Reasoning about "implies" truth table.
15504
In classical logic, why is $(p\Rightarrow q)$ True if $p$ is False and $q$ is True?
29629
Distinguishing between valid and fallacious arguments (propositional calculus)
87928
Proof of logical equivalence of biconditional and other proposition
128111
Why is a deductive closure an intersection of maximally consistent sets?
122015
"This statement is false" - Propositional Logic
150451
Logic soundness and completeness
73231
Why in implication, if premise is false then implication is true?
9158
Proving that a propositional theory of any cardinality has an independent set of axioms
56325
If we accept a false statement, can we prove anything?
63963
deductive system where the axioms are all the propositions that are not tautology
70500
Implies ($\Rightarrow$) vs. Entails ($\models$) vs. Provable ($\vdash$)
68265
Why is it sensical for a proposition with a false antecedent to validate to true?
57672
Trying to get all this terminology straight in logic
29744
Compactness and axiomatisability
32325
Can there be a valid argument which has a tautology as a conclusion?
140167
Proving $A+A'B=A+B$ without truth tables
136577
In formal logic, how is it possible for an argument with a contradictory conclusion to be valid?