Full Idea
Where the objects are in their nature changeable and inconstant, we admit of a more sudden transition. The nature of a river consists in the motion and change of parts. What is expected appears of less moment than what is unusual and extraordinary.
Gist of Idea
We accept the identity of a river through change, because it is the river's nature
Source
David Hume (Treatise of Human Nature [1739], I.IV.6)
Book Reference
Hume,David: 'A Treatise of Human Nature', ed/tr. Selby-Bigge/Nidditch [OUP 1978], p.258
A Reaction
Aha! Little does Hume realise how Aristotelian he is! Aristotle may have a more objective view of the 'nature' of a thing, but making inferences about identity over time from a thing's essential nature is pure Aristotle.