Full Idea
Everything that takes place naturally is pleasant.
Clarification
'Nature' is the Greek word 'physis'
Gist of Idea
Everything that takes place naturally is pleasant
Source
Plato (Timaeus [c.362 BCE], 81e)
Book Reference
Plato: 'Timaeus and Critias', ed/tr. Lee,Desmond [Penguin 1971], p.111
A Reaction
Not many people would agree with this. I recently watched a sparrowhawk eat a pigeon in my garden. This is the source of the stoic formula of living according to nature.