This paper discusses counter‐examples to modus ponens and modus tollens involving modals and quantificational adverbs, and presents new counter‐examples with generic conditionals. We argue that the counter‐examples are spurious, and are explained by the domain‐restricting effects of if ‐clauses. Generic conditionals are especially problematic because the generic operator is silent and detectable only through its interpretive effects. A second, experimental case study involving nested conditionals illustrates the ease with which generic conditionals can mislead theorists about the logic of conditionals. To avoid pitfalls, theorists choosing examples and designing experimental materials must pay close attention to the special linguistic properties of generics.
Lassiter et al. (Mon,) studied this question.