more from Penelope Maddy

### Single Idea 18168

#### [catalogued under 5. Theory of Logic / E. Structures of Logic / 1. Logical Form]

Full Idea

A 'propositional function' is generated when one of the terms of the proposition is replaced by a variable, as in 'x is wise' or 'Socrates'.

Gist of Idea

'Propositional functions' are propositions with a variable as subject or predicate

Source

Penelope Maddy (Naturalism in Mathematics [1997], I.1)

Book Reference

Maddy,Penelope: 'Naturalism in Mathematics' [OUP 2000], p.9

A Reaction

This implies that you can only have a propositional function if it is derived from a complete proposition. Note that the variable can be in either subject or in predicate position. It extends Frege's account of a concept as 'x is F'.