Abstract
In this paper I present experimental data showing that the interpretation of donkey sentences is influenced by certain aspects of world knowledge that seem to elude introspective observation, which I try to explain by reference to a scale ranging from prototypical individuals (like children) to quite marginal ones (such as railway lines). This ontological cline interacts with the semantics of donkey sentences: as suggested already by the anecdotal data on which much of the literature is based, the effect of world knowledge is by and large restricted to donkey sentences with non-intersective determiners. I outline a psychological model which incorporates both ontological and logical factors, and suggest that there may be something wrong with the standard assumption that a statement's receiving a truth value requires that it have a definite reading.