[48] This conception of "consciousness" as a sort of reduplicate world of things comes to us, I think, chiefly from Hume's conception that the "mind is nothing but a heap, a collection of different perceptions, united together by certain relations."—Treatise of Human Nature, Book I, Part IV, sec. 2. For the evolution of this sort of notion out of the immaterial substance notion, see Bush, "A Factor in the Genesis of Idealism," in the James Festschrift.
[49] See, for example, p. 113. "Thus that which is 'nothing but a state of our consciousness' turns out straightway to be a specifically determined objective fact in a system of facts," and, p. 147, "actual sensation is determined as an event in a world of events."
[50] When it is said that an idea is a "plan of action," it must be remembered that the term "plan of action" is a formal term. It throws no light upon what the action is with respect to which an idea is the plan. It may be chopping down a tree, finding a trail, or conducting a scientific research in mathematics, history, or chemistry.
[51] I owe this idea, both in its historical and in its logical aspects, to my former colleague, Professor Mead, of the University of Chicago.
[52] Studies in Logical Theory, University of Chicago Press, 1903.
[53] Mill's doctrine of the ambiguity of the copula (Logic, Book I, chap. IV, § 1) is an instance of one typical way of evading the problem. After insisting with proper force and clearness upon the objective character of our intellectual beliefs and propositions, viz., that when we say fire causes heat we mean actual phenomena, not our ideas of fire and heat (Book I, chap. II and chap. XI, § 1, and chap. V, § 1), he thinks to dispose of the whole problem of the "is" in judgment by saying that it is only a sign of affirmation (chap. I, § 2, and chap. IV, § 1). Of course it is. But unless the affirmation (the sign of thought) "agrees" or "corresponds with" the relations of the phenomena, what becomes of the doctrine of the objective import of propositions? How otherwise shall we maintain with Mill (and with common-sense and science) the difference between asserting "a fact of external nature" and "a fact in my mental history"?
[54] Studies in Philosophy and Psychology, article by Woodbridge on "The Problem of Consciousness," especially pp. 159-60.
[55] In other words, "ideas" is a term capable of assuming any definition which is logically appropriate—say, meaning. It need not have anything to do with the conception of little subjective entities or psychical stuffs.
[56] Of course, the monistic epistemologies have an advantage in the statement of the problem over the dualistic—they do not state it in terms which presuppose the impossibility of the solution.
[57] This view was originally advanced in the discussion of quite another problem than the one here discussed, viz., the problem of consciousness; and it may not be quite just to dissever it from that context. But as a formula for knowledge it has enough similarity with the one brought out in this paper to suggest further treatment; it is not intended that the results reached here shall apply to the problem of consciousness as such.