Since all things are good, men fail at last to distinguish which is the bane, and which the antidote.
 Henry David Thoreau, A Week on the Concord and Merrimack Rivers (1849). copy citation

Context

“It reminds me of the first chapter of Genesis. But how should they know that it is good? That is the mystery to me. I am always agreeably disappointed; it is incredible that they should have found it out. Since all things are good, men fail at last to distinguish which is the bane, and which the antidote. There are sure to be two prescriptions diametrically opposite. Stuff a cold and starve a cold are but two ways. They are the two practices both always in full blast. Yet you must take advice of the one school as if there was no other.” source