Submission + - I'm Thinking. Please. Be Quiet. (nytimes.com)
His argument against noise was simple: A great mind can have great thoughts only if all its powers of concentration are brought to bear on one subject, in the same way that a concave mirror focuses light on one point. Just as a mighty army becomes useless if its soldiers are scattered helter-skelter, a great mind becomes ordinary the moment its energies are dispersed.
And nothing disrupts thought the way noise does, Schopenhauer declared, adding that even people who are not philosophers lose whatever ideas their brains can carry in consequence of brutish jolts of sound.