 What about questions? Presumably questions as a category will count as an instance of a linguistic natural kind. Moreover, particular sentences will also count. So, the restriction of the BTT to natural kinds is of little use here. So, what of causal efficiency? Many sentences appear to provoke a wide range of possible responses. In response to, “I went to the zoo last week,” S could think of lions, tigers, bear, giraffes, monkeys, and any number of other natural kinds. But, the question, “What animal goes ‘oink, oink’?”—perhaps uttered in “Motherese” in a clear deliberate fashion so that it is readily comprehensible to a child—will be rather efficient in generating thoughts of a pig. Moreover, it could be more efficient than actual pigs, since a child might have more experience with the question than with actual pigs, often not figuring out that actual pigs are pigs. In such situations, “pig” would turn out to mean “What animal goes ‘oink, oink’?,” rather than pig. So, there appear to be cases in which BTT could make prima facie incorrect content assignments.