10 THE BOUNDARIES OF THE MIND Katalin Farkas The Cartesian conception of the mind 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 first presenting a historically influential 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 Descartes’ work was partly a response to developments in natural science in the 17th century, and one of his goals was to provide a theoretical-philosophical foundation for modern science which rejected Aristotelian natural philosophy Descartes was not the last philosopher who hoped to make a lasting contribution by providing a theory that integrates philosophy with modern science Ever since the 17th century, there has been an occasionally reoccurring anxiety in philosophy – famously expressed for example by Kant in the Critique of Pure Reason – about the fact that while the sciences appear to make great progress, philosophy in comparison seems to make very little, if any progress Various remedies have been suggested, for example by offering a methodology or grounding for philosophy that is either imported from the sciences, or is comparable to the objectivity and explanatory power of scientific method This will be one of the persisting themes in this chapter In section 2, we will see how the attempt to ground philosophical theories by semantics offers the hope of progress and questions the Cartesian boundaries of the mind at the same time In section 3, we will see how naturalism about the mind also leads to reconsidering the issue of boundaries Descartes’ considerations about the nature of the mind in his Second Meditation have had a profound effect on the development of philosophy in the Western tradition.2 In the First Meditation, Descartes considers the possibility of being deceived by an evil demon The starting point is the simple observation that things 256