Nature is as well adapted to our weakness as to our strength. The incessant anxiety and strain of some is a well-nigh incurable form of disease. We are made to exaggerate the importance of what work we do; and yet how much is not done by us! or, what if we had been taken sick? How viligant we are! determined not to live by faith if we can avoid it; all the day long on the alert, at night we unwillingly say our prayers and commit ourselves to uncertainties. So thoroughly and sincerely are we compelled to live, reverencing our life, and denying the possibility of change. This is the only way, we say; but there are as many ways as there can be drawn radii from one centre. All change is a miracle to contemplate; but it is a miracle which is taking place every instant. Confucius said, “To know that we know what we know, and that we do not know what we do not know, that is true knowledge.” When one man has reduced a fact of the imagination to be a fact of his understanding, I forsee that all men will at length establish their lives on that basis.
Walden – Henry David Thoreau
From the chapter titled “Economy”