It is a significant fact that in order to appreciate the peculiar place of habit in activity we have to betake ourselves to bad habits, foolish idling, gambling, addiction to liquor and drugs. When we think of such habits, the union of habit with desire and with propulsive power is forced upon us. When we think of habits in terms of walking, playing a musical instrument, typewriting, we are much given to thinking of habits as technical abilities existing apart from our likings and as lacking in urgent impulsion. We think of them as passive tools waiting to be called into action from without. A bad habit suggests an inherent tendency to action and also a hold, command over us. It makes us do things we are ashamed of, things which we tell ourselves we prefer not to do. It overrides our formal resolutions, our conscious decisions. When we are honest with ourselves we acknowledge that a habit has this power because it is so intimately a part of ourselves. It has a hold upon us because we are the habit.
~John Dewey, Human Nature and Conduct
For what it’s worth, this quote is relevant to recent debates over Jason Stanley’s defense of intellectualism. Dewey would say Stanley’s arguments apply only to “technical” aspects of skill; the “propulsive power” at the heart of habits is surely not “intellectual” at its core.
Minds and Brains 