As I see it, the major cognitive limitation of an organism lacking memory capacity is that it would be unable to acquire new patterns of behaving, as new patterns would have to be stored or encoded somewhere in the organism. How could an organism show that it had cognitive mental states, if it was unable to acquire new patterns of behaviour?

We can tentatively formulate the following conclusion:

N.10 The existence of memory capacity in an organism is a necessary condition for ascribing cognitive mental states to it.

(We will re-visit this conclusion below, in our discussion of Conclusion S.7, which gives it a firmer basis. Affective mental states will be discussed in chapter 3.)

What we have been considering here is an organism which never manifests a capacity to remember at any stage of its development. Such an organism lacks what might be called a "natural capacity" to form memories: that is, the internal program that directs its biological development does not encode for the creation of structures with a memory capacity. Following the methodology adopted here, such an organism should be regarded as mindless.

The situation is different if we consider the case of an impaired individual which has lost its capacity to remember, due to physical deterioration or trauma. Let us suppose that the individual's behavioural repertoire was rich enough to warrant our ascribing mental states to it while it had a memory. We might be inclined to say that such an individual retained the capacity to perceive or feel, despite losing its memory, if it retained enough of its old behavioural repertoire. Incidentally, there are no cases of human individuals (not even the celebrated H.M.) who have completely lost their capacities to form memories.

The upshot of our enquiry into memory is that the existence of memory capacity in an organism is a necessary but not a sufficient ground for ascribing cognitive mental states to it.