At the opening of his first meditation, Descartes asserted the need to “demolish everything completely and start again right from the foundations.” This was known as Descartes ‘Mehodological Doubt.’ Descartes' aim, however, is not that of "the sceptics, who doubt only for the sake of doubting," but instead "to reach certainty.” He used the example of a ‘basket of apples,’ to show how one can claim indubitable knowledge. Descartes said that you examine all human knowledge to see if it can be doubted. If it is dubitable, then it is “infected,” thus it must be mercilessly rejected as flawed. Any apple of knowledge that is finally left behind after this procedure would obviously be very special. It would be the real thing – guaranteed, indubitable knowledge. Like the philosopher Bernard Williams says in the book of ‘The Great Philosophers’ – “it’s like having a barrel of apples, and some of them are bad and some of them are sound, and you wasn’t to separate out the sound ones.” Hence, Descartes used his ‘Methodological Doubt’ to remove any of his beliefs that could be in doubt so as to find indubitable knowledge. Bryan Magee on his book on ‘The Great Philosophers,’ states that “doubt – is to find rock-hard, indubitable propositions, which can then function as the premises for arguments, thus providing unshakeable foundations on which an edifice of knowledge can be built upon.” Although as Bernard William says in ‘The Great Philosophers’ – “Descartes never meant for his philosophical doubt to be a tool for everyday living.” Thus, Descartes thought that as he could not systematically doubt everything, he could solve this problem by asking himself where all human knowledge comes from, which for him were our senses and our reason. However, as our senses can be doubt like seeing something far away looks different from seeing something close-up, and that even mathematics and logic can be doubted in the end, he thought there must be an evil demon continuously hypnotizing us to believe false claims. Thus for a brief moment Descartes nearly convinces us that the apple basket of knowledge must remain empty. Although, by going through this process of continuous doubt, Descartes eventually discovered the fact that he was thinking in order to doubt, and thinking cannot just happen in mid-air. There has to be a conscious or mind doing it, so Descartes cannot doubt that he exists either, for he is thinking i.e. ‘Cogito ergo Sum.’ As John Cottingham says in his book on ‘Descartes’ – “Probably the best known fact about Descartes’ philosophy is that its starting point is the realisation ‘I am thinking, therefore I exist’ … what guarantees the certainty of ‘I exist’ is, Descartes suggests, a process of thought, the proposition ‘I exist’ is true whenever it is conceived in the mind.” Hence, the significance of the discovery for Descartes’ overall project is twofold. First, the knowledge of his own existence is not something he has noticed, or something he has been taught, but something he has worked out for himself – something so obvious that it must be true. It is therefore an example of the kind of God-like rational understanding that enables men of science like Kepler and Galileo not merely to observe the way the world looks but to work out rationally how it must really be. Secondly, the Cogito also enshrines Descartes belief in the uniqueness of the human mind because he can prove his own existence even when he is assuming that the entire world around him is an illusion, he claims this shows that he himself, his own thinking soul, is not a part of that world, but a separate existent. The Cogito was an extraordinary discovery, and as the first principle of all of Descartes’ work, had also influenced all kinds of modern philosophy i.e. Jean-Paul Sartre (1905-80) founded his version of Existentialist philosophy on it. Sartre thought that the Cogito was not so perfect – “It’s certainly not as ‘clear and distinct’ as Descartes thought it was because it’s not clear that we are directly aware of ourselves in the way he says we are.” Although, as Sartre may not have found the Cogito entirely perfect, it still remains one of the most important discoveries of Western Philosophy, and may be said to mark the spot of where Modern Philosophy begins and Scholasticism ends.
