…no sooner have we drawn a conclusion, than we begin to turn upon it with a critic’s eye, and to ask whether it really conformed to our logical ideals. Indeed, unless we do this, in the proper use of language the operation ought not to be called reasoning; for reasoning properly means controlled thought, and the only possible control consists in critical review, or self-confession.
http://www.commens.org/dictionary/entry/quote-lecture-i-r-3