Full Idea
Bolzano said the 'laws of thought' (identity, contradiction, excluded middle) are true, but nothing of interest follows from them. Logic obeys them, but they are not logic's first principles or axioms.
Gist of Idea
The laws of thought are true, but they are not the axioms of logic
Source
report of Bernard Bolzano (Theory of Science (Wissenschaftslehre, 4 vols) [1837], §3) by George / Van Evra - The Rise of Modern Logic
Book Reference
'A Companion of Philosophical Logic', ed/tr. Jacquette,Dale [Blackwell 2002], p.39
A Reaction
An interesting and crucial distinction. For samples of proposed axioms of logic, see Ideas 6408, 7798 and 7797.
Related Ideas
Idea 6408 Russell needed three extra axioms to reduce maths to logic: infinity, choice and reducibility [Grayling]
Idea 7798 There are three axiom schemas for propositional logic [Girle]
Idea 7797 Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems [Girle]