more from this thinker     |     more from this text


Single Idea 9719

[filed under theme 5. Theory of Logic / K. Features of Logics / 3. Soundness ]

Full Idea

If every proof-theoretically valid inference is semantically valid (so that |- entails |=), the proof theory is said to be 'sound'.

Gist of Idea

A proof theory is 'sound' if its valid inferences entail semantic validity

Source

Herbert B. Enderton (A Mathematical Introduction to Logic (2nd) [2001], 1.1.7)

Book Ref

Enderton,Herbert B.: 'A Mathematical Introduction to Logic' [Academic Press 2001], p.2


The 12 ideas with the same theme [whether all formal deductions always lead to truth]:

If soundness can't be proved internally, 'reflection principles' can be added to assert soundness [Gödel, by Halbach/Leigh]
A proof theory is 'sound' if its valid inferences entail semantic validity [Enderton]
Soundness would seem to be an essential requirement of a proof procedure [Tharp]
If everything that a theory proves is true, then it is 'sound' [Smith,P]
Soundness is true axioms and a truth-preserving proof system [Smith,P]
A theory is 'sound' iff every theorem is true (usually from true axioms and truth-preservation) [Smith,P]
'Weakly sound' if every theorem is a logical truth; 'sound' if every deduction is a semantic consequence [Shapiro]
Soundness is a semantic property, unlike the purely syntactic property of consistency [George/Velleman]
Soundness theorems are uninformative, because they rely on soundness in their proofs [McGee]
You cannot just say all of Peano arithmetic is true, as 'true' isn't part of the system [Halbach]
Normally we only endorse a theory if we believe it to be sound [Halbach]
Soundness must involve truth; the soundness of PA certainly needs it [Halbach]