Descartes

Descartes

I think therefore I am , mind versus body, can I doubt everything? These are part of the legacy of French philosopher, Rene Descartes. He aimed to become to the modern world what the great Aristotle had been to the ancient. Did he achieve it?

Life

Descartes was born on March 31st 1596. He was a sickly child and spent much time in his own company, a fact which one can t help but imagine had a bearing both on his philosophical method and his ideas. Another philosopher-soldier (like Socrates before him), he enlisted in the army from 1617 and served until 1621, after which he devoted himself to philosophy and science.

During his philosophical career he hoped to provide a stable foundation on which to build scientific knowledge, trying to transplant the certainty of mathematics into the world of empirical investigation. This led him to write his two most remembered works, the Discourse on Method (the full title being the rather catchy: Discourse on the Method of Properly Conducting One s Reason and of Seeking the Truth in the Sciences) and theMeditations (or Meditations on the First Philosophy in Which the Existence of God and the Real Distinction Between the Soul and the Body of Man are Demonstrated). Whilst he also worked in the fields of, among others, Optics and Geometry, it is these two philosophical works that have secured his place in the history of ideas.

In 1648 he was engaged to tutor Queen Christina of Sweden in philosophy, but his old ill health and poor conditions lead to his death not long into the arrangement in 1650.

Ideas

Doubt

Science is based on evidence, right? And we obtain this evidence through the senses? So before we try to do any science, it would be worthwhile to clear the ground and find out just how reliable this sense evidence is . This is roughly where Descartes begins his scientific investigation. If you were going to erect a great scientific edifice, like Aristotle s, which would stand for the ages, you d first make sure the foundations were secure. For Descartes, this meant eliminating doubt from the the ground up. He wanted to take the kind of certainty you get with mathematics (2+2 always equals 4, the square root of 9 is always 3, and these things can be proved), and introduce that into the very roots of our knowledge.

The test of Descartes set to apply to all his knowledge was doubt. But to test every piece of knowledge to see if it could be trusted would be an endless task: are all swans white? does the sun revolve around the earth or visa-versa? do unsupported objects always fall to the ground? does water boil at 100 degrees Celsius? and so on and so on. Descartes, however comes up with a master-stroke to do away with the greatest volume of knowledge with the least effort. He resolved not to test all things to see if they could withstand our standard form of doubting, but to eliminate from his mind all beliefs that were even

susceptible to doubt. If there were any reason, no matter how small, for doubting a fact he would consider it false and unreliable. He says:

...if I wish to find anything certain and assured in the sciences, I must from now on check and suspend judgement on these opinions and refrain from giving them more credence than I would do to things which appeared to me manifestly false.

And so the stage is set for his next move to have the elegant destructive power needed to make his project feasible.

Have you ever seen someone at a distance and thought you recognized them, only to realize when close up that you were mistaken? Or have you ever walked into a room and jumped at seeing a figure out of the corner of your eye, only to realize its just a coat stand or something similar? Then your senses have played a trick on you, and proven you on these occasions to be false. So there is some doubt possible - but we can make the point more forcefully.

Isn t it true that sometimes when we see are dreaming we are completely convinced that what we are seeing, hearing, feeling, smelling, experiencing is real and actually happening? Haven t we all woken up and said to ourselves, oh, it was only a dream ? So is it not possible that we are dreaming now and only think we are where we are, as we are now? Descartes thinks so, and for him it provides room for doubt. And so he concludes that:

Everything I have learned up to now as being absolutely true and assured, I have learned from the senses. But I have sometimes found [as in the above cases] that these senses played me false, and it is prudent never to trust entirely those who have once deceived us.

The senses play us false and so cannot be trusted. Nothing the senses tell us is beyond doubt and useful in Descartes search for certainty. So is there anything that is immune to doubt?

Cogito Ergo Sum

Literally this means I think therefore I am , and has become something of catchphrase for Descartes philosophy. It s meaning must be understood in relation to the debate in the previous section: what can we know for certain, or, what is immune to doubt? Descartes answer is the Cogito (as it is sometimes called). After casting doubt on all sense data, which includes all knowledge of the external world or even about our bodies, because we only know these things through sense data, Descartes moves to the inner world. Is there any knowledge in our inner selves which is immune to doubt?

Even my name, personal details about myself are tainted with sense data. Where did I learn such details except through being told, or through seeing my image in a mirror etc? But there are some objective things I know even without the senses, mathematics for instance. I can do sums in my head and they always turn out the same, 1+1=2 and things like that. No sense data is involved in maths so the results of my mathematical calculations can t be doubted. But like some diabolical lawyer, Descartes must find a way to cast doubt even on these truths. Let us suppose that:

...there is, not a true God, who is the sovereign source of truth, but some evil demon, no less cunning and deceiving than powerful, who has used all his artifice to deceive me.

