CHAPTER II.

CRITICISM OF THE SENSATIONAL THEORY.

$1. Sensation as sense-perception.-This view, as stated by Locke, represents the mind, in sensation, as passive to the impress of extended objects, and the consciousness of the impression thus received, as the perception of such objects. If the mind were, in strictness, merely receptive of such impressions, it would require an actual impact of physical forces, and a corresponding impress of extended objects upon the non-extended mind. Had this fact been evident to Locke, he doubtless would have amended his theory. Three reasons may be pointed out for his failure to recognize it. First, when he represents the mind as passive, he does not conceive it as entirely passive. As has been shown, activity and passivity are strict correlates; and when either term is used, it is used in a sense not absolute but relative. Again, in tactual perception, the tactual surface receives an actual impress of extended objects, and this impress gives rise to a metaphor in which such perception is represented as an impression upon the mind. Lastly, in visual perception, the impress is refined into the convergence of rays of light upon a focal point which, losing nearly all extension, easily cheats one, who has taken the metaphor in a literal sense, into believing that an actual impression has been made upon the mind. In order to correct Locke's error, it is only necessary to realize that the human mind is necessarily both active and passive in every conscious state, that the phrase, "impression on the mind," is always necessarily metaphorical, that a non-extended mind cannot be located in any point of space, and that nothing can receive an impact of physical forces un

less it be both extended and material. Locke deserves great credit for distinguishing between sensation and reflection; but not only is his distinction untenable, his method of reasoning also must be abandoned.

Berkeley improved upon Locke's account by making the mind active in sensation; but his failure to make any distinction between sense and intellect led not only to an exaggerated form of sensationalism, but also to sensational idealism, both of which have been very generally rejected.

Hume's great service consisted in establishing the fact that no knowledge of universal validity can come from sensations alone; but the answer to the scepticism thus awakened was reserved for Kant.

$2. Sensations as subjective percepts.-Thomas Reid, in his distinction between sensation and perception, makes a decided advance toward the true nature of the difference between them. His treatment consisted in the abstraction of the category of causality from the process of perception, and the identification of the perceptive process, as so modified, with sensation. If this distinction were made complete, by abstracting from perception all a priori categories, the distinction would be identical with the correlative theory. But stopping where Reid does only gives one of the various points of contrast between sense and intellect, and implies that this is all the distinction there is to be made. It is true, as Reid infers, that the category of causality characterizes perception and not sensation; but this category can be separated from the process of perception only by abstraction, and then consistency would require the abstraction of all the other a priori categories. To ascribe to sensation any power of perception at all, even if only of subjective affections, as Reid does, is to grant it the category of causality as well as the other categories. If his distinction be of any value, it must lie in the subjective nature ascribed to the object perceived in sensation. This point is emphasized by Hamilton.

Hamilton, while criticising Reid's form of statement, holds to the same distinction between sensation and per

ception.

In making "the modern distinction of the Primary and Secondary Qualities of matter" correspond to the "modern distinction of the two perceptions, Perception proper and Sensation proper," he simply extends Reid's distinction to all objects of sense, and makes the distinction a little stronger by abstracting more of the a priori categories. But since these categories can be separated from the perceptive process only by abstraction, the process so modified would correspond to nothing found in actual experience. Yet Hamilton has in mind cases of perception in actual experience, and identifies sensation with such cases. His distinction must, therefore, if maintained, rest entirely upon the subjective character assigned to the objects perceived in sensation. His "material Non-ego" clearly implies a correlative material ego as the real basis of his "organic passion," and clearly shows that his "subject-object" is actually objectified in causal relations. As Dr. Ward says, "When considerations of method compel us to eliminate physiological implications from the ordinary conception of a sensation, we are able to distinguish the conscious subject and the affections of which it is conscious as clearly as we can distinguish subject and object in other cases of presentation." The "ordinary conception," to which Dr. Ward referred, was Hamilton's. The only distinction that Hamilton can be said to have made would be, not a "distinction of the Primary and Secondary Qualities of matter," as he supposed, since his "subject-object" retains "Primary" as well as "Secondary Qualities," but a distinction between incipient and advanced stages of perception, between stages in which the objective relations of the percepts are vague and stages in which they are clear. This distinction reduces to the third form of this theory, which will be criticised in order; but that Hamilton did not have this distinction in mind is shown by the following quotation: "On the testimony of consciousness, and in the doctrine of intuitive perception, the mind, when a material existence is brought into relation with its organ of sense, obtains two concomitant, and immediate cogni

