The fatal man, is he not always the unthinking man, the man who cannot think and see
 Thomas Carlyle, On Heroes, Hero-Worship, and The Heroic in History (1841). copy citation

Context

“Very notable;—and worth mentioning, though we know what is to be said and answered! As if Thought, Power of Thinking, were not, at all times, in all places and situations of the world, precisely the thing that was wanted. The fatal man, is he not always the unthinking man, the man who cannot think and see; but only grope, and hallucinate, and missee the nature of the thing he works with? He mis-sees it, mistakes it as we say; takes it for one thing, and it is another thing,—and leaves him standing like a Futility there!” source