So far the argument has been that if there is to be a rapprochement between the extensional physical sciences and ‘the language of the mind’ – whether our ordinary Intentional discourse or the statements of a ‘science of Intention’ – we must find a rationale and justification for ascribing content to certain internal states and events of the behavioural control system. And since Intentional explanations presuppose the appropriateness of the sequences of events they purport to explain (see Chapter 2), part of the burden of such content ascription is providing an account of the generation of structures to direct these generally appropriate sequences. It was to meet this requirement that we proposed hypotheses about evolution, both of species and of neural structures. Put another way, since environmental significance is extrinsic to any physical features of neural events, and since the useful brain must discriminate its events along lines of environmental significance, the brain’s discriminations cannot be a function of any extensional, physical descriptions of stimulation

and past locomotion alone. Rather, some capacity must be found in the brain to generate and preserve fortuitously appropriate structures. It was then argued that a close analogue of natural selection of species would be a system that could provide this capacity and could itself be provided for by natural selection of species. The system was developed just enough to provide some answer to the question of whether it could control goal-directed behaviour, but it will provide us with footholds for the next task: determining the conditions under which one could justifiably ascribe content to neural states.