Keith Frankish

Questions about the relation between mind and world have long occupied philosophers of mind. In _Consciousness in Action_ Susan Hurley invites us to adopt a ninety-degree shift and consider the relation between perception and action. The central theme of the book is an attack on what Hurley dubs the _Input-Output Picture_ of perception and actionthe picture of perceptions as sensory inputs to the cognitive system and intentions as motor outputs from it, with the mind occupying the buffer zone in between. Hurley argues that this picture confuses the personal level of normatively constrained mental contents and the subpersonal level of causal processes sustaining the mind. The notions of perception and action belong to the former, those of input and output to the latter. In place of the Input-Output picture, Hurley proposes a _Two-level _ _Interdependence View_. At the subpersonal level, she points out, there are not only one-way processes from input to output but also a host of feedback loops from output to inputsome internal to the central nervous system, some of wider orbit, involving proprioception, for example, or visual feedback on movement. The system as a whole can be seen as a _dynamical singularity_a tangle of sensorimotor feedback loops centred on the organism but extending out into the world beyond. The processes at this level are the vehicles of perceptions and actions, but, Hurley insists, the two levels cannot be mapped onto each other in a simple way. Changes on the output side may affect the content of perceptions, and changes on the input side may affect that of intentions. Perception and intention are in this way _interdependent_. The point here is not the uncontroversial one that perceptions and intentions can _cause_ changes in each other. That would be compatible with the Input-Output Picture. The dependency, in Hurleys view, is not instrumental, but _constitutive_: the contents of perceptions and intentions are each constituted by processes involving both inputs and outputs..