Where is the fallacy, do you think, in Seth Yalcin’s argument (2012) that the Modus Tollens is not a generally valid form of argument?
Seth Yalcin’s counterexample to the Modus Tollens (MT) https://link.springer.com/article/10.1007/s10992-012-9228-4
An urn contains 100 marbles, a mix of blue and red, big and small:
Big & Blue 10
Small & Blue 50
Big & Red 30
small & Red 10
A marble is then drawn at random.
Seth Yalcin's counterexample:
(P1) If the marble is big, then it’s likely red.
(P2) The marble is not likely red.
(C1) The marble is not big.
Seth Yalcin observes that the conclusion does not follow, but that it should follow if the MT was generally valid, and so the MT is not generally valid.
Schematically, the argument is of the following form:
φ → probably ψ
¬ probably ψ
∴ ¬ φ
where φ and ψ are themselves assumed to be free of probability operator.
Seth Yalcin asserts about the schematic form:
"This argument form is invalid. Since it is just a special case of MT, it is a counterexample to the claim that MT is a generally valid pattern."