by Melvyn Bragg
AMIRA K. BENNISON: And, of course, he chooses to spend the rest of his life in Ghazna, so he seems to have become reconciled to being there and to becoming a much more prominent court intellectual rather than the figure in the background that he is with Mahmud.
He wrote a book of instruction for his patron, the Canon of Mas’ud, a re-writing of the Almagest of Ptolemy, which had been the most important work of astronomy in the classical period both in late Greek antiquity and Islamic culture.
JAMES MONTGOMERY: Al-Biruni sets out to provide the new ruler with a comprehensive guide to the structure of the universe, the movement of the planets, together with a number of his own observations. Some historians of mathematics, for example, have seen, in one or two of Al-Biruni’s calculations, anticipations of functional relationships.
He certainly anticipated later discoveries, yet his immediate legacy in the Muslim world was very small, Hugh Kennedy suggested, with no direct connection to what came after. There is only one significant manuscript of The India, so his reputation survived by a narrow thread.
HUGH KENNEDY: It appears again in the Ottoman period and was taken up by nineteenth-century European intellectuals and, in the twentieth century, by Muslims, particularly in Iran, because he is considered to be an Iranian. But nobody seems to have read his book very much, nobody took the research any further. It is a bit of a shooting star.
With what we know now, it is clear that Al-Biruni had a very brilliant and very flexible mind. He was very inquisitive, and his interest in the natural world was enormous.
AMIRA K. BENNISON: He did write about minerals, he wrote a book on pharmacy and, in that, he lists all the different herbs and plants you can use and gave their names in five different languages, which is a remarkable achievement. In total, about twenty different dialects and languages are employed in the work. He was a hugely intelligent man.
COGITO ERGO SUM
There are few sentences in the history of philosophy that have become as famous as their authors. ‘The unexamined life is not worth living,’ said Socrates, reputedly, in the fifth century BC. ‘Man is born free,’ wrote Rousseau, two millennia later, ‘but everywhere he is in chains.’ Pithier still is Nietzsche’s statement, ‘God is dead.’ But perhaps the best-known saying in the history of philosophy is one usually quoted in Latin, cogito ergo sum – ‘I think therefore I am.’ This statement first appeared in 1637 in a work by the French philosopher René Descartes. Despite its simplicity, it is the starting point for an entire system of thought; today, Descartes’ ‘cogito’ argument is commonly regarded as one of the foundations of modern philosophy. What does this apparently unassuming sentence mean, and why does it still provoke criticism and comment, almost 400 years after it was written?
René Descartes.
With Melvyn to discuss Descartes and his statement ‘cogito ergo sum’ were: Susan James, professor of philosophy at Birkbeck, University of London; John Cottingham, professor emeritus of philosophy at the University of Reading, professor of philosophy of religion at the University of Roehampton and honorary fellow of St John’s College, Oxford; and Stephen Mulhall, professor of philosophy at the University of Oxford.
Descartes first used this short phrase in passing, in the work that he published in 1637 called The Discourse on the Method of Rightly Conducting One’s Reason and of Seeking the Truth in the Sciences, to which Melvyn referred above, and which Descartes wrote in French.
SUSAN JAMES: There he wrote, ‘Je pense, donc je suis.’ That was translated into Latin as ‘cogito ergo sum’ – I think therefore I am. This is the origin of this phrase, and there Descartes presents it as what he calls the first principle of philosophy, the first metaphysical principle of philosophy.
It was not until 1641, in The Meditations, that he began to spell out the argument he was summarising there, which the programme explored.
Descartes was born in Tours, France, in 1596 and he went to the Jesuit College of La Flèche, which provided a very sound and solid education with Latin and Greek and rhetoric, mathematics and philosophy.
SUSAN JAMES: After he had finished school, he went to study law at the University of Poitiers briefly because, in spite of his father’s wish that he should become a lawyer, he went off to be a soldier. In Holland, where he joined an army, he came into contact with a famous mathematician, Beeckman, and began to produce really original and creative work in geometry and algebra.
This was the beginning of Descartes’ intellectual project, a fascination with the clear method that he was to develop for solving mathematical problems, and that became a more ambitious explanatory system for the whole of nature.
In his education, he would have imbibed the dominant system, scholasticism, which had been going strong for several centuries. This was based on the principles of Aristotle, elaborated so as to be consistent with the Bible and with Christian doctrine.
JOHN COTTINGHAM: One of the most important [features] was that each subject was, in a sense, separate, it had its own methods and standards of precision, as Aristotle himself originally said. It was also qualitative – that’s to say, things were explained, things behaved the way they did because of certain real qualities they possessed. For example, things fell to the ground because of the quality of gravitas or heaviness.
Although this was the system in which Descartes was educated, he thought that this approach was not really valuable as an explanation of natural phenomena.
JOHN COTTINGHAM: Instead, you ought to look for quantitative explanations, that things behaved the way they did because of their size and shape and motion. The scholastic system was largely purposive; things were explained as moving towards a goal, or purpose. Again, Descartes reacted against this, and thought instead that we should search for mechanical explanations.
