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Single Idea 12005

[from 'The Metaphysics of Modality' by Graeme Forbes, in 4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / a. Symbols of PL ]

Full Idea

We use the symbol 'ι' (Greek 'iota') to form definite descriptions, reading (ιx)F(x) as 'the x which is such that F(x)', or simply as 'the F'.

Gist of Idea

The symbol 'ι' forms definite descriptions; (ιx)F(x) says 'the x which is such that F(x)'

Source

Graeme Forbes (The Metaphysics of Modality [1985], 4.1)

Book Reference

Forbes,Graeme: 'The Metaphysics of Modality' [OUP 1985], p.72


A Reaction

Compare the lambda operator in modal logic, which picks out predicates from similar formulae.