Page:Conservationofen00stew.djvu/243

 the less is left to the other. Such is the statement of the correlation of mind to the other forces of Nature. We do not deal with pure mind—mind in the abstract; we have no experience of an entity of that description. We deal with a compound or two-sided phenomenon—mental on one side, physical on the other; there is a definite correspondence in degree, although a difference of nature, between the two sides; and the physical side is itself in full correlation with the recognized physical forces of the world.

II. There remains another application of the doctrine, perhaps equally interesting to contemplate, and more within my special line of study. I mean the correlation of the mental forces among themselves (still viewed in the conjoint arrangement). Just as we assign limits to mind as a whole, by a reference to the grant of physical expenditure, in oxidation, etc., for the department, so we must assign limits to the different phases or modes of mental work—thought, feeling, and so on—according to the share allotted to each; so that, while the mind as a whole may be stinted by the demands of the non-mental functions, each separate manifestation is bounded by the requirements of the others. This is an inevitable consequence of the general principle, and equally receives the confirmation of experience. There is the same absence of numerical precision of estimate; our scale of quantity can have but few divisions