The Philosophy of Rene Descartes

By NASRULLAH MAMBROL on May 9, 2017 • ( 14 )

French philosopher, scientific theorist and mathematician Rene Descartes (1596-1650) was a student at the Jesuit College in La Fleche and then studied law at Poitiers, graduating in 1616. Shortly afterwards he became a member of the Duke of Bavaria’s army, and travelled to Holland and Germany. It was in 1619 in Bavaria that Descartes first wrote down some of his thoughts on philosophy. These thoughts, subsequently presented in the Discourse on Method (1637) and Meditations on First Philosophy (1641), were to exert a profound influence on modern philosophy, effectively determining many of its central concerns for over two hundred years. Descartes’s first major completed work was Le Monde (1632) which presented a theory of the origins and functioning of the solar system. A central feature of this work is its adherence to the Copernican theory, which holds the earth to orbit the sun. In the wake of Galileo‘s condemnation by the Catholic Church, Descartes decided against publication. In 1637 he published a work that sought to present his scientific theories, the Dioptric, Meteors, and Geometry; the Discourse on Method formed the theoretical introduction to this work.

In the Discourse and the Meditations Descartes set out to offer a theory of knowledge immune to the criticism of scepticism. A sceptic is someone who argues that nothing can be known for certain, a view espoused in the writings of Descartes’s near contemporary Michel de Montaigne (1533—1592). Against this view, Descartes aims to illustrate that there is at least one piece of knowledge that all humans have and cannot doubt. In order to show this he employs the ‘sceptical method‘. This method begins by doubting everything that it is possible to doubt and seeing if there is anything that remains immune to such doubt. Starting in this way, Descartes argues, will thus enable us to discover the foundations of knowledge. Once we have done this we will be in a position to articulate the structure upon which a lasting science can rest. It would, of course, be unfeasible to sift through all of one’s beliefs and show each of them in turn to be false. So, Descartes begins bringing into question the beliefs that form the ‘foundation’ for all the rest (Descartes 1999, p. 60). So, he begins by casting doubt on the veracity of the evidence given to us by our senses. In turn, we can also doubt other beliefs: for example, how is it possible to distinguish with certainty between being awake and dreaming? Likewise, Descartes also questions his own belief in ‘corporeal nature in general’, e.g. notions of extension, quantity, shape, size, time, place, number and so forth. All these notions, he concludes, can be doubted and hence cannot serve as a means for providing us with a form of knowledge that is immune to the corrosive power of doubt. Famously, Descartes envisages a scenario in which he is under the control of an omnipotent ‘evil genius’ who is deceiving him about both his experiences and judgements. Such a being could even mislead him into believing that 2 + 2 = 4, when in reality it equals 5. In spite of this, Descartes argues, one thing remains certain ‘[A]fter everything has been most carefully weighed, it must finally be established that this pronouncement “I am, I exist” is necessarily true every time I utter it or conceive it in my mind’ (p. 64). Thus, however deceived he may be, Descartes is now in a position to assert one truth that cannot be doubted. Whatever else may be the case, it is always true that he exists. In turn, Descartes attempts to define what this existing being is. Above all, he concludes, he is a being who thinks, i.e. he is one who doubts, has understanding, is capable of affirming and denying things, and so forth. Thus, Descartes arrives at the conclusion that he himself can be characterised in one manner above all others: his existence is defined by thought. This view is famously expressed in Part Four of the Discourse on Method by the sentence I think, therefore l am (p. 19).

According to Descartes, the T that thinks can be defined by way of drawing a distinction between the mechanical structure of the human body and the fact that human activities are always exhibitions of intelligence. Because of this, he argues, all human actions are manifestations of a soul or mind. The properties of bodies are physical, in that they can be seen, touched, occupy a particular space, etc. But the veracity of the body can always be doubted. The self that thinks, however, cannot be doubted, for it is the self that is engaged in the act of doubting. In this way Descartes formulates the basis for his dualistic account of the relationship between mind and body. According to this view, mind is a substance that is essentially different from bodily substance. This distinction, in turn, forms the basis for Descartes’s conception of knowledge. Certainty emanates from the ‘I think’, that is, from the self conceived of as a mental substance that is different in kind from that other substance we call ‘matter’.

