Men will scarce ever be persuaded, that effects of such consequence can flow from principles, which are seemingly so inconsiderable, and that the far greatest part of our reasonings with all our actions and passions, can be derived from nothing but custom and habit.
 David Hume, A Treatise of Human Nature (1738). copy citation

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Author David Hume
Source A Treatise of Human Nature
Topic action custom
Date 1738
Language English
Reference
Note
Weblink http://www.gutenberg.org/files/4705/4705-h/4705-h.htm

Context

“This perhaps will be the fate of what I have here advanced concerning belief, and though the proofs I have produced appear to me perfectly conclusive, I expect not to make many proselytes to my opinion. Men will scarce ever be persuaded, that effects of such consequence can flow from principles, which are seemingly so inconsiderable, and that the far greatest part of our reasonings with all our actions and passions, can be derived from nothing but custom and habit. To obviate this objection, I shall here anticipate a little what would more properly fall under our consideration afterwards, when we come to treat of the passions and the sense of beauty. There is implanted in the human mind a perception of pain and pleasure, as the chief spring and moving principle of all its actions.” source