ABSTRACT
This chapter presents evidence that counter to the assumption implicit in all previous research on conceptual representation, the conceptual systems do, in fact, treat certain entities as exceptional. Some evidence that the common sense conception of things like dogs and chairs contain necessary connections to certain properties comes from generic sentences. A third type of evidence that shows that the conceptual systems represent certain necessary relations between being a certain kind of thing and having certain properties comes from redundancy effects in prenominal modification. On the one hand, there is evidence that we conceive of there being necessary connections between things like being a dog and being fourlegged, while on the other hand, we find no problem in conceiving of the existence of three-legged dogs. While this is a perfectly legitimate thing to do, there are important qualitative differences between representing probabilistic defaults, and rule-based defaults that involve necessary connections.