As well as putting the final nail in the coffin of our sense data (because all we see and experience could be just some picture show this deceiving demon puts in our heads), this also allows us to doubt mathematical knowledge. If there were such a demon I couldn t be sure that, every time I made a calculation, he wasn t perverting my results and convincing me that I was coming to the same correct conclusion each time. So even mathematics is conceivably doubtable.

Now it is important to stress that Descartes does not want to say that any of these things are true, or even likely. He is only carrying out his project of testing knowledge claims, trying to find if there are any that it is inconceivable to doubt, that is, indubitable on any grounds imaginable.

So, given the deceiving demon argument, it seems that all inner knowledge too is conceivably open to doubt. All the images in our mind may be only false sense date, all our reasonings could be being perverted without our realizing it, and so the content all our thoughts are open to doubt. But that I am having thoughts, whether they are true or false cannot be doubted. There is something that is thinking thoughts, this no demon could deceive me about - I think/have thoughts, therefore I can be sure that I am/I exist. Cogito ergo sum, as Descartes puts it. This is the indubitable piece of knowledge Descartes was looking for, and on this he will try to build farther reaching and more stable knowledge claims about himself, the world and even certain theological statements.

Next, I examined attentively what I was...

The last central theme in Descartes philosophy we must explore is his ideas about the human person - specifically the mind/body distinction. After arriving at the Cogito ( I think therefore I am ) Descartes begins to draw conclusions about the nature of the I involved. First, it must be a thinking thing. I am a thing that can be characterized by my having thoughts, I am a mind. And even stronger than that, as I can imagine this mind without an attendant body, my mind must be separate from the body. In fact for Descartes the mind is easier to know than the body , as experience of the mind is immediate and certain, whereas experience of the body is mediated by the senses, and is at least doubtable.

So Descartes has separated out two substances , that is stuffs : there is mind, which is a thinking and non-extended thing ( non-extended meaning it takes up no space) and there is body, which is non-thinking and extended (i.e. takes up space). But if Descartes is going to push forward his main project of doing science, he had better make an attempt to rescue the class of extended things, as these are the whole subject matter of science. After all, what kind of science would we have if we couldn t talk with certainty about tables and chairs and human bodies, let alone atoms, quarks and leptons etc.

Descartes attempts to secure the existence of the body, and all other extended things, by introducing a guarantor: God. Now he may have lost some of us at this point, but consider the more religious age in which he worked, and bear with us. It constantly appears to us that we have bodies and that there are extended things around us. Well if we take into account that we were created by God, (a good God, perfect and not able to contradict himself), we must be able to rely on what we perceive about such things, as God would

not set up our whole self-image, and our image of the world (as extended, physical) on a lie.

One may object at this point and remind Descartes of his deceiving demon. How can he now do away with him and throw himself instead on God s honesty? Well, starting from the notion that thoughts exist (as he is himself a thinking thing), he note the existence of thoughts of perfection. The idea of a perfect, infinite being is so different from himself (a finite, imperfect thinking thing) that it could not have originated in himself. So it must have its origin in something objective. Also, he could not have come into being except by the action of something more perfect. This perfect thing is God.(In case you didn t notice, Descartes has just proved the existence of God!) And as perfect it must be good, reliable, honest and not deceiving. So we can trust that such a creator would not set me up to be deceived in the way we could imagine the demon doing. So we can trust our clear perception of having a body, and there being an external word.

So, God guarantees that our perception of having a body are true. What then is the relationship between these two substances, mind and body? They are in themselves separable and can exist apart, but in actual fact they form a very close union. My mind reacts to the stimulus of the body. If the body is hurt I experience mental sensations of pain, when the body is hungry I experience in my mind the sensation of hunger. If body and mind were not so intimately tied together then:

...I who am nothing but a thinking thing, would not feel pain when the body was hurt, but would perceive the damage purely by the intellect, just as a sailor perceives by sight if anything in his ship is broken.

I am in myself a thinking thing, in very close un ion with a body.

Roundup

Some of Descartes arguments may seem rather odd to us today, in fact they seemed like that to some in his own. But nevertheless his conception and the scope of his thought must strike one as impressive. Whether he proved successful in his attempt to find certainty is open to debate, and it must be said that Descartes is somewhat out of fashion today. But in my opinion, despite having to be a bit careful with him, Descartes rewards those who read him with an open mind, that is without hostility or prejudgement.

Further Reading

Descartes two classic texts can be found in one volume in:
- Rene Descartes, Discourse on Method and The Meditations, Penguin, 2007.

The Meditations are an especially good read, and like I have said, impressive for its scope. A good critical introduction is:

- John Cottingham, Descartes, Phoenix, 1997.

Cottingham is not shy about taking Descartes to task on his arguments, and the validity of his conclusions derived thereby. A more in-depth study is:

- Gary Hatfield, Routledge Philosophy Guidebook to Descartes and the Meditations , Routledge, 2002.