Books on Amazon
Definition property/self-identity/sameness/Millikan: the identity of the properties of an individual is determined by natural opposition to these properties, based on that individual.
Definition Individuals/Self-identity/Sameness/Millikan: the identity of an individual is defined by the fact that it naturally has the qualities it has.
The identity of an individual is determined by the rejection of contradictory properties.
A self-identical individual has exactly one property from each property domain, whereby the property domains are mutually exclusive.
R. G. Millikan
Language, Thought, and Other Biological Categories: New Foundations for Realism Cambridge 1987