Note 390 — Chapter XII

Black round things, square white things, per contra, Nature gives us freely enough. But the combinations which she refuses to realize may exist as distinctly, in the shape of postulates, as those which she gives may exist in the shape of positive images, in our mind. As a matter of fact, she may realize a warm cold thing whenever two points of the skin, so near together as not to be locally distinguished, are touched, the one with a warm, the other with a cold, piece of metal. The warmth and the cold are then often felt as if in the same objective place. Under similar conditions two objects, one sharp and the other blunt, may feel like one sharp blunt thing. The same space may appear of two colors if, by optical artifice, one of the colors is made to appear as if seen through the other.—Whether any two attributes whatever shall be compatible or not, in the sense of appearing or not to occupy the same place and moment, depends simply on de facto peculiarities of natural bodies and of our sense-organs. Logically, anyone combination of qualities is to the full as conceivable as any other, and has as distinct a meaning for thought. What necessitates this remark is the confusion deliberately kept up by certain authors (e.g. Spencer, Psychology, §§ 420-7) between the inconceivable and the not-distinctly-imaginable. How do we know which things we cannot imagine unless by first conceiving them, meaning them and not other things?