Vision and Reality

Abstract

IF a philosopher may be permitted to take part in a discussion which seems to involve questions of scientific import alone, I would like to point out certain ideas which bear upon the problem of whether the eye has been so adapted as best to use the energy of sunlight. Sir John Parsons suggests (NATURE, Jan. 21, p. 94) that this conclusion is consistent with the fact that the brightest part of the spectrum (of the luminosity curve) coincides with the summit of the curve of radiant energy. But Mr. T. Smith (NATURE, Feb. 18, p. 242) presents another view—not inconsistent with the foregoing conception—in which vision is held to be so constituted as to bring out the sharpness of contours of bodies. This conclusion, while very important, does not seem to me to be especially novel. Prof. Eddington, in his “Stars and Atoms,” also suggested that we have in the coincidence of the peak of the visibility curve with the peak of the curve of radiant energy an interesting case of evolutionary adaptation. But aside from these views, Bergson, it might be argued, hadproposed something of the sort in his notion of the ‘geometrising intellect.’ This, at any rate, would be the case if the interpretation which the present writer puts on Bergson is the true one.