Pleasure in itself is not bad but good: contrariwise, pain in itself is bad.
 Baruch Spinoza, Ethics (1677). copy citation

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Author Baruch Spinoza
Source Ethics
Topic pain pleasure
Date 1677
Language English
Reference
Note Translated by R. H. M. Elwes
Weblink http://www.gutenberg.org/files/3800/3800-h/3800-h.htm

Context

“Proof.—For whatsoever causes men to live together in harmony also causes them to live according to reason (IV. xxxv.) , and is therefore (IV. xxvi. xxvii.) good, and (for the same reason) whatsoever brings about discord is bad. Q.E.D. PROP. XLI. Pleasure in itself is not bad but good: contrariwise, pain in itself is bad. Proof.—Pleasure (III. xi. and note) is emotion, whereby the body's power of activity is increased or helped; pain is emotion, whereby the body's power of activity is diminished or checked; therefore” source