Generics: Cognition and Acquisition

Philosophers of language sometimes theorize about obscure sentences, rarely found in everyday discourse, or about the applicability of sentences to strange, unrealized possible circumstances. Ordinary speakers of English often lack clear intuitions about the truth or falsity of these sentences, and so the theorizing is based on the judgments of the select few whose intuitions are sufficiently honed. Other times, however, one need not venture into obscurity to find a phenomenon worthy of attention. If one so chooses, one may ask any English speaker whatsoever whether sentences such as ‘tigers have stripes’, ‘birds lay eggs’, or ‘mosquitoes carry the West Nile virus’ are true, or whether ‘mosquitoes don’t carry the West Nile virus’ and ‘birds are female’ are false. The response is invariably confident and immediate. These simple examples present a puzzle with no simple solution. That ‘tigers have stripes’ is true might not seem particularly troubling; even if some tigers lack stripes, most tigers sport them. Examples such as ‘birds lay eggs’, though, indicate that it is not necessary for the truth of these sentences that the majority of the kind in question satisfy the predicate; most birds do not lay eggs, yet ‘birds lay eggs’ is true. Closer