[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.