pression in the mind, I reply that this is not consistent with the revelation of consciousness, which announces plainly that what we know is something extra-mental. If they say, with Kant, a mere phenomenon in the sense of appearance, then I reply that this too is inconsistent with consciousness, which declares that we know the thing. But if we know the thing, we must know something about it. If they say we know it as having extension and form, I grasp at the admission, and ask them to consider how high the knowledge thus allowed, involving at one and the same time space, and an object occupying space, and so much of space. Surely those who acknowledge this much may be prepared to confess further that the mind which in perception is capable of knowing an object as occupying space, is also capable of knowing the same object as exercising power in regard to us. We have only to examine the state of mind involved in all our cognitions of matter to discover that there is involved. in it a knowledge both of extension and power.

(a) The following is the account given by Müller (Physiology, trans. by Baly, p. 1080): "First, the child governs the movement of its limbs, and thus perceives that they are instruments subject to the use and government of its internal 'self,' while the resistance which it meets with around is not subject to its will, and therefore gives it the idea of an absolute exterior. Secondly, the child will perceive a difference in the sensations produced according as two parts of its own body touch each other, or as one part of its body only meets with resistance from without. In the first instance, where one arm, for example, touches the other, the resistance is offered by a part of the child's own body, and the limb thus giving the resistance becomes the subject of sensation as well as the other. The two limbs are in this case external objects of perception, and percipient at the same time. In the second instance, the resisting body will be represented to the mind as something external and foreign to the living body, and not subject to the internal 'self.' Thus will arise in the mind of the child the idea of a resistance which one part of its own body can offer to other parts of its body,

and at the same time the idea of a resistance offered to its body by an absolute 'exterior.' In this way is gained the idea of an external world as the cause of sensations."

(b) The Cheselden case is reported in Phil. Trans. 1728. I have noticed other cases in my Psychology, The Cognitive Powers, B. 1. C. i. 11. Berkeley, Stewart, and Brown hold that color without extension is the proper object of sight. Hamilton (Metaphysics, Lect. 27) seems to me to demonstrate that a perception of colors, and consequently of the difference of colors, necessarily involves the perception of a discriminating line, and that a line and figure are modifications of extension, so that "a perception of extension is necessarily given in the perception of colors."

(c) If the eye gives lines and figures, it must in a sense give the distance (of course not the measured distance) of one point or edge of a figure from another. This is a necessary modification of the Berkeleyan theory of vision. What the persons whose eyes were couched felt as touching their eyes must have been felt as a surface like their skin. Though they had no intuitive means of determining the distance of the seen surface from their felt and localized organism, yet it should be observed, they have extension in the original ocular perception, and a preparation for measuring the distance of the seen surface with the aid of the muscular sense, more particularly as the hand moves over the seen object or moves from one seen object to another. In reference to a cognate question, there can be no doubt, I think, that persons with a newly imparted power of vision would by binocular vision see a solid as different from a surface, but it does not follow that they would know it to be a solid.

(d) The convictions referred to in these paragraphs set aside at once the doctrine of Kant, that the mind, in the intuition of sense, takes cognizance of phenomena in the sense of appearances. They should also modify the doctrine of Hamilton. "Our knowledge of qualities or phenomena is necessarily relative, for these exist only as they exist in relation to our faculties " (foot-note to Reid, p. 323). It is a truism that we can know objects merely as our faculties enable us to know them; but the question is, What is the nature and extent of the knowledge which our faculties furnish? I admit that whatever external objects we know, we know in a relation to us. But I hold that man and his faculties are so constituted as to know things (with being) exercising qualities, and to know qualities as existing separate from and independent of our cognition of them by our faculties.

