more from JC Beall / G Restall

### Single Idea 13249

#### [catalogued under 4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic]

Full Idea

The inference of 'distribution' (∀x)(A v B) |- (∀x)A v (∃x)B) is valid in classical logic but invalid intuitionistically. It is straightforward to construct a 'stage' at which the LHS is true but the RHS is not.

Gist of Idea

(∀x)(A v B) |- (∀x)A v (∃x)B) is valid in classical logic but invalid intuitionistically

Source

JC Beall / G Restall (Logical Pluralism [2006], 6.1.2)

Book Reference

Beall,J/Restall,G: 'Logical Pluralism' [OUP 2006], p.64

A Reaction

This seems to parallel the iterative notion in set theory, that you must construct your hierarchy. All part of the general 'constructivist' approach to things. Is some kind of mad platonism the only alternative?