I Basic Philosophy
II Necessary Knowledge
III Productive Living
IV Autobiography
V Beauty
VI Art-Making
Appendix I: Picture Library
From: R.L. Gregory, Eye and Brain
Our eyes are general purpose instruments for feeding the brain with comparatively undoctored information, while the eyes of animals possessing simpler brains are more elaborate, for they filter out information which is not essential to their survival or usable by the simple brain. For example, the retina of the frog is capable of signalling only a few characteristics; mainly movement and the presence of corners. A frog will starve to death surrounded by dead flies.