Full Idea
In that proposition 'an object is the same with itself', if the idea expressed by the word 'object' were no way distinguished from that meant by 'itself', we should really mean nothing. ...One single object conveys the idea of unity, not that of identity.
Gist of Idea
'An object is the same with itself' is meaningless; it expresses unity, not identity
Source
David Hume (Treatise of Human Nature [1739], I.IV.2)
Book Reference
Hume,David: 'A Treatise of Human Nature', ed/tr. Selby-Bigge/Nidditch [OUP 1978], p.200
A Reaction
As far as I can see it is mathematicians who like self-identity, to justify x=x, which they need. To say 'this vase is identical with itself' is an empty locution. It expresses either unity or stability over time. See Idea 21292.
Related Idea
Idea 21292 Saying an object is the same with itself is only meaningful over a period of time [Hume]