(e) The convictions spoken of in these paragraphs set aside all

forms of idealism in sense-perception. Berkeley says that "of unthinking things without us their esse is percipi, nor is it possible they should have any existence out of the minds of thinking things which perceive them." "When we do our utmost to conceive the existence of external bodies, we are all the while only contemplating our own ideas" (Principles of Human Knowledge, ii. xxiv.). I hold, that according to our intuitive conviction, the thing which we perceive must exist before we can perceive it, and that we perceive it as an extended thing independent and out of the contemplative mind. Fichte represents the external thing as a creation or projection of the perceiving mind. But the mind, in knowing the self as perceiving, knows that it is an external thing that is perceived, and cannot be made to think otherwise. Professor Ferrier bases his fabric of demonstrated idealism on the proposition, the object of knowledge "always is, and must be, the object with the addition of one's self, object plus subject, thing, or thought, mecum (Inst. of Metaph. Prop. ii.). If this proposition professes to be a statement of fact, I deny that the fact of consciousness is properly stated. If it professes to be a first truth, I deny that it ought to be assumed in this particular form. No doubt we always know self at the same time that we know an external object by sense-perception, but we know the external object as separate from and independent of self. We might as well deny that we know the object at all as deny that we know it to have an existence distinct from self.

(f) Hamilton says, "An extension is apprehended in the apprehension of the reciprocal externality of all sensations" (Appendix to Reid, p. 885). Again, "In the consciousness of sensations relatively localized and reciprocally external, we have a veritable apprehension and consequently an immediate perception of the affected organism, as extended, divided, figured," etc. (Ibid. p. 884). Em. Saisset, in the article Sens, in Dict. des Sciences Philosophiques, dwells on the localization of our sensations in their various organic seats.

(9) Locke says that impenetrability, or, as he prefers calling it, as having less of a negative meaning, solidity, seems the "idea most intimately connected with and essential to body, so as nowhere else to be found or imagined, but only in matter;" and he adds, we "find it inseparably inherent in body wherever or however modified;" and in explaining this, be says of bodies that "they do by an insurmountable force hinder the approach of the parts of our hands that press them" (Essay, II. IV. 1). Herbert Spencer has done great service to philosophy by showing that force is implied in all knowledge by the senses.

CHAPTER III.

DISTINCTIONS TO BE ATTENDED TO IN OUR COGNITION OF BODY..

It is maintained in this work that all we know by the senses is real. But we must be careful to determine what we do thus know. In order to defend the doctrine of Realism we must draw several important distinctions.

I.

The difference between Extra Mental and Extra Organic perception. All objects perceived are beyond the mind, but all are not beyond the body. Probably our first perceptions, mingled with sensations, are of our bodily frame; for anything we know, there may be tactile perceptions by the infant in the womb. It is certain that in our mature life we have organic affections, such as those of the alimentary canal and stomach, which exercise no action without the body. We must take care not to give the organic affections an extra organic validity.

II.

The distinction between Sensation and Perception. Perception is the knowledge of the object presenting itself to the senses, whether in the object or beyond it. Sensation is the feeling associated, the feeling of the organism. These two always coexist. There is never this knowledge without an organic feeling; never a feeling of the organism without a cognitive apprehen

sion of it.1 These sensations differ widely from each other, as our consciousness testifies; some of them being pleasant, some painful; others indifferent as to pleasure and pain, but still with a feeling. Some we call exciting, others dull; some we designate as warm, others as cold; and for most of them we have no name whatever, — indeed they so run into each other that it would be difficult to discriminate them by a specific nomenclature. The perceptions, again, are as numerous and varied as the knowledge we have by all the senses. Now these two always mix themselves up with each other. The sensation of the odor mingles with the apprehension of the nostrils; the flavor of the food is joined with the recognition of the palate; the agreeableness or disagreeableness of the sound comes in with the knowledge of the ear as affected; and the feeling organ which we localize has an associated sensation. There is an organic sensation conjoined even with the knowledge we have of the extra-organic object affecting our muscular sense, or our visual organism. This sensation may be little noticed because the attention is fixed on the object; still, it is always there, as we may discover by a careful introspection of the combined mental affection. But while the two ever coexist, sometimes with the one prevailing, and sometimes with the other predominant, and sometimes with the two nicely balanced, it is of importance to distinguish them. Every man of sense draws the distinction between the music and the musical instrument, between the ear-ache and

1 Reid represents the sensation as being "followed by a perception of the object;" on which Hamilton remarks," that sensation proper precedes perception proper is a false assumption; they are simultaneous elements of the same invisible energy" (Reid's Collected Writings, p. 186. See, also, p. 853).