|Necessity, philosophy: different kinds of necessity are distinguished, differing in their strength. For example, physical, logical or metaphysical necessity. See also necessity de dicto, necessity de re.|
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Nature necessity/necessity/nature/world/reality/Millikan: to the necessities that we find in nature belongs the identity (selfsameness) of substances and properties.
Identity/Millikan: these identities have a structure. They are structured in relation to each other (see above: exclusivity classes).
R. G. Millikan
Language, Thought, and Other Biological Categories: New Foundations for Realism Cambridge 1987