Full Idea
Whatever becomes conscious becomes by the same token shallow, thin, relatively stupid, general, sign, herd signal; all becoming conscious involves a great and thorough corruption, falsification, reduction to superficialities, and generalisation.
Gist of Idea
Whatever moves into consciousness becomes thereby much more superficial
Source
Friedrich Nietzsche (The Gay (Joyful) Science [1882], §354)
Book Reference
Nietzsche,Friedrich: 'The Gay Science', ed/tr. Kaufmann,Walter [Vintage 1974], p.299
A Reaction
Nietzsche would have made a great speech writer for someone. This vision is increasingly how I see people. It is a view reinforced by modern neuroscience, which suggests that we greatly overestimate the conscious part of ourselves.