Stage 1 -- Infancy (birth to two years).
We are born capable of sensation and from birth
are affected in diverse ways by the objects around us. As soon as we become
conscious of our sensations, we are inclined to seek or avoid the objects which
produce them . . . These inclinations (to seek or avoid) extend and
strength the growth of sensibility and intelligence, but under the pressure of
habit they are changed to some extent with our opinions. The inclinations
before this change are what I call our nature. In my view everything
ought to be in conformity with these original inclinations. (Emile, Book 1,
1956)