JM: We had spoken earlier about the distinctiveness of human concepts, and I'd like to get a bit clearer about what that amounts to. I take it that, at least in part, it has to do with the fact that human beings, when they use their concepts – unlike many animals – do not in fact use them in circumstances in which there is some sort of direct application of the concept to immediate circumstances or situations.

NC: Well, as far as anyone knows – maybe we don't know enough about other animals – what has been described in the animal literature is that every action (local, or whatever) is connected by what Descartes would have called a machine to either an internal state or an external event that is triggering it. You can have just an internal state – so the animal emits a particular cry [or other form of behavior] ‘saying’ something like “It's me” or “I'm here,” or a threat: something like “Keep away from me,” or maybe a mating cry. [You find this] all the way down to insects. Or else there is a reaction to some sort of external event; you get a chicken that's looking up and sees something that we interpret as “There's a bird of prey” – even though no one knows what the chicken is doing. It appears that everything is like that, to the extent – as mentioned before – that Randy Gallistel (1990) in his review introduction to a volume on animal communication suggests that for every animal down to insects, whatever internal representation there is, it is one-to-one associated with an organism-independent external event, or internal event. That's plainly not true of human language. So if [what he claims] is in any way near to being true of animals, there is a very sharp divide there.

JM: That's a sharp divide with regard to what might be called the “use” or application of relevant types of concepts, but I take it that it's got to be more than that . . .

NC: Well, it's their natures. Whatever the nature of HOUSE, or LONDON, ARISTOTLE, or WATER is – whatever their internal representation is – it's just not connected to mind-independent external events, or to internal states. It's basically a version of Descartes's point, which seems accurate enough.