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Full Idea
For simplicity, we can say that 'classical logic' amounts to the truth of four sentences: 1) either p or not-p; 2) it is not the case that both p and not-p; 3) from p and not-p, infer q; 4) from p or q and not-p, infer q.
Gist of Idea
Classical logic is: excluded middle, non-contradiction, contradictions imply all, disjunctive syllogism
Source
Jennifer Fisher (On the Philosophy of Logic [2008], 12.I)
Book Ref
Fisher,Jennifer: 'On the Philosophy of Logic' [Thomson Wadsworth 2008], p.162
A Reaction
[She says there are many ways of specifying classical logic] Intuition suggests that 2 and 4 are rather hard to dispute, while 1 is ignoring some grey areas, and 3 is totally ridiculous. There is, of course, plenty of support for 3!
| 8946 | We could make our intuitions about heaps precise with a million-valued logic [Fisher] |
| 8941 | We can't explain 'possibility' in terms of 'possible' worlds [Fisher] |
| 8943 | Three-valued logic says excluded middle and non-contradition are not tautologies [Fisher] |
| 8945 | Fuzzy logic has many truth values, ranging in fractions from 0 to 1 [Fisher] |
| 8944 | Vagueness can involve components (like baldness), or not (like boredom) [Fisher] |
| 8947 | If all truths are implied by a falsehood, then not-p might imply both q and not-q [Fisher] |
| 8949 | In relevance logic, conditionals help information to flow from antecedent to consequent [Fisher] |
| 8950 | Logic formalizes how we should reason, but it shouldn't determine whether we are realists [Fisher] |
| 8951 | Classical logic is: excluded middle, non-contradiction, contradictions imply all, disjunctive syllogism [Fisher] |
| 8952 | We reach 'reflective equilibrium' when intuitions and theory completely align [Fisher] |