Full Idea
Many-valued logics do not have reasonable natural deduction systems.
Gist of Idea
Many-valued logics lack a natural deduction system
Source
Edwin D. Mares (Negation [2014], 1)
Book Reference
'Bloomsbury Companion to Philosophical Logic', ed/tr. Horsten,L/Pettigrew,R [Bloomsbury 2014], p.182