indeed in their various ways valid, indicate a problem rather than define its precise limits.
More to the point, at this stage of our inquiry, than a formally precise definition of Nature, is a consideration of the motives which lead us to acknowledge as real the facts that we all call physical, — viz. to acknowledge the existence of matter, the laws of natural processes, and the dependence of our own mental life upon these processes. To this aspect of the problem of Nature we accordingly at once proceed.
After all that we have now seen regarding the nature of human knowledge, it would be vain to assert that we perceive directly, through our senses, the existence of that which we call matter. The senses never show us, by themselves, the true Being of anything whatever. All truth is the object of acknowledgment, and not merely of immediate experience. Moreover, what has Being is, in itself, something Individual. And the senses never show us individuality, but only the presence of sense-qualities, — colors, sounds, odors, touch, impressions, and the like. On the other hand it is perfectly indubitable that the senses show, now to one and now to another of us men, all the data that, after comparing our various human experiences, we interpret as the signs of the existence of matter. The question is, however, this: In what way do we come by this interpretation?
We cannot say, at this point, that some innate conviction, some first and fundamental axiom, or some opaque “law” of the intellect mysteriously requires us to believe that matter is real. This we cannot now assert, just because our Idealism knows nothing what-
