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It is not the case that The formula (p → q) ∨ p is classically valid because if p is false, conditionals with false antecedents are vacuously true
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Reasons For
2 perspectives
Reason for 1 of 2
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1.
Vacuous truth is a formal artifact of material implication, not a feature of genuine conditional reasoning (Anderson & Belnap, Entailment, 1975).
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2.
Relevant logic requires that antecedent and consequent share propositional variables for a conditional to be valid, which p→q need not satisfy.
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3.
Under relevant logic, (p→q)∨p fails when p and q are relevantly independent, undermining the claim's universality.
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Reason for 2 of 2
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1.
Intuitionistic logic rejects classical truth-value bivalence, so 'p is false' cannot be assumed whenever 'p fails' (Dummett, Elements of Intuitionism).
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2.
Without bivalence, a false antecedent cannot be established merely from the absence of proof of p, blocking the vacuous truth inference in constructive settings.
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Reasons Against
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Reason against
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1.
If p fails, p is false
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2.
In classical logic, a conditional with a false antecedent is true
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3.
Therefore (p → q) holds whenever p is false, making (p → q) ∨ p a tautology
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