tion? And then, as we have also shown,[1] how could a surface be perceived as a surface otherwise than in a space that has recovered its three dimensions? Berkeley, at least, carried out his theory to its conclusion; he denied to sight any perception of extensity. But the objections which we raised only acquire the more force from this, since it is impossible to understand the spontaneous creation, by a mere association of memories, of all that is original in our visual perceptions of line, surface and volume, perceptions so distinct that the mathematician does not go beyond them and works with a space that is purely visual. But we will not insist on these various points, nor on the disputable arguments drawn from the observation of those, born blind, whose sight has been surgically restored: the theory of the acquired perceptions of sight, classical since Berkeley's day, does not seem likely to resist the multiplied attacks of contemporary psychology.[2] Passing over the difficulties of a psychological order, we will content ourselves with drawing attention to another point, in our opinion essential. Suppose for a moment that
- ↑ Time and Free Will. Sommenschein & Co., 1910.
- ↑ See on this subject: Paul Janet, La perception visuelle de la distance, Revue philosophique, 1879, vol. vii, p. 1 et seq.—William James, Principles of Psychology, vol. ii, chap. xxii.—Cf. on the subject of the visual perception of extensity: Dunan, L'espace visuel et l'espace tactile (Revue philosophique, Feb. and Apr. 1888, Jan. 1889).
