time, there coëxist with it, and with it perish, many minima of sound which, ex hypothesi, are not perceived, are not heard, as not attended to. In a concert, therefore, on this doctrine, a small number of sounds only could be perceived, and above this petty maximum, all sounds would be to the ear as zero. But what is the fact? No concert, however numerous its instruments, has yet been found to have reached, far less to have surpassed, the capacity of mind and its organ.

Impossible, on Stewart's doctrine, to understand how we can perceive the relation of different sounds.

de se.

But it is even more impossible, on this hypothesis, to understand how we can perceive the relation of different sounds, that is, have any feeling of the harmony of a concert. In this respect, it is, indeed, felo It is maintained that we cannot attend at once to two sounds, we cannot perceive them as coëxistent, consequently, the feeling of harmony of which we are conscious, must proceed from the feeling of the relation of these sounds as successively perceived in different points of time. We must, therefore, compare the past sound, as retained in memory, with the present, as actually perceived. But this is impossible on the hypothesis itself. For we must, in this case, attend to the past sound in memory, and to the present sound in sense at once, or they will not be perceived in mutual relation as harmonic. But one sound in memory and another sound in sense, are as much two different objects as two different sounds in sense. Therefore, one of two conclusions is inevitable, either we can attend to two different objects at once, and the hypothesis is disproved, or we cannot, and all knowledge of relation and harmony is impossible, which is absurd.

His second illustration from the phænomena of vision.

The consequences of this doctrine are equally startling, as taken from Mr. Stewart's second illustration from the phænomena of vision. He holds that the perception of figure by the eye is the result of a number of separate acts of attention, and that each act of attention has for its object a point the least that can be seen, the minimum visibile. On this hypothesis, we must suppose that, at every instantaneous opening of the eyelids, the moment sufficient for us to take in the figure of the objects comprehended in the sphere of vision, is subdivided into almost infinitesimal parts, in each of which a separate act of attention is performed. This is, of itself, sufficiently inconceivable. But this being admitted, no difficulty is removed. The separate acts must be laid up in memory, in imagination. But how are they there to form a single whole,

unless we can, in imagination, attend to all the minima visibilia together, which in perception we could only attend to severally? On this subject I shall, however, have a more appropriate occasion of speaking, when I consider Mr. Stewart's doctrine of the relation of color to extension.

LECTURE XIV.

CONSCIOUSNESS,-ATTENTION IN GENERAL.

In the former part of our last Lecture, I concluded the argument against Reid's analysis of Consciousness Recapitulation. into a special faculty, and showed you that, even in relation to Perception, (the faculty by which we obtain a knowledge of the material universe,) Consciousness is still the common ground in which every cognitive operation has its root. I then proceeded to prove the same in regard to Attention. After some observations touching the confusion among philosophers, more or less extensive, in the meaning of the term reflection, as a subordinate modification of attention, I endeavored to explain to you. what attention properly is, and in what relation it stands to consciousness. I stated that attention is consciousness applied to an act of will or desire under a particular law. In so far as attention is an act of the conative faculty, it is not an act of knowledge at all, for the mere will or desire of knowing is not an act of cognition. But the act of the conative faculty is exerted by relation to a certain law of consciousness, or knowledge, or intelligence. This law, which we call the Law of Limitation, is, that the intension of our knowledge is in the inverse ratio of its extension,-in other words, that the fewer objects we consider at once, the clearer and more distinct will be our knowledge of them. Hence the more vividly we will or desire that a certain object should be clearly and distinctly known, the more do we concentrate consciousness through some special faculty upon it. I omitted, I find, to state that I think Reid and Stewart incorrect in asserting that attention is only a voluntary act, meaning by the expression voluntary, an act of freewill. I am far from maintaining, as Brown and others do, that all will is desire; but still I am persuaded that we are frequently determined to an act of attention, as to many other acts, independently of our free and deliberate volition. Nor is it, I conceive, possible to hold that, though immediately determined to

Attention possible without an act of freewill.