This was an inspiring time for Descartes, with so many developments in the understanding of the natural world. While Descartes was still at school, Galileo’s discoveries of the moons of Jupiter had been published. These were the first clear experimental confirmations that earth was not the centre of the universe, and confirmed the Copernican view from a few decades before Descartes was born.
Descartes also drew inspiration not from others, but from three powerful dreams he had in November 1619, when he was twenty-three and travelling as a gentleman soldier in southern Germany.
JOHN COTTINGHAM: [He] spent the whole day shut up in a stove-heated room, and he had three very vivid dreams. The first one involved a hurricane, which pushed him around and frightened him severely. He took refuge in a chapel and met someone who presented him with a fruit, which he thought was a melon from a foreign country. The second dream was very quick, it involved a thunder clap and sparks. In the third dream, there was a series of books. There was a Latin poem that begins with the line, ‘What path in life shall I follow?’ Then a motto of Pythagoras appeared; then, finally, an unfinished encyclopaedia, which he took to represent all the sciences connected together.
One of the things that Descartes drew from these dreams was the idea of the essential unity, or continuity, of human knowledge. In certain contexts, he famously used the image of the tree of human knowledge with metaphysics, first philosophy, as the roots, then physics as the trunk and all the other sciences as the branches.
STEPHEN MULHALL: On the one hand, he seems to think that there is a fundamental unity in the whole system of human knowledge, and so it must be possible in principle to articulate those various bodies of knowledge as forming part of a fundamental unity. And yet there is a certain kind of hierarchy built into that image. Physics gets a certain kind of priority in relation to the other natural sciences and, in turn, metaphysics, first philosophy, has a certain priority over physics.
Descartes was committing himself to that project, to explore a certain kind of unity of human knowledge, and perhaps this is what he interpreted from the image of the encyclopaedia in the third dream.
There was another aspect of this context that was fundamental to his
sense of how to go about developing that project. If first philosophy, or metaphysics, was the root of the whole enterprise, then one needed some way of establishing genuinely reliable knowledge to feed into that.
STEPHEN MULHALL: The reliability of that knowledge can then be transmitted through the rest of the edifice, if you like. The method that Descartes uses is that of scepticism, a kind of methodical doubt.
The centre of this plate depicts Descartes’ system of the universe.
This was not just a radical break with Aristotelian ways of understanding nature, it was one that revealed that the vision of the world, which is delivered to us naturally through the senses, is fundamentally unreliable.
In 1637, Descartes had produced The Discourse on the Method, mentioned earlier, a conception of method that he cleaved to throughout his intellectual career. There were four aspects to these, and the second, third and fourth had to do with principles: that one should break down the areas that one tries to study into the simplest possible parts; that one should build from the simple to the complex; and that one should try to make sure that the chain of reasoning, from the simple to the complex, is as comprehensive as possible.
STEPHEN MULHALL: The first principle is the one that turns out to be much more fruitful, and radical, than it might look. According to the first rule of this method, Descartes says that one should only rely upon that which one clearly and distinctly perceives to be true, and that turns out to be the core of the method that gets much more systematically articulated in The Meditations.
The ‘cogito’ argument, Susan James continued, was something that Descartes adapted from Augustine and, in its simplest form, it is the idea that, when you are thinking something, when you are doubting something, you know that you are doubting it. It was later, in the context of The Meditations, that he explained what use he was going to make of this claim.
JOHN COTTINGHAM: To find something stable and secure, you have to demolish the whole lot and start again right from the foundations, that’s what he says in the opening of the first meditation. There are six meditations, perhaps modelled on the spiritual exercises of the Jesuits who brought him up. And it starts with these waves of doubt, you push doubt to the limit to see if anything survives. He starts by doubting the senses, our basic source of knowledge, the five senses.
Descartes mentioned the stick in water that looks bent but is actually straight, or the sun and the moon, which look roughly the same size to people on earth even though the sun is enormously bigger. Then, he said, here he was, sitting by the fire in his winter dressing gown, surely that was so certain that he could not be wrong? He reasoned no, that was not certain, because sometimes he had vivid dreams and thought that something like this was going on, only to wake and find he had been asleep in bed.
JOHN COTTINGHAM: Then he broadens the doubt to think: maybe the whole of life might be a dream, maybe the whole external world, all the images are just beamed into my mind by a malicious demon, bent on deceiving me. Then he comes out of that into certainty because he reasons: even if I am being deceived, even if I am doubting, I must still be here in some sense to do the doubting. So I, at least, must exist. So, as he phrases it in The Meditations: ‘sum, existo’ – I am, I exist.
The ‘cogito’ argument was meant to serve the purpose of finding something that was not doubtful, but this was, Susan James suggested, a very small Archimedean point with which to move the world. What Descartes could be sure of was only that, as he was having a thought, he knew he was having it.
SUSAN JAMES: As I am remembering that I was walking down the street, I know that I am having this thought of remembering myself walking down the street. Of course, I don’t know whether it is true that I was walking down the street. As long as I am thinking some thought or other, then I know that I exist. But it seems that, at this stage, all I know about myself, at the most, is that I’m this succession of momentary thoughts.