1 Ency. Brit. Vol. XX, p. 41.

tions. Of these, the one is the consciousness (sensation) of certain subjective modifications in us, which we refer, as affections, to certain unknown powers, as causes, in the external reality; the secondary qualities of body: the other is the consciousness (perception) of certain objective attributes in the external reality itself, as, or as in relation to our sensible organism; the primary qualities of body. Of these cognitions, the former is admitted, on all hands, to be subjective and ideal; the latter, the Natural Realist maintains, against the Cosmothetic Idealist, to be objective and real." This statement of Hamilton's, that in sense-perception the mind "obtains two concomitant and immediate cognitions," one subjective and the other objective, is an exaggerated distortion of the perceptive process in which two correlative aspects of one process are represented as two separate processes. It is impossible to divide sense-percepts into two classes, subject-objects and object-objects. An attempt to do so soon shows that every sense-percept necessarily has both aspects, the subjective and the objective, and that the two aspects are strictly correlative. The only conclusion possible is that Reid and Hamilton tried to make a distinction between sensation and perception on an untenable basis.

J. S. Mill's doctrine of sensation, when carried to its logical results, reduces both primary and secondary qualities of matter to a sensational basis, and thus reverts to Locke's sensational realism. It reduces all objects of perception to "permanent possibilities of sensation," that is, to permanent possibilities of signs of permanent possibilities, &c., ad infinitum. It also reduces sensations to signs of "permanent possibilities of sensation," that is, to signs of permanent possibilities of signs, &c., ad infinitum. It is hardly necessary to state that the view is untenable, yet, in a less explicit form of statement, it is still held very generally.

In criticising Lotze's doctrine of sensation, it is necessary first to note the different constructions that can be logically put upon his statements, for they are certainly

1 O. W. Wight's "Philosophy of Sir William Hamilton," p. 274.

susceptible of more than one. If his "impressions," which "exist conjointly in the soul although not spatially side by side with one another," and which the soul apprehends "not in the form in which they actually are-to-wit, nonspatial-but as they are not, in a spatial juxtaposition,”— if these impressions are the elements actually entering into and forming objects of perception; then his doctrine is a form of sensational idealism. But if, as a natural realist, Lotze makes sensations mere signs of permanent objects, each sign having an "accessory impression" for a "local sign" to determine what part of the permanent object each primary impression is to signify, then his doctrine reduces to a sensational realism still more refined than J. S. Mill's. Lotze cannot be classed with "psychic stimulists," since he believes the impressions to "exist conjointly in the soul," and to be apprehended, not directly as they are produced, but by reproduction; not as "they actually are," "but as they are not, in a spatial juxtaposition." His position seems to be anomalous. He postulates sensations after the analogy of J. S. Mill's signs, but he is not, like Mill, a natural realist. He seems to be a sensational idealist, holding objects of perception to be constructed, not upon the occurrence of sensations as stimuli to intellectual activity, but out of sensations. He is not of the same view as Berkeley, who made no distinction between sense and intellect; for Lotze distinguishes between the impressions and the power of the soul to act on them, and represents the impressions as passive to such action. His objects of perception are intellectual constructions, but into them the impressions enter as component factors. This form of idealism, as well as Berkeley's, is devoid of all a priori validity, since the constructions are determined, not by intellectual relations, but by sensations called "accessory impressions" which serve as "local signs." This doctrine would also make sensations fixed entities, like objects of perception, which is contrary to all other theories of sensation. Lotze's position, under all possible interpretations, is untenable.

J. Clark Murray confesses that a simple sensation