Rational Animals

Neither an infant one week old nor a snail is a rational creature. I f the infant survives long enough, he will probably become rational, while this is not true of the snail. If we like, we may say of the infant from the start that he is a rational creature because he will probably become rational i f he survives, or because he belongs to a species with this capacity. Whichever way we talk, there remains the difference, with respect to rationality, between the infant and the snail on one hand, and the normal adult person on the other; this difference is discussed here. The difference consists, i t is argued, in the having of propositional attitudes such as belief, desire, intention and shame. This raises the question how to tell when a creature has propositional attitudes; snails, we may agree, d o not, but how about dogs or chimpanzees? The question is not empirical; the question is what sort of empirical evidence is relevant to deciding when a creature has propositional attitudes. It is next contended that language is a necessary concomitant of any of the propositional attitudes. This idea is not new, but there seem to be few arguments in its favor in the literature; one is attempted here. Crucial to the considerations advanced is the idea that belief depends on having the concept of objective truth, and that this comes only with language.