In Stephen Mulhall’s view, there is a certain kind of performative aspect to the argument (if it is an argument) that is being presented. The force of the conclusion is only going to have an impact on us in so far as we are actually engaged in the process of reflection that delivers that conclusion. This connects with a bigger issue, which is that ‘cogito ergo sum’ would have looked like a very peculiar kind of argument at the time Descartes put it forward.
STEPHEN MULHALL: The canonical example that philosophers always offer of argument structure involves Socrates: ‘All men are mortal, Socrates is a man; therefore Socrates is mortal.’ You only get to the conclusion because you have two premises from which the conclusion follows. When someone tells you ‘cogito ergo sum’, you naturally start looking for what the premises might be and, usually, at least in the form of a syllogistic argument, one premise isn’t enough.
To his objectors, Susan James explained, Descartes would reply that this was not really the way he wanted one to take the argument. The order of discovery is that you perceive with a simple intuition of the mind, ‘I am, I exist,’ and that is how you get started. In fact, John Cottingham added, Descartes said in his introduction that he did not want to have anything to do with those who were unprepared to follow him along this path and meditate for themselves.
Descartes had to get out of this tiny flickering candle of subjective certainty to a whole system of knowledge, and this was where God came in.
JOHN COTTINGHAM: Once he is aware of himself as existing, he is immediately aware of his imperfection of himself as finite. There are many things he doesn’t know, there are many things he can’t do. And yet he has a sense of something infinitely greater than himself. He has the idea of this infinite being, and this idea, he reasons, couldn’t have been created by him, from his own resources, and therefore must have been put in his mind by God, as he puts it, ‘like the mark of the craftsman stamped on his work’.
Once God was in the picture, Descartes had something good and benevolent, and he could then reason that his mind was a reliable instrument and he could get going and build his new system of science.
Once Descartes had this distinct idea of the mind as something that existed, he could begin to explore it. One of the ideas he found was that of physical bodies.
SUSAN JAMES: He says, ‘What I do know about a body, for sure, is that, in order to be a body, it must have certain essential properties,’ which Descartes calls ‘extension’ or ‘extendedness’. Roughly speaking, it must have shape and size. He has got two clear and distinct ideas, one of his mind as something fundamentally thinking, the other of his body as fundamentally extended.
From this, he argued he was in a position to see that the mind and body are distinct and that there is nothing in his idea of a mind that depends on his idea of a body, and there is nothing in his idea of a body that depends on the existence of a mind.
SUSAN JAMES: Now he has done something quite dramatic really, which is that he has generated a quantifiable conception of body that can be the basis of physical science, and a quite separate idea of a mind, which is just something that thinks. This is against a background of an Aristotelian notion of a mind or soul, which has all sorts of capacities other than thinking.
In The Meditations, this sense of a fundamental essential distinctness between mind and body came out of the application of the method of sceptical doubt. There is also a way in which this sense of mind and body fitted into a broader cultural context, particularly in theology.
STEPHEN MULHALL: What it suggests is that, if the mind is essentially immaterial, a belief in the immortality of the soul is entirely consistent with the basic principles of first philosophy. Matter is the kind of thing that decays and decomposes, because it is extended, it is divisible. Something that is essentially non-material is indivisible, so what you get is a conception of the mind that is entirely constant with the conception of the soul as being of the essence of the human individual.
There was concern among other philosophers about what became known as the Cartesian circle, which went
back to the question of the function of God in the system, as presented in The Meditations. There, God gave a reason to treat not just our senses but also our reason as generally reliable.
STEPHEN MULHALL: The worry, that is encompassed in the idea of there being something circular here, is on what basis do we believe in God’s existence, if not the fact that we clearly and distinctly perceive the truth of the arguments that Descartes offers for that belief? But it is God who is supposed to underwrite the validity of that general criterion for truthfulness.
Another way of putting this, John Cottingham added, was an earlier formulation in Descartes’ Rules for the Direction of the Mind, which was ‘sum ergo deus est’ – I am therefore God exists. It looked as though the whole thing was a vicious circle.
Hobbes was one of the people whom Descartes invited to write objections to The Meditations and Descartes replied to them. Hobbes was a materialist and picked Descartes up on the ‘cogito’ argument in particular, and raised the question of what this ‘I’ was that was doing the thinking, which Descartes said was the mind.
SUSAN JAMES: Hobbes says, ‘You say it is mind, but how can you be sure that’s all it is, maybe it is also a body.’ Hobbes seems to think that it must be a body, because only bodies can be the subjects that are capable of having thoughts predicated of them. Descartes points out, quite reasonably, that Hobbes is begging the question there. But there is a problem, which is what exactly this ‘cogito’ argument establishes about who this ‘I’ is.
As the centuries rolled on, John Cottingham said, there was a lot of emphasis on subjectivity; the movement we know as existentialism laid a lot of stress on the individual awareness of the subject, and the idea that the subject had to construct reality from him or herself. That was Descartes’ starting point so, in a sense, the existentialists were inheriting that point of the individual existing self and starting philosophy from there.
