Full Idea
When we drink to quench thirst, we lose the distress of the thirst and the pleasure of drinking at the same moment, but one loss is good and the other bad, so the pleasure and the goodness must be separate.
Gist of Idea
In slaking our thirst the goodness of the action and the pleasure are clearly separate
Source
Plato (Gorgias [c.378 BCE], 497d)
Book Reference
Plato: 'Gorgias', ed/tr. Waterfield,Robin [OUP World's Classics 1994], p.88
A Reaction
This is open to the objection that the good of slaking one's thirst is a long-term pleasure, where the drinking is short-term, so pleasure is still the good.