However, the Cogito had seemed to be a slight dead end as even though you may know for sure that you exist at that exact moment when you are thinking or doubting, only proved to Descartes that your mind exists but not anything else exists outside of yourself. Thus, this kind of private knowledge was of limited use. So, Descartes thought it necessary to change this private temporary knowledge into something that would be more public and permanent. He thought that if he could find what made the Cogito so certain, then he would be able to unveil a universal rule that would offer alike guarantees of certainty about other kinds of knowledge. Hence, Descartes thought that there must be a “method,” which would organise the human search for knowledge more systematic, and successful. The ‘Discourse on Method,’ carefully itemises all the ‘Rules for the Direction of the Mind’ that need to be followed if scientific investigation is to be more than a haphazard mixture of intuition and guesswork. This is where Descartes attempts to show how it is possible to discover true knowledge just by using a few central procedural rules. He thought that these rules could be the basis for a new kind of scientific logic. The rules for Descartes ‘Discourse on Method’ are as follows; “we should not accept as true proposition, which it is possible to doubt” – The feature of a proposition, which makes it impossible to doubt is that it is ‘clearly and distinctly’ shown to the mind. He adopted the idea that anything clearly and distinctly ‘perceived’ is true and later the same for ‘conceived.’ (By ‘clear,’ Descartes meant that ideas in the mind must be as obvious and apparent to us as physical objects that we see with our eyes). He claimed that there are two mental operations by which one can claim certain knowledge. They are intuition and deduction. Intuition is a faculty of reasoning independent of the sense and imagination (an intuitive proposition is known as ‘a priori’). Deduction is a process where by propositions are logically derived from other propositions. He thought that if deduction is to succeed then the initial propositions must be obtained by intuition. Descartes second rule was to “divide the problem into as many parts as needed,” which is the analysis of his method. His third rule was to “argue from the simple to the complex” - this was the synthesis. Descartes saw the second and third rule as that if you have a complex proposition, the first stage is to analyse it into smaller parts, until you reach propositions that are so clear and simple that they can be known as intuition, which can thus prove the initial proposition. His fourth and final rule for his ‘Discourse on Method’ was to “check ones argument” - that is to check everything carefully once you have finished the procedure of obtaining indubitable knowledge of the world. Hence, for Descartes, knowledge had to be logically deduced. We can see from his ‘Discourse on Method’ that Descartes is an example of rationalism in the most extreme form, claiming all human knowledge is derivable from ‘a priori’ reasoning. Thus, given that Descartes held such ideas to be innate, follows he was claiming that all we can know for certain may be discovered by working out the logical implications of what we think to be known as true.
Although, before Descartes could rely on the “clear and distinct” rule, he needed to get rid off the evil demon that he thought was constantly deceiving him. Thus, he had to set out to prove that a God, who will never deceive us, and would guarantee any “clear and distinct” ideas that entered our minds, would be true, to exist. As Cottingham says in his book on “Descartes,” which states that “the ‘true God, in whom all the treasures of wisdom and the sciences lie hid’…” So, he begins by stating that ‘he already has a “clear and distinct” idea of God in his mind. Therefore, something must have caused this idea to be in his mind. A cause must have as much reality as its effect. Ideas like this one do not come from nowhere. So, God must exist.’ Descartes argument is known often as the ‘Trademark Argument’ - Descartes states that “when God makes us, He stamps the innate idea of Himself into our minds.” Descartes relies on the old Scholastic “Causal Adequacy Principle” to reinforce his claim. He says that ‘causes must be as real as their effects and reality is a matter of degree, so that some things are “more real” than others. Also, things that physically exist are “more real” than ideas in the mind. The cause of the idea of God must therefore be more real than the idea itself. So, therefore God must exist.’ An objection was made to Descartes’ second argument that was put forward by John Cottingham, which was presented in his book on ‘Descartes’ – the ‘Trademark Argument,’ “was in effect, a version of the second of Aquinas’ celebrated ‘Five ways’ of proving God’s existence: viz. the argument that the series of causes in the world must ultimately lead to an uncaused cause.” However, Descartes objected to this claim, by stating that “in inquiring what caused me, I was not simply asking about myself as a thinking thing; principally and most importantly I was thinking about myself in so far as I observe amongst other thoughts, that there is within me the idea of a supremely perfect being … This idea shows me not just that I have a cause, but that this cause contains every perfection and hence that it is God.” The philosopher Bernard Williams comments on Descartes ‘Trademark Argument,’ stating that “it relies on a supposedly necessary principle to the effect that the lesser cannot give rise to, or be the cause of, the greater. Descartes is sure that he has an idea of God, and that idea is the idea of an infinite thing. Although, in itself it’s only an idea, the fact that it is the idea of an infinite thing demands on a very special explanation. Descartes claims that no finite creature as he knows himself to be, could possibly have given rise to such an idea, the idea of an infinite being. It could have been implanted in him only by God himself.” Thus, Descartes argument is now infamous for being the ‘Cartesian Circle.’ Descartes uses that which he wishes to prove as one of his premises. You can not guarantee the ‘clear and distinct’ rule with a truth-telling Deity if you have already claimed that you know He exists as you have a clear and distinct idea of him in your mind. Descartes needed God to guarantee his rule and the rule to guarantee that God exists. Thus, his ‘Cartesian Circle’ states that “God exists. He guarantees the ‘clear and distinct’ idea rule. I clearly and distinctly perceive that God exists. God exists…” etc. However, as John Cottingham said in his book on “Descartes” – “Since it has already been argued that the first version of the ‘Trademark Argument’ fails, and since the second version must fail to carry conviction if the first version is rejected, it will therefore be best to proceed without more ado to the entirely distinct and separate argument, which Descartes offers later on in the Fifth meditation; this is an argument which has nothing to do with causal considerations, but is based on a purely ‘a priori’ analysis of the concept of God.” Therefore, Descartes produced his own variation of another old scholastic argument for the existence of God, known as the ‘Ontological’ argument. The theologian, St. Anselm (1033-1109) is usually given the credit for inventing it. The Ontological argument states that “God is a totally perfect being. Total perfection must involve existence as ideas are inferior to things that exist and if God is perfect, he can not be a more inferior idea. Therefore God exists.” Descartes’ Ontological Argument is a little different. His ‘clear and distinct’ idea of God is of a totally perfect being, so God must be totally perfect, and as total perfection must involve existence, then God must therefore exist. Although, if knowledge has to be appropriated by the mind and not of the senses, what kind of guarantee can we have that we are not thinking absolute nonsense? Descartes’ answer to this problem is that God has created eternal truths about us and the world that, if we perceive them as ‘clear and distinct,’ then they are guaranteed. Therefore, as Bernard Williams says in Bryan Magee’s book on ‘The Great Philosophers’ thus “through the help of God, we put the world back again … we come to the conclusion that not only is there an external world but that just as thought is my essence as a thinking thing, so the external world too has an essence and that is simply extension.”
Although, another concern for Descartes was that if God guarantees ‘clear and distinct’ ideas, then why is it that conscientious people still make mistakes? The philosopher, Benendictus de Spinoza (1632-77), believed that human ability is virtually infinite in capacity. However, Descartes was more pessimistic as for him; ‘the human mind will always be finite and capable of error. Only God can have this kind of infinite mental capacity.’ Descartes had a theory about why the human mind would always be of limited ability. His theory is as follows: “We come to believe or make judgements about things after exercising two of our faculties – our intellect and our free-will. Our minds may decide that the angles of a triangle add up to 180 degrees but then we have to choose to believe that this is so. Provided we always choose ‘clear and distinct’ ideas, then, according to Descartes, we cannot make mistakes.” Therefore, with this explanation, Descartes has been able to hold on to his doctrine of divinely certified ‘clear and distinct’ ideas, and at the same time to explain why human beings get things wrong.
Baruch Spinoza was enormously impressed by Descartes’ belief that the task of science was to see beyond the world as it appears to the uneducated person in the street, and as it had been described by traditional learning, to an underlying reality, which was not describable of our day-to-day experience of it. However, he wanted to go beyond Descartes in two crucial areas. Firstly he held that Descartes’ belief that the human soul was something wholly outside the natural order was absurd, and would make it impossible for us ever to give an objective, scientific account of the place of human beings in the world and of the best way for them to live their lives. Secondly, he thought that Descartes’ belief in a traditional Christian God meant that he would never be able to reconcile the life of science and the life of religion. The history of European thought since Descartes’ day suggests that Spinoza was right on both count; but his own attempt to resolve those problems proved much too radical, and his ideas were generally despised both in his own lifetime and after. However, one thing that Descartes, Spinoza, and also of the philosopher Leibniz, had in common was their desire to look beyond the world of experience, their willingness to say that despite all appearances, the world is not as it seems: it is a spatial continuum with immaterial souls, a timeless psycho-physical totality, it is an infinity of interlocking perspectives.
In the conclusion, Descartes made a large impact of Epistemology, as he did not rely on others teaching to assist him in his search for indubitable knowledge. He founded the ‘Cogito ergo Sum’ – which managed to show that he could be certain that whenever he was thinking or doubting, he was thus at the same moment existing too. Descartes also managed to prove the existence of God, through various arguments, such as the ‘Trademark’ and ‘Ontological’ argument. Other philosophers prior to him, like Aristotle and Aquinas, were also in search for certain knowledge, although, Descartes, discovered, how to find indubitable knowledge of the world, simply by his ‘clear and distinct’ rule, and by confirming this rule by the existence of God. Thus, forming his infamous ‘Cartesian Circle.’ Descartes inspired and influenced other philosophers, such as Baruch Spinoza.
