¹ Morton, Adam, “If I were a Dry Well-Made Match”, Dialogue, vol. xii, no. 2, pp. 322–324Google Scholar. Morton attributes the principle cited here to Goodman (Fact, Fiction, and Forecast), among others.

² I follow Morton's use of ‘⊃’ “→’ and ‘◊’ as symbols for material implication, subjunctive implication, and causal possibility, respectively.

³ At least, it is not clear on what grounds Morton could reject the subjunctive conditional here, while holding on to the rather odd causal law derived by way of his principle.