Note 34 — Chapter IV

Wundt (Physiologische Psychologie, p. 653) would exclude from illusions all those errors of sense-perception which have their foundation in the normal structure and function of the organs of sense. Thus, he would exclude the effects of colour-contrast, e.g. the apparent modification of two colours in, juxtaposition towards their common boundary, which probably arises (according to E. Hering) from some mutual influence of the temporary state of activity of adjacent retinal elements. To me, however, these appear to be illusions, since they may be brought under the head of wrong interpretations of sense-impressions. When we see a grey patch as rose-red, as though it were so independently of the action of the complementary light previously or simultaneously, that is to say, as though it would appear rose-red to an eye independently of this action, we surely misinterpret.