an act of attention by desire, it is only by the permission of our will that this is done; consequently, that every act of attention is still under the control of our volition. This I cannot maintain. Let us take an example:- When occupied with other matters, a person may speak to us, or the clock may strike, without our having any consciousness of the sound; but it is wholly impossible for us to remain in this state of unconsciousness intentionally and with will. We cannot determinately refuse to hear by voluntarily withholding our attention; and we can no more open our eyes, and, by an act of will, avert our mind from all perception of sight, than we can, by an act of will, cease to live. We may close our ears or shut our eyes, as we may commit suicide; but we cannot, with our organs unobstructed, wholly refuse our attention at will. It, therefore, appears to me the more correct doctrine to hold that there is no consciousness without attention, without concentration, but that attention is of three degrees or kinds. The first, a mere vital and irresistible act; the second, an act determined by desire, which, though involuntary, may be resisted by our will; the third, an act determined by a deliberate volition. An act of attention, that is, an act of concentration, seems thus necessary to every exertion of consciousness, as a certain contraction of the pupil is requisite to every exercise of vision. We have formerly noticed, that discrimination is a condition of consciousness; and a discrimination is only possible by a concentrative act, or act of attention. This, however, which corresponds to the lowest degree, to the mere vital or automatic act of attention, has been refused the name; and attention, in contradistinction to this mere automatic contraction, given to the two other degrees, of which, however, Reid only recognizes the third.

Attention of three degrees or kinds.

Attention, then, is to consciousness, what the contraction of the

Nature and importance of attention.

pupil is to sight; or to the eye of the mind, what the microscope or telescope is to the bodily eye. The faculty of attention is not, therefore, a special faculty, but merely consciousness acting under the law of limitation to which it is subjected. But whatever be its relations to the special faculties, attention doubles all their efficiency, and affords them a power of which they would otherwise be destitute. It is, in fact, as we are at present constituted, the primary condition of their activity.

Having thus concluded the discussion of the question regarding the relation of consciousness to the other cognitive faculties, I

Reid,

1 See Reid, Active Powers, Essay ii. ch. 3. Works, p. 587.-ED.

Can we attend to more than a single object at once?

proceeded to consider various questions, which, as not peculiar to any of the special faculties, fall to be discussed under the head of consciousness, and I commenced with the curious problem, Whether we can attend to more than a single object at once. Mr. Stewart maintains, though not without hesitation, the negative. I endeavored to show you that his arguments are not conclusive, and that they even involve suppositions which are so monstrous as to reduce the thesis he supports ad impossibile. I have

Brown's doctrine, that the mind cannot exist at the same moment in two different states.

This doctrine maintained by Locke.

now only to say a word in answer to Dr. Brown's assertion of the same proposition, though in different terms. In the passage I adduced in our last Lecture, he commences by the assertion, that the mind cannot exist, at the same moment, in two different states,- that is, in two

states in either of which it can exist separately, and concludes with the averment that the contrary supposition is a manifest absurdity. I find the same doctrine maintained by Locke in that valuable, but neglected, treatise entitled An Examination of Père Malebranche's Opinion of Seeing all Things in God. In the thirty-ninth section he says: "Different sentiments are different modifications of the mind. The mind or the soul that perceives, is one immaterial, indivisible substance. Now, I see the white and black on this paper, I hear one singing in the next room, I feel the warmth of the fire I sit by, and I taste an apple I am eating, and all this at the same time. Now, I ask, take modification for what you please, can the same unextended, indivisible substance have different, nay, inconsistent and opposite, (as these of white and black must be,) modifications at the same time? Or must we suppose distinct parts in an indivisible substance, one for black, another for white, and-another for red ideas, and so of the rest of those infinite sensations which we have in sorts and degrees; all which we can distinctly perceive, and so are distinct ideas, some whereof are opposite as heat and cold, which yet a man may feel at the same time?" Leibnitz has not only given a refutation of Locke's Essay, but likewise of his Examination of Malebranche. In reference to the passage I have just quoted Leibnitz says: "Mr. Locke asks, 'Can the same unextended, indivisible substance, have different, nay, inconsistent and opposite modifications, at the same time?' I reply, it can. What is inconsistent in the same object, is not inconsistent in the representation of different objects which we conceive at the same moment. For

nitz.

Opposed by Leib