CARTESIANISM

A term which, strictly speaking, means ‘of, or bearing some relation to, the thought of philosopher Rene´ Descartes’ (1596-1650). However, ‘Cartesianism’ has also come to signify a metaphysical viewpoint that bears upon issues of personal identity, the nature of the self, and also questions in epistemology. In reply to the writings of contemporary sceptics who questioned

whether we can have any certain knowledge, Descartes’s writings seek to show that there is at least one certain piece of knowledge we are in possession of. Arriving at this view, he argues, involves employing what is termed the ‘sceptical method’. Thus, Descartes resolves to ‘demolish’ all his beliefs, and afterwards attempts to construct the foundations of knowledge as stable and lasting science. In order to do this, it is sufficient merely to bring into question all one’s opinions, i.e. to show that they are not certain, rather than that they are false. For instance, what we often accept as true are beliefs derived from experience (from the senses). But, the senses can deceive us, so many beliefs derived from them can be doubted. But some beliefs cannot be doubted: ‘for example, that I am here, sitting by the fire, wearing a winter dressing gown holding this piece of paper in my hands, and so on’. However, taking his scepticism one step further, Descartes asks how can we distinguish between being awake and asleep? Having sensations could be a product of the imagination; nevertheless, even if the sensation of having a body is merely a dream, there are some things (‘simpler and universal’, of which bodies are made up) which are real, i.e. notions of quantity, shape, size and number. Thus, we can distinguish between the physical sciences (physics,

astronomy, etc.) which depend upon composite notions (they conceive of objects as having specific sizes, shapes, etc.), and other forms of knowledge (e.g. geometry, mathematics) which do not. Whether we are asleep or awake 2 + 3 = 5 and a square has four sides. Some might argue that the existence of an omnipotent God guarantees that these beliefs are true. But suppose that ‘I am so imperfect as to be deceived all the time’. Then, even these beliefs are doubtful. Suppose that ‘not God [ . . . ] but rather some malicious demon of the utmost power and cunning has employed all his energies to deceive me’. I might think 2 + 3 = 5, but I am being fooled. What then? According to Descartes, one thing remains true: even if I am being

deceived, I am still thinking: ‘I must conclude that this proposition, I am, I exist, is necessarily true whenever it is put forward or conceived by me in my mind’. This is most famously expressed in the phrase ‘I

think, therefore I am’ (cogito, ergo sum). But, what is this ‘I’ that thinks? (i) There is the mechanical structure of the human body. (ii) There are the activities which humans pursue: they walk about, eat, have perceptions from their senses, etc. On Descartes’s view, these activities are the actions of a ‘soul’ or ‘mind’, which is a different kind of substance from physical stuff. The properties of a body are physical: it can be seen, moved, occupies

a particular space, etc. The ‘power of self-movement’, however, is not a property we can attribute to a physical body. Given the presence of his malicious demon, Descartes thinks that the existence even of the body can be doubted. But the self that thinks cannot: ‘At present I am not admitting anything except what is necessarily true; that is, I am a mind, or intelligence, or intellect, or reason [ . . . ] a thinking thing’. Descartes thus holds that he is a mind, ‘not that structure of limbs which is called a human body’. In this way Descartes’s mind-body (or ‘Cartesian’) dualism is thereby set firmly in place. What is essential about him, he contends, is that he is a mind, not a body. In other words, he is essentially a thinking thing, and mind is essentially different from body. From the standpoint of epistemology, what is notable about Des-

cartes’s argument is that it is subjectivity (the ‘I think’) that forms the foundation of knowledge. Moreover, the conception of subjectivity that Descartes proposes is thus one that is not constrained by the social world. Indeed, it is (at least purportedly) derived independently of any assumptions about the nature of society or even material reality. Hence, the relationship between the human subject and the external world which it experiences is accounted for by way of a model which places the subject ‘outside’ the world, as a kind of observer who is not implicated in it. There have been a number of criticisms of this view. For instance, the German philosopher, Martin Heidegger (1889-1976), offers an account of the subject that is directly opposed to this central presupposition of Cartesianism. For Heidegger, the subject (or, more properly Dasein) is not a passive observer of experience, but is actively engaged in its own world. Thus, on Heidegger’s view, human subjects are not ‘in’ the world in the same sense that a match might be said to be ‘in a match box’. Rather, we are ‘in the world’ in a concrete sense that cannot be divorced from our actual Being. Hence, our world cannot be viewed from an ‘objective’ perspective that is external to it, as a spectator sitting in the stalls of a theatre might be said to view the events that unfold in a play. Rather, we actively relate to our world, and this relationship is constitutive of that world. Thus, for example, in addition to our ability to conceptualise objects we can also relate to them

as things we can grasp in a practical sense (in Heidegger’s parlance, they are not merely ‘present-at-hand’ but ‘ready-to-hand’). On Heidegger’s view, Cartesianism cannot provide us with an adequate account of how this latter form of relationship to the objects in our world is possible because it has driven an irreconcilable wedge between cognition and what is conceived. The Cartesian thesis has important cultural ramifications, in so far

as traditional scientific forms of discourse presuppose a notion of subjectivity which has much in common with this model (i.e. the notion of a passive or neutral observer). Equally, the history of modern philosophy (by which is usually meant philosophy after Descartes) is marked by a critical (and sometimes not so critical) engagement with many of the central tenets of Cartesianism.