A passion is an original existence, or, if you will, modification of existence, and contains not any representative quality, which renders it a copy of any other existence or modification.
 David Hume, A Treatise of Human Nature (1738). copy citation

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

Context

“Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them. As this opinion may appear somewhat extraordinary, it may not be improper to confirm it by some other considerations.
A passion is an original existence, or, if you will, modification of existence, and contains not any representative quality, which renders it a copy of any other existence or modification. When I am angry, I am actually possest with the passion, and in that emotion have no more a reference to any other object, than when I am thirsty, or sick, or more than five foot high. It is impossible, therefore, that this passion can be opposed by, or be contradictory to truth and reason; since this contradiction consists in the disagreement of ideas, considered as copies, with those objects, which they represent.
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