The Normative Sciences, Esthetics, Ethics, and Logic, […] are confined respectively to ascertaining how Feeling, Conduct, and Thought ought to be controlled supposing them to be subject in a measure, and only in a measure, to self-control, exercised by means of self-criticism, and the purposive formation of habit, as common sense tells us they are in a measure controllable.
http://www.commens.org/dictionary/entry/quote-quest-quest-0