Philosopher René Descartes was a rationalist who sought to refute the scepticism of his time – this was due to the people losing trust in the authority of the church thanks to the Scientific Revolution. He wanted to create a new foundation for knowledge and so embarked upon the Meditations, his 6-day diarised quest to find something “firm and lasting in the sciences”. Since he was a rationalist, Descartes wanted to prove the superiority of reason over empirical truth. In this essay I will argue that although the relentlessness of Descartes’ method of doubt is efficient in rejecting empiricism and – to an extent – certifying the precedence of rationalism, he is still subject to conflictions and thus we cannot be convinced of the validity of either foundation.
Descartes’ Meditations aims to provide a clear and certain root for knowledge which science can use to build upon. In order to do this, he must first doubt everything he once believed to be true. This is his ‘Method of Doubt’, also formally known as Cartesian Scepticism (Ortín, 2019). Here, Descartes asserts that he must use a rigorous approach to be able to successfully find something he can be certain of. What this means is that Descartes must follow the rule – if a belief could be false then it should be treated as if it were absolutely false, i.e. that which is true or reliable must be immune from doubt. From this he sorts his beliefs into categories and explains that if he finds even one problem or doubt in either of these categories then the whole set must be discounted. It is important to recognise here that Descartes’ form of doubt is unlike the typical doubt we exercise, but is rather known as ‘hyperbolic doubt’ (ibid.), meaning that he will reject on any grounds he finds to be dubitable. This strategy appears thorough enough for Descartes to be able ward off all unnecessary beliefs and make his way towards epistemic clarity.
In the first wave of doubt he brings his focus to empirical truths, being those which are gained from the senses. He realises that, at times, his senses have deceived him in the form of optical illusions or objects in the distance. Therefore it is uncertain to him whether he can know when to trust these perceptions. However Descartes only appears to reject a fragment of sense experience here, so he must now find a way to reject the entirety of empirical knowledge – specifically the knowledge which concerns our current state of sensory being, since Descartes was referring to past occurrences. This leads him to the second wave of doubt, known as the Dream Hypothesis. The thought experiment here forces us to consider whether we know for certain that we are not dreaming. Descartes asks how often his sleeping state does “persuade me of such ordinary things” (p.60), which leads him to suppose we don’t truly know what real life is since we cannot distinguish between dreaming and reality. With this Descartes is able to conclude that all ‘a posteriori’ knowledge cannot be validated or trusted, thus destroying the empirical foundation for knowledge. A criticism which can be drawn out here is that, in being able to claim that our dreams are sometimes replicas of waking life, one is presupposing the distinction – we cannot suppose our whole life is a dream since it would contradict with the very concept of a dream (Cardinal, 2006, pp.38-39). Although Descartes’ argument is not considering one is always dreaming as this problem suggests, he is still able to find doubt in his present state which he sought to do. The application of Descartes’ method of doubt here is therefore successful and straightforward in setting out arguments which refute empiricism, especially with the Dream Hypothesis which is more accessible to the meditator as an idea.
Now only left with ‘a priori’ knowledge, Descartes must test the validity of reason in order to complete his rigorous endeavour. Known as the Evil Genius hypothesis, he thinks of an omniscient, omnipotent but evil deity rather than a benevolent one – that this deity has purposely mislead him to believe certain truths about the physical world (which reason is concerned with). This is the ultimate sceptical argument for Descartes since he is a rationalist and believes in God (Skirry, n.d.), and so he will have to challenge these beliefs in accordance with the same scrutiny he applied to empiricism. Following from his hypothesis, Descartes realises that this deceit could be applied to all ‘a priori’ truths, such as that our ideas about shape, size, colour and mathematical truths exist at all (Frankfurt, 2009), leaving him in a state of diabolic doubt since there is now nothing which he can truly be certain of.
Following this state of epistemic jeopardy and massive scepticism from Meditations I, Descartes persists on his rigorous approach to find just one thing he can be certain of. He recognises that if he can find a way to defeat the Evil Genius problem then he will have reached his goal of finding a foundation which is unshakable to scepticism. Thus, he introduces the Cogito – an adaptation from his “Cogito Ergo Sum” featured in his ‘Discourse on Method’. Translating to “I think, I am”, the Cogito asserts that if one is in a position to doubt or be sceptical, then this itself proves their existence. The explanation for this claim is self-authenticating and innate to us, a necessary truth which we can use as a foundation for other claims we make. Moreover, the intuitive nature of it supports rationalist ideas, which is what Descartes also aimed to show. To answer the problem of the Evil Genius, therefore, Descartes implies that if he is being deceived by God then he must be existing – if he is able to think of such deceit then it must be necessarily true that he has a mind to be deceived. This undertakes a form of dualism, being the idea that our minds and bodies are completely separate. The realisation that knowledge is gained through the process of thinking from the Cogito provides the key foundation for all future epistemic pursuits, and marks the starting point for the power of reason over experience.
While the Cogito manages to assert something at this point in the Meditations, it is still accountable to some criticisms. For example, philosopher David Hume points out that thinking is in fact an experience, and thus the Cogito is no longer an ‘a priori’ truth but rather an ‘a posteriori’ one – we are just a collection of impressions (Hume, 1738). Although this doesn’t necessarily refute the idea of the Cogito, it still conflicts with Descartes initial aim to prove rationalism as the superior foundation for knowledge. Another criticism is by philosopher Bertrand Russell who points out that what the Cogito merely shows is “there are thoughts” (Russell, 1945). ‘I think’ also contributes to a circular argument – it assumes what it sets out to prove. The Cogito is arguably successful in appealing to one upon first glance – I cannot doubt that I am thinking because doubting is a form of thinking. However, one should be careful of how to interpret the certainty of this – if it’s just an intuition or if it’s a logical deduction which leads one to believe the conclusion. The trivial nature of the Cogito therefore doesn’t bring Descartes very far in his quest for knowledge, even despite his attempts to revive the credibility of reason in it.
Meditations I and II both set Descartes on a path in which he uses rigour to sift his way through all cases of pseudo-knowledge with his method of doubt. Quickly destroying the foundation for empirical knowledge, Descartes is able to move onto the more complex foundation being rationalism, with which he is espoused. Applying the same level of scrutiny to ‘a priori’ truths allows for a fair trial and doesn’t undermine its validity nor its invalidity. In effect, it brings to light the recurring problems such as the Evil Genius which, although difficult to resolve at times – leaving Descartes in states of utmost doubt, help him to further contemplate and challenge these perplex puzzles in order to progress in his epistemic pursuit for knowledge.