ABSTRACT
This chapter investigates the relationships between the M3 (cognitive artefacts), M1 (for brevity) and M2 (will and attention), and discusses some demarcation issues: whether M3 activities are a subclass of M2 activities, and whether one should postulate continuity between the four modes. It discusses the proprietary computations of M3 (such as shunting information, bridging cognitive modules, displacing search processes, or restructuring memory search). Other targets are popular metaphors such as the "extended mind" and "the world as external memory" that, by making the M3 look too much like M4 (relevant mental activity), risk missing out on the specific properties of brain-artifact interaction. The psychological literature has accepted a distinction between two "systems", or two modes of operation of the brain in certain tasks, mainly reasoning and decision-making tasks. M1 and M2 modes would then correspond to natural psychological kinds, tokened in different brain circuitries. The same can very well be the case for M3, and (relatively trivially) for M4.
