Full Idea
The principium individuationis, 'tis plain, is existence itself, which determines a being of any sort to a particular time and place incommunicable to two beings of the same kind.
Clarification
The 'principium individuationis' (Latin) is the principle of individuation
Gist of Idea
A thing is individuated just by existing at a time and place
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.27.03)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.330
A Reaction
I wish I could get completely clear about what a 'principle of individuation' is supposed to do. E.J. Lowe is always banging on about them. I would have thought that being an individual had to precede any 'principle' underlying it.
Related Idea
Idea 13098 We use things to distinguish places and times, not vice versa [Leibniz]