Thought Itself

For this lecture, read parts 1 – 3 of Descartes’ Discourse on Method.

RENE DESCARTES (1596-1650), known as the first great modern European philosopher, wrote the first canonical modern European philosophy texts, his Discourse on Method and his Meditations.  He is also known in mathematics for the Cartesian coordinate system (X and Y as two dimensions), a device useful for visually displaying algebraic equations and critical for the later European development of calculus by Newton and Leibniz.  The word Cartesian is used, rather than Decartesian, to refer to things that are of or like Descartes, such as his followers, the Cartesians, his coordinate system and his dualism between body and mind.

Descartes was born in Touraine, France, a town which has since been renamed Descartes after its most famous citizen.  Descartes’ father was a member of parliament, though his mother died when he was very young.  He went to law school to follow his father and become a merchant, but decided to become a mercenary instead and fight in the 30 Years War “to seek truth“, in his words.  It seems that he did not find truth in law school.  As a soldier, he had much time waiting for battle, and studied mathematics and science in his spare time.  On the night of November 10th, 1619, Descartes had a series of visions that convinced him that the world is a rational and mechanical system profoundly in tune with the rationality of the human mind.  Note that, before Europe received much of basic mechanics from China and algebra from Muslims, Descartes would have little reason to view nature as a mathematical machine.

At first, Descartes intended on writing a book on physics, his Treatise on the World, but in 1633 Galileo was condemned by the Catholic Church for his theory that the earth moves around the sun, a theory that posits the sun at the center of the solar system and universe instead of the earth.  Because of Galileo’s troubles, Descartes decided to publish his Discourse on Method instead, and it is today considered the first major work of modern European philosophy.

This caution did not spare Descartes however, as the work was condemned by the Pope in 1663, thirty years after Galileo’s work was condemned and after Descartes’ death, and it was put on the prohibited index of books alongside many others that are foundational for the European Enlightenment. Even though Descartes, like Aquinas, argued that reason teaches us that the Catholic Church is the one true religion, his heresy was teaching that it is reason that shows us this, not the authority of the Church or its connection to objectivity itself.  Descartes remained a practicing Catholic until his death.

As the skeptical philosopher of science Feyerabend notes, the Church did not merely stand for ignorance, but supported the philosophers and scientists whose work did not conflict with its dogmas, as do institutions in general.  As far as the Church was concerned, it was the work of Descartes and Galileo that was in conflict with reason and experience already acquired, matters of debate for centuries between philosophers and theologians within the institution.  If one assumes that the Bible is an authentic record of human experience, and if it appeals to human reason in telling everyone to seek the light and be critical of humanity, it is not difficult to assume that Descartes and Galileo are in contradiction with the science of their day, supported by the institution of the Church, the highest science of the time being theology.  According to Feyerabend, Galileo looked through a telescope and saw some things that contradicted Church dogma, but missed other things he could have seen that later scientists would explore.

Descartes’ death is famous and unfortunately funny.  For the majority of his life, he worked in bed until noon each day, an aristocrat who had the time and leisure to do this.  After he became famous and his works were prohibited by the Catholic Church, the Protestant Queen Christina of Sweden invited him to Stockholm to be her private tutor.  Unfortunately for Descartes, she wanted lessons each and every morning at five o’clock.  Between the snow and the early mornings, Descartes was soon sick with pneumonia, and died.  Maybe we should all work on our problems every day until noon, safe in bed.  This is similar to Sir Francis Bacon’s famous death, catching pneumonia after repeatedly stuffing snow into chickens to try to preserve the meat and keep it from rotting.  Some Swedes reported that Descartes was killed with a poisoned communion wafer given to him by a priest but the sources on this are questionable and it is likely this story was invented by Swedish protestants.

Descartes’ philosophical writings, particularly the Meditations, drew the reactions of several philosophers who themselves went on to become famous, particularly Spinoza, Hobbes, Hume, Leibniz, and Locke.  In the Meditations, Descartes asks: What we can know for certain if it is possible that everything is an illusion of the mind?  Like Avicenna, Descartes concludes that we can be certain that we are aware and conscious.  From this, he proceeds to conclude that we can be certain that our thoughts are our own, that there is a good and loving monotheistic god who would not deceive us about these things, and thus that the world is real, that there are things in the world that we can know for certain.  Some philosophers agreed with this very much, but did not find Descartes’ argument convincing and tried to come up with more satisfying proofs. Other philosophers who were more skeptical did not buy it and argued that human certainty is gathered through experience, not simply known mathematically via pure reason.  These two sides of the debate became known as Rationalism and Empiricism.

In a world of increasing algebra and mechanics, Descartes turns from an ancient understanding of causes up in the heavens above, acquired through centuries of charting the stars and the seasons, to an understanding of causes in the mechanics of this world below.  While Descartes argued that a monotheistic god clearly created the world, as reason tells us all things have causes, he was condemned like Hobbes, Newton and others for arguing that nature works like a machine, and once caused proceeds largely on its own.  Descartes argued that the natural world, including animals and human bodies, are mechanical and unconscious, like a mechanical clock and unlike a human mind, and that the human mind and body are exclusively separate, a position known as Cartesian dualism.  The worst consequence of this was that Descartes practiced vivisection, cutting animals apart while still alive to learn about anatomy, and argued that animals do not have minds, feel nothing, and merely appear to behave as if in pain.  In one place, he even argued that the mistaken belief that animals can have conscious sensations is one of the worst obstacles to the progress of science and rationality.

In Descartes’ Meditations, he lays out the famous deceiving demon, remarkably similar to Avicenna’s Floating Man thought experiment.  In the beginning of the work, Descartes says he won’t tell us about his first meditations, “for they are so abstract and unusual that they will probably not be to the taste of everyone”, a thought he might have kept to himself.  Descartes argues that we all accept things that we believe to be certain, but sometimes these then turn out to be wrong.  Therefore, we cannot use certainty as the sole criterion for truth.  We have to separate out the categorically certain from the seemingly certain.  Descartes says that it seems certain that he is sitting by the fire writing, but we can doubt this and believe that he is simply dreaming that he is Descartes by the fire.

He then uses the example of madmen who think that they are kings or that their bodies are made out of glass.  Obviously, Descartes had some familiarity with madness and delusions, as did Avicenna.  King Charles the Sixth (VI), also known as Charles the Mad, ruled France until 1422.  He would sometimes forget his own name and run through his castle believing himself to be a wolf.  Also, he was afraid of being touched by others, fearing that he was made of glass.  When Descartes says that his audience is familiar with instances of insanity such as people believing they are made of glass, he is referring to Charles VI without mentioning him by name.

Let us remember Avicenna’s floating man thought experiment, in which he suggests that the reader imagine floating in a void and having all sensation, including of the body or senses, slowly taken away.  What are you left with as the essential factor once the