Analysis: For brevity, define 'gone' = 'gone to the party'.
In this scenario, while it is true that had P gone, then A would have gone,
and it is true that if A would have gone, then M would have gone,
it is NOT true that had P gone, then M would have gone.
If A had gone to the party, P still would not have gone, but M would have gone (because he heard about P's arrest). The first ... and ... second premise[s are] true. This exceptional case proves that this form of argument is invalid, because it overlooks the possibility that
even if P had gone, M would still not have gone...
Notice, however, we may avoid the fallacy if we could assume that if A would have gone, then P would have gone. Sometimes by adding another premise we can rule out all cases where transitivity fails. But in this scenario, we need not make that assumption.
Conclusion: Transitivity does not always fail for counterfactual arguments, but since it does sometimes, hypothetical syllogisms are unreliable and thus invalid.
1. Please explain how the bolded would 'avoid the fallacy'?
2. In general, what 'premise(s)' can be added, or are required. to ensure transitivity?