In his Experiment in Autobiography (1934), H. G. Wells pointed out that ever since the beginning of life, most creatures have been 'up against it'. Their lives are a drama of struggle against the forces of nature. Yet nowadays you can say to a man: Yes, you earn a living, you support a family, you love and hate, but -- what do you do? His real interest may be in something else -- art, science, literature, philosophy. The bird is a creature of the air, the fish is a creature of the water, and man is a creature of the mind.