The metaphor of a building is a key element within Descartes’s account of knowledge in both the Discourse and the Meditations. Knowledge, he claims, is like an edifice, and any edifice must be erected upon a secure foundation. The cogito (the ‘I think’) is that foundation. In this sense, Descartes, like any builder of a house, is building his account of knowledge by starting with the foundation and working his way up from there. What is special about the mind, he then argues, is that it has the ability to act and reflect in a spontaneous manner. Humans are endowed with independent will and reflective ability and it is ‘reason or good sense [. . .] alone makes us men and distinguishes us from animals’ (p. 2). We are above all for Descartes rational beings, and our ability to use our reason implies that we are endowed with ‘intellect’. It is our intellect rather than our senses, he contends, which actually reveals the physical world to us (p. 69). Because human beings are rational they are able to think of the world about them in manner that is meaningful. In turn, since we are definable as the possessors of intellect, it follows that we think of the physical world by using ideas (i.e. concepts) to make ‘representations’ of the things in it. The truest ideas, Descartes contends, will be those of such ‘clarity and distinctness’ that we cannot find good cause to doubt them (p. 11).

Rationality, for Descartes, is a ‘universal instrument’ that provides us with the means of evaluating what counts as ‘knowledge’. This conception of reason’s universality and instrumental value is a central feature of Descartes’s philosophy. Equally important is the fact that Descartes derives his theory solely from the act of rational introspection. For him, merely contemplating what he is in isolation from his environment is sufficient for securing a foundation for knowledge. A number of problems attend Descartes’s approach. Even if we were to be convinced that we are rational beings made of a substance called ‘mind’, Descartes has not shown how knowledge of the external world is possible. Descartes’s answer to this problem is hardly convincing, since he argues that God must be the sole guarantor of a reality external to the mind. The kind of argument he uses to assert the existence of God is referred to as an ‘ontological argument’. According to this argument, if I am able to have a clear and distinct conception of God in my mind then the cause of this conception cannot be attributed to me. This is because I am finite, and it is impossible that a finite being should be the source of the attribute of infinite perfection that characterises God (see Meditation 3). To this is added the claim that existence is a necessary attribute of God’s perfection because it is more perfect to exist than not to exist (see Meditation 5). This being the case, God must exist. In turn, God’s existence allows Descartes to argue for knowledge of the external world. Essential to God’s perfection, Descartes claims, is the fact that he is truthful. If God is truthful then he would not allow us to be deceived with regard to the perceptions that we have by way of our senses. An obvious objection to Descartes’s argument would be to hold that it does not make much sense to claim existence is a perfection. Just because for something to be perfect it must necessarily exist does not imply that there is something that exists that is perfect.

Leaving the above issue to one side, however, one can note that Descartes’ major achievement resides in his arguing that the self (the cogito) constitutes the core of any theory of knowledge. Descartes thinks of subjectivity in a manner that has been extremely influential. A subject, on his view, is an entity that, because it has selfconsciousness, has an immediate sense of what it is. A subject, in other words, can be defined by way of its self-awareness. In turn, it is the sense of certainty that accompanies this self-awareness that characterises knowledge in general. If a claim is to count as ‘knowldge’ then it must be certain, i.e. immune to doubt. Equally, the claim is, therefore, that simply by first examining the ‘contents’ of your own mind you will be able to construct a ‘theory of knowledge’ worthy of the title. This view implies an attitude of individualism with regard to issues of knowledge. For Descartes, the individual is taken to be something given. Hence, our sense of individual identity and what accompanies it (rationality, will, our ability to have clear and distinct ideas of things, and so forth) are of such self-evidence that no grounds could be offered for questioning them. Descartes therefore presupposes that an immediate sense of who and what we are constitutes a kind of complete and certain knowledge. In this way, Descartes takes human identity to be in essence rational and conscious and hence immune to the possibility that it may have unconscious and irrational dimensions (his philosophy, in other words, is a ‘philosophy of consciousness’). Moreover, he conceives of the self in essentially a-social and a-historical terms. Thus, from a Cartesian point of view, there cannot be a cultural dimension to either the self or knowledge. Many subsequent thinkers have reacted against this in various ways. Thus, for example, Hume argued that the quest for certainty is a fruitless one, while Hegel argued that human life is in its very nature historical and cannot be comprehended adequately unless the fact of change is accounted for. Other thinkers, such as Nietzsche, Heidegger, Levinas, Foucault and Derrida, have all in various ways challenged the kind of approach that Descartes’s work exemplifies.

Source: Cultural Theory The Key Thinkers by Andrew Edgar and Peter Sedgwick, Routledge