<logic, philosophy of science> the solution proposed by Russell for the self-referential paradox that arises from the notion of "the class of all classes that are not members of themselves." Russell envisioned an indefinite hierarchy of types to be symbolized: ordinary objects; the properties and relations of ordinary objects; the features of properties of objects; etc. Defining each item by reference only to those of a lower type avoids paradox, but may not resolve every instance of difficulty with self-reference. Recommended Reading: Irving M. Copi, The Theory of Logical Types (Routledge, 1971); Bertrand Russell, Introduction to Mathematical Philosophy (Dover, 1993); and Roy L. Crole, Categories for Types (Cambridge, 1994).
[A Dictionary of Philosophical Terms and Names]
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