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Single Idea 15431

[filed under theme 4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic ]

Full Idea

The question of the completeness of the full intuitionistic logic for its intended interpretation is not yet fully resolved.

Clarification

'Complete' means all its truths can be proved

Gist of Idea

It is still unsettled whether standard intuitionist logic is complete

Source

John P. Burgess (Philosophical Logic [2009], 6.9)

Book Ref

Burgess,John P.: 'Philosophical Logic' [Princeton 2009], p.141


The 15 ideas with the same theme [logic which uses 'provable' in place of 'true']:

Mathematical statements and entities that result from an infinite process must lack a truth-value [Dummett]
Dummett says classical logic rests on meaning as truth, while intuitionist logic rests on assertability [Dummett, by Kitcher]
Classical interdefinitions of logical constants and quantifiers is impossible in intuitionism [Bostock]
Intuitionists rely on assertability instead of truth, but assertability relies on truth [Kitcher]
Is classical logic a part of intuitionist logic, or vice versa? [Burgess]
It is still unsettled whether standard intuitionist logic is complete [Burgess]
You can employ intuitionist logic without intuitionism about mathematics [Sider]
Intuitionist logic looks best as natural deduction [Mares]
Intuitionism as natural deduction has no rule for negation [Mares]
(∀x)(A v B) |- (∀x)A v (∃x)B) is valid in classical logic but invalid intuitionistically [Beall/Restall]
Double negation elimination is not valid in intuitionist logic [Friend]
Showing a disproof is impossible is not a proof, so don't eliminate double negation [Colyvan]
Rejecting double negation elimination undermines reductio proofs [Colyvan]
It is the second-order part of intuitionistic logic which actually negates some classical theorems [Rumfitt]
Intuitionists can accept Double Negation Elimination for decidable propositions [Rumfitt]