In summary, there are no small problems. Problems that appear small are large problems that are not understood (p. 17). - Santiago Ramón y Cajal

This history of civilization proves beyond doubt just how sterile the repeated attempts of metaphysics to guess at nature' s laws have been. Instead, there is every reason to believe that when the human intellect ignores reality and concentrates within, it can no longer explain the simplest inner workings of life' s machinery or of the world around us ( p. 2).

Now and then philosophers invade the field of biological sciences with these beguiling generalizations, which tend to be unproductive, purely verbal solutions lacking in substance. At best, they may prove useful when viewed simply as working hypotheses.

Any man could, if he were so inclined, be the sculptor of his own brain ( p. xv).