[119]. This definition of the physical order approximates very closely to that adopted by Prof. Münsterberg in his Grundzüge der Psychologie, vol. i. pp. 65-77. Prof. Münsterberg defines a physical fact as one which is directly accessible to the perception of a plurality of sentient individuals, as opposed to the psychical fact which can be directly experienced only by one individual. It must be remembered, of course, that my body as directly experienced in “common sensation” and “emotional mood” belongs to the psychical order. It is only my body as perceptible by other men that is a member of the physical order.
[120]. Cf. Bradley, Appearance and Reality, chap. 22, pp. 260-267 (1st ed.). The attempts which have been made to exempt “primary” qualities from this relativity do not seem to demand serious criticism. The argument in the text applies as directly to extension and shape as to colour or smell. It is not defensible to contend, as Mr. Hobhouse does, that qualities, whether primary or secondary, depend on the percipient organ only for their perception, not for their existence. The contention rests upon taking two aspects of experience which are always given together, the that and the what of a sense-content, and arguing that because these two aspects of a single whole can be distinguished, therefore the one can exist in actual separation from the other. It would be quite as logical to infer by the same method and from the same premisses that there can be a perceptive state without any content, as that the contents can exist as we know them, apart from the state.
[121]. See particularly the detailed statement of his contention and the elaborate examination of objections in the Three Dialogues between Hylas and Philonous, which form a commentary on the briefer exposition of Principles of Human Knowledge, §§ 1-134.
[122]. See the fuller exposition of this line of argument in Royce, Studies in Good and Evil, essay on “Nature, Consciousness and Self-Consciousness,” to which I am largely indebted throughout the present chapter, and for a detailed criticism of the alleged “analogical” inference the closely related reasoning of my own essay on “Mind and Nature” in International Journal of Ethics, October 1902. The similar but briefer criticism in Royce, The World and the Individual, Second Series, lecture 4, “Physical and Social Reality,” p. 170, I had not had the opportunity to study when the above was written. For the whole subject of imitation, see in particular Professor Baldwin’s Mental Development in the Child and the Race.
[123]. For a study of the significance of the “partial independence” of the physical world on my will as a factor in producing belief in its “external reality,” see Stout, Manual of Psychology,3 bk. iii. pt. 2, chaps. 1-2, “The Perception of External Reality.”
[124]. The doctrine of degrees of reality must be borne in mind throughout this discussion. The reality of which the physical order is phenomenal may itself be phenomenal of a higher reality.
[125]. Societies would be the more natural supposition. We have no reason to deny that the various types of non-human intelligence may be cut off from social intercourse with each other, as they are from intercourse with ourselves.
[126]. That is, there are degrees of truth as well as of reality, and the two do not necessarily coincide. The degree of truth a doctrine contains cannot be determined apart from consideration of the purpose it is meant to fulfil. For the special purposes of Metaphysics, the purpose of thinking of the world in a finally consistent way, whatever is not the whole truth is untrue. But what the metaphysician regards as the lesser truth may be the higher truth relatively to other purposes than his own. Compare the doctrine of Dr. Stout’s essay on “Error” in Personal Idealism.