Page:Popular Science Monthly Volume 1.djvu/709

Rh career left its imperishable impress on the art it enriched? But who would be bold enough to affirm that an infant Mozart could be born among a tribe whose only musical instrument is a tom-tom, whose only song is a monotonous chant?

Again, by tracing the gradual genesis of some of those ideas which we now accept as "self-evident"—such, for example, as that of the "Uniformity of Nature"—we are able to recognize them as the expressions of certain intellectual tendencies, which have progressively augmented in force in successive generations, and now manifest themselves as mental instincts that penetrate and direct our ordinary course of thought. Such instincts constitute a precious heritage, which has been transmitted to us with ever-increasing value through the long succession of preceding generations; and which it is for us to transmit to those who shall come after us, with all that further increase which our higher culture and wider range of knowledge can impart.

And now, having studied the working action of the human intellect in the scientific interpretation of Nature, we shall examine the general character of its products; and the first of these with which we shall deal is our conception of matter and of its relation to force.

The psychologist of the present day views matter entirely through the light of his own consciousness: his idea of matter in the abstract being that it is a "something" which has a permanent power of exciting sensations, his idea of any "property" of matter being the mental representation of some kind of sensory impression he has received from it; and his idea of any particular kind of matter being the representation of the whole aggregate of the sense-perceptions which its presence has called up in his mind. Thus, when I press my hand against this table, I recognize its unyieldingness through the conjoint medium of my sense of touch, my muscular sense, and my mental sense of effort, to which it will be convenient to give the general designation of the tactile sense; and I attribute to that table a hardness which resists the effort I make to press my hand into its substance, while I also recognize the fact that the force I have employed is not sufficient to move its mass. But I press my hand against a lump of dough, and, finding that its substance yields under my pressure, I call it soft. Or, again, I press my hand against this desk, and I find that, although I do not thereby change its form, I change its place; and so I get the tactile idea of motion. Again, by the impressions received through the same sensorial apparatus, when I lift this book in my hand, I am led to attach to it the notion of weight or ponderosity; and, by lifting different solids of about the same size, I am enabled, by the different degrees of exertion I find myself obliged to make in order to sustain them, to distinguish some of them as light, and others as heavy. Through the medium of another set of sense-perceptions, which some regard as belonging to a different category, we distinguish between bodies that