The reason why he left Walden shows one of his pronounced transcendental characteristics, a dread of repetition. He gives an account of only his first year of life there, and adds, "the second year was similar to it." He says:-- "I left the woods for as good a reason as I went there. Perhaps it seemed to me that I had several more lives to live, and could not spare any more time for that one. It is remarkable how easily and insensibly we fall into a particular route, and make a beaten track for ourselves. I had not lived there a week before my feet wore a path from my door to the pond side." He does not demand that other human beings shall imitate him in devoting their lives to a study of nature. He says, "Follow your genius closely enough, and it will not fail to show you a fresh prospect every hour." He thus expresses his conception of the fundamental basis of happiness in any of the chosen avenues of life:-- "Our whole life is startlingly moral. There is never an instant's truce between virtue and vice. Goodness is the only investment that never fails." His insistence on the necessity of a moral basis for a happy life is a characteristic that he shared in common with the great authors of the New England group, but he had his own individual way of impressing this truth. He thought life too earnest a quest to tolerate the frivolous or the dilettante, and he issued his famous warning that no one can "kill time without injuring eternity." His aim in studying nature was not so much scientific discovery as the revelation of nature's joyous moral message to the spiritual life of man. He may have been unable to distinguish between the song of the wood thrush and the hermit thrush. To him the most important fact was that the thrush is a rare poet, singing of "the immortal wealth and vigor that is in the forest." "The thrush sings," says Thoreau, in his _Journal_, "to make men take higher and truer views of things." The sterling honesty and directness of Thoreau's character are reflected in his style. He says, "The one great rule of composition--and if I were a professor of rhetoric I should insist on this--is to _speak the truth_." This was his aim in presenting the results of the experience of his soul, as well as of his senses. If he exaggerated the importance of a certain way of regarding things, he did so only because he thought the exaggeration was necessary to secure attention for that particular truth, which would even then not be apprehended at its full value. His style has a peculiar flavor, difficult to describe. Lowell's characterization of Thoreau's style has hardly been surpassed. "His range was narrow, but to be a master is to be a master. There are sentences of his as perfect as anything in the language, and thoughts as clearly crystallized; his metaphors and images are always fresh from the soil."