfectly analogous. Thus, in ordinary language, we apply the same word perception to the knowledge which we have by our senses of external objects, and to our knowledge of a speculative truth. And between the conception of a truth, and the conception of an absent object of sense, there is obviously as wide a difference as between the perception of a tree and the perception of a mathematical theorem. Conception, therefore, is that faculty whose province it is to enable us to form a notion of our past sensations, or of the objects of sense that we have formerly perceived.

141. Conception is frequently used as synonymous with imagination, but imagination is distinguished from conception as a part from a whole.

Illus. The business of conception is to present us with an exact transcript of what we have felt or perceived. But we have, moreover, a power of modifying our conceptions, by combining the parts of different conceptions together, so as to form new wholes of our own creation. This power, according to Mr. Stewart, is expressed by the word imagination; and he apprehends, that this is the proper sense of the word; if imagination be the power which gives birth to the productions of the poet and the painter. This is not a simple faculty of the mind, for it presupposes abstraction, to separate from each other qualities and circumstances which have been perceived in conjunction; and also judgment and taste to direct us, in forming the combinations.

Obs. People, in common discourse, often use the phrase thinking upon an object, to express what we have illustrated as the conception of it. Shakspeare, whose talent for philosophizing was equal to his imaginative powers as a poet, uses, in the following passage, the former of these phrases in the same sense as we should use conception, and the words imagination and apprehension are synonyinous with each other.

-Who can hold a fire in his hand
By thinking on the frosty Caucasus ?
Or cloy the hungry edge of appetite
By bare imagination of a feast?
Or wallow naked in December's snow,
By thinking on fantastic summer's heat?
Oh no! the apprehension of the good
Gives but the greater feeling to the worse.
K. RICHARD II. Act 1. Scene 6.

142. We can conceive the objects of some senses much more easily than those of others. And, first, as to visible objects; we can conceive the structure of a building that is familiar to us much more easily than a particular sound, a particular taste, or a particular pain which we have formerly felt.

Illus. The peculiarity in the case of visible objects seems to arise from this; that when we think of a sound or of a taste, the object