Roles for Morphology in Computation ^†

The morphological aspects of a system are the shape, geometry, placement and compliance properties of that system. On the rather permissive construal of computation as transformations of information, a correspondingly permissive notion of morphological computation can be defined: cases of information transformation performed by the morphological aspects of a system. This raises the question of what morphological computation might look like under different, less inclusive accounts of computation, such as the view that computation is essentially semantic. I investigate the possibilities for morphological computation under a particular version of the semantic view. First, I make a distinction between two kinds of role a given aspect might play in computations that a system performs: foreground role and background role. The foreground role of a computational system includes such things as rules, state, algorithm, program, bits, data, etc. But these can only function as foreground by virtue of other, background aspects of the same system: the aspects that enable the foreground to be brought forth, made stable/reidentifiable, and to have semantically coherent causal effect. I propose that this foreground/background distinction cross-cuts the morphological/non-morphological distinction. Specifically, morphological aspects of a system may play either role.