Pleasure is caused by good, which has only one meaning
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic pleasure good
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17897/pg17897-images.html

Context

“And the reason why torpor especially is said to deprive one of speech is because of all the external movements the voice is the best expression of the inward thought and desire, not only in men, but also in other animals, as is stated in Polit. i, 1. Reply Obj. 1: Pleasure is caused by good, which has only one meaning: and so pleasure is not divided into several species as sorrow is; for the latter is caused by evil, which "happens in many ways," as Dionysius says (Div. Nom. iv) . Reply Obj. 2: Repentance is for one's own evil, which is the proper object of sorrow:” source