Time is insignificant and never a difficulty for Nature. It is always at her disposal.
What nature does in the course of long periods we do every day when we suddenly change the environment in which some species of living plant is situated.
It is not the organs—that is, the character and form of the animal’s bodily parts—that have given rise to its habits and particular structures. It is the habits and manner of life and the conditions in which its ancestors lived that have in the course of time fashioned its bodily form, its organs and qualities.
All knowledge that is not the real product of observation, or of consequences deduced from observation, is entirely groundless and illusory.