painted on the retina at the same instant, -- for perception, like consciousness, is an involuntary operation.

"As no two points, however, of the outline are in the same direction, every point 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. If the doctrine, therefore, formerly stated be just, it is impossible for the mind to attend to more than one of these 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 figure by the eye is the result of a number of 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.

"In further confirmation of this reasoning, it may be remarked, that 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. The truth is, that, where 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.

"It may, perhaps, be asked, what I mean by a point in the outline of a figure, and what it is that constitutes this point one object of attention. The answer, I apprehend, is, that this point is the minimum visibile. If the point be less, we cannot perceive it; if it be greater, it is not all seen in one direction. If these observations be admitted, it will follow, that, without the faculty of memory, we could have had no perception of visible figure." *

These observations are ingenious, and seem to be in the main sound and instructive. With some exceptions, they are what we should all probably admit on the subject of perception. The exceptions which I would make are these: he supposes perception without attention, and

*Stewart's Philosophy, vol. i. p 78.

on the ground that " perception is an involuntary opera. tion," concludes that "the mind does at one and the same time perceive every point in the outline of the object, provided the whole of it be painted on the retina at the same instant."

Attention is partly voluntary and partly involuntary.* Involuntary, when something is addressed to the sensibilities so urgently as to force attention; voluntary, when the attention is designedly given. Now, the reasons before assigned seem conclusive, that without some attention there can be no perception.

My inference is, "that the mind does" not "at one and the same time perceive every point in the outline of the object," but that its final perception is the result of several combined perceptions.

The only difference between us is, Stewart supposes that the mind perceives "every point in the outline of the object" at once, but does not attend to it; whereas, I suppose the mind does not perceive the whole at once, for the want of the requisite attention. The want of this attention he allows, and therefore, placing attention in the relation of a necessary means of perception, his argument is conclusive in favor of the view which I have maintained.

*This subject has been more fully considered under the head Attention, p. 146.

QUESTIONS ON CHAPTER VI.

What is said of controversies on the subject of perception? What is the only important question at issue? What is said of the greatest truths in science? What is perception, considered as a mental act? What considered as a mental attribute? What is intuitive perception? To what are present inquiries restricted? What are the relative offices of sensation and perception? In how many respects do sensation and perception differ? First? Second? What is an entity? What do entities include? What is a nomentity? Objective entities? Subjective? How do we know the latter?

How, first, do we know the former? How secondly? Illustrate. What perceptions are true? What must we remember? What do we mean when we speak of ideas corresponding with entities? Illustrate. Why do ideas, so unlike their objects, represent them? Remarks. Give examples of true perception. Does perception give the idea, or the idea the perception? What is said of the schoolmen? What are false perceptions? From what may they arise? First cause? Second? Third? Give examples of false perception. What has been one of the most important and disputed points? What have Berkeley and others concluded? What Hume and others? What is now the exact point? What is said of testing perceptions? How are physical entities known? Illustrations? Inference? By what is each entity originally known? What is the greatest source of false perceptions? What must all admit? What may we do after one rense has become accustomed to take the place of another? Examples. What is said of civil courts? How may we test our organs of sense? Example? How may we test the media of perception? Example. Ho may we test the sanity of the mind? What does perception presup pose? Remarks. Other things equal, on what does clearness and ac curacy of attention depend? Is the full perception of an object instantane· ous or gradual? Let the reader examine what is said, and give his own opinion.

13*

CHAPTER VII.

CONCEPTION.

We have now reached the point where we may suppose the ideas of the external world fairly presented to the mind. It is believed that the way has been pointed out, by which we not only obtain our ideas of things around us, but by which we may certainly know that those ideas are correct. The next subject in course is conception. Considered as a mental faculty, it is, in the strictest sense, that power by which we form notions of absent objects of perception and of past sensations.

This definition will be best understood by an example. A man has visited Niagara Falls, and has perceived the sublime object there displayed. After returning home, that object frequently comes up to his mind afresh. While standing upon the banks of the river and looking upon the cataract, he had a perception of it; the recurrence of that object to his mind after returning home is a conception of it.

The mind first perceives its object before conceiving it; and it never conceives a physical object but in its absence. Perception is the introduction of a stranger; conception the entertaining of an acquaintance. The first looks at a thing; the second takes it up, to hold it before the mind as an object of contemplation.

So of a sensation. It is first experienced, as a present reality; it afterward recurs to the mind, and is, as it were, felt over again; thus the former experience becomes a conception.

CONCEPTION OF SPECULATIVE TRUTHS.

The term conception is also applied, in popular language, to abstract and metaphysical truths. It is thus used with the same latitude assigned to perception. Dugald Stewart says, "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 speculative truths; and yet an author would be justly censured who should treat of these two operations of the mind under the same article of perception. I apprehend there is as wide a difference between the conception of a truth and the conception of an absent object of sense as between the perception of a tree and the perception of a mathematical theorem."

There is, undoubtedly, the same difference in the one case as in the other; the instances are exactly parallel. In the one case it is an intuitive conception, in the other an intuitive perception. The perceptive and conceptive mental acts sustain to each other the same relation, whether applied to internal or external objects.

FURTHER APPLICATION OF THE TERM.

Conception is also applied to the mental act by which we form a notion of objects described, or in any way represented. A history, a drama, a play, furnishes materials of perception, from which the mind conceives the objects. represented. It is evident, that in all these cases the mental act of conceiving is essentially one and the same.

DISTINCTION BETWEEN CONCEPTION AND MEMORY.

At first view, conception may seem to be the same as memory. But, on examination, it will appear that they differ in essential particulars. They do certain things in common, but each has also its peculiar offices.