Men do not fail commonly for want of knowledge, but for want of prudence to give wisdom the preference.
 Henry David Thoreau, A Week on the Concord and Merrimack Rivers (1849). copy citation

Context

“The nonchalance and dolce-far-niente air of nature and society hint at infinite periods in the progress of mankind. The States have leisure to laugh from Maine to Texas at some newspaper joke, and New England shakes at the double-entendres of Australian circles, while the poor reformer cannot get a hearing. Men do not fail commonly for want of knowledge, but for want of prudence to give wisdom the preference. What we need to know in any case is very simple. It is but too easy to establish another durable and harmonious routine. Immediately all parts of nature consent to it. Only make something to take the place of something, and men will behave as if it was the very thing they wanted.” source