"We can think of the evolutionary process that transformed the nonhuman ancestors of mankind into human beings as a succession of small, gradual changes spread over millions of years. But we cannot think of a mind in which the category of action would have been present only in an incomplete form. There is nothing in between a being driven exclusively by instincts and physiological impulses and a being that chooses ends and the means for the attainment of these ends. We cannot think of an acting being that would not in concreto distinguish what is end and what is means, what is success and what is failure, what he likes more and what he likes less, what is his profit or his loss derived from the action and what his costs are."

— Ludwig von Mises, The Ultimate Foundation of Economic Science (PDF)