Abstract

The subject of mental processes or mental states is usually assumed to be an individual, and hence the boundaries of mental features – in a strict or metaphorical sense – are naturally regarded as reaching no further than the boundaries of the individual. This chapter addresses various philosophical developments in the 20th and 21st century that questioned this natural assumption. I will frame this discussion by fi rst presenting a historically infl uential commitment to the individualistic nature of the mental in Descartes’ theory. I identify various elements in the Cartesian conception of the mind that were subsequently criticized and rejected by various externalist theories, advocates of the extended mind hypothesis and defenders of embodied cognition. Then I will indicate the main trends in these critiques.