We already have a distinction between the intension and extension of terms. This is not simply the distinction that is operative in philosophy of mind, body, and action. There, the concern is with things, and with a physicalistic or a mentalistic account of them. The physicalist says he supports an ‘extensional’ analysis of things, the mentalist an ‘intensional’. So, the physicalist says that, in the end, only ‘the extensional language of physical science’ will do in ontology. But, associating this physical-mental (...) dichotomy with the intension-extension distinction as applied to terms is misleading. The ontological issue is obscured by the association. An ontologist wants, like Spinoza or Berkeley, to know whetherthingsare extended or not, and in what respects. This question makes central the concept of space, or more generally of ‘field’, ‘domain’. Unfortunately, the same word ‘extension’ is used also for the spread or location of athingin space. To dissociate the extension of a term, a logical notion, from the ontological notion of the spatial status of a thing, I introduce the new word ‘extention’. This coinage correlates, not with the ‘intension’ of terms—the logical correlate of ‘extension’—but with ‘intention’, a word that fortunately already has common currency, and reeks with connotations that have logical ties with ‘consciousness’. So, from here on, we have two dichotomies: intension-extension applying to terms, and intention-extention applying to things. Since terms are things, both sorts of considerations are relevant to them, the logical one and the ontological. Only the latter applies to, say, stones or persons, since these are not linguistic terms. (shrink)