 If so, the fact that  (6)  is acceptable in Russian does not establish that the interrogative form in Russian cannot also have an interpretation (the de se interpretation) on which it is truth conditionally equivalent to the Russian’s infinitival form. Here is a competitive explanation of the available cross-linguistic evidence that does not commit us to the Ambiguity Hypothesis. Just like English’s ascriptions, the interrogative form in Russian is ambiguous between a de se interpretation, on which it is truth conditionally equivalent to the infinitival form, and a generic interpretation of the subject of the infinitival embedded verb, on which it comes apart from the infinitival form. This explains why  (6)  is felicitous and why it can be translated as (7) but not as (8). On this explanation, this evidence might be compatible with English knowledge-how ascriptions univocally having the same logical form (the interrogative form), even though the embedded interrogative can receive either the generic or the de se interpretation, depending on the subject of the infinitival embedded verb.