Full Idea
In contrast with axiomatic systems, in natural deductions systems of logic neither the premises nor the conclusions of steps in a derivation need themselves be logical truths or theorems of logic.
Gist of Idea
Unlike axiom proofs, natural deduction proofs needn't focus on logical truths and theorems
Source
Bob Hale (Necessary Beings [2013], 09.2 n7)
Book Reference
Hale,Bob: 'Necessary Beings' [OUP 2013], p.205
A Reaction
Not sure I get that. It can't be that everything in an axiomatic proof has to be a logical truth. How would you prove anything about the world that way? I'm obviously missing something.