Thoreau writes in his journal:
Some poets have said that writing poetry was for youths only, but not so. In that fervid and excitable season we only get the impulse which is to carry us onward in our future career. Ideals are then exhibited to us distinctly which all our lives after we may aim at but not attain. The mere vision is little compared with the steady corresponding endeavor thitherward. It would be vain for us to be looking ever into promised lands toward which in the meanwhile we were not steadily and earnestly travelling, whether the way led over a mountain-top or through a dusky valley . . .