Charles Sanders Peirce Quote

It is terrible to see how a single unclear idea, a single formula without meaning, lurking in a young man's head, will sometimes act like an obstruction … in an artery, hindering the nutrition of the brain, and condemning its victim to pine away in the fullness of his intellectual vigor and in the midst of intellectual plenty.

"How to make our ideas clear, Popular Science Monthly, Vol. 12 (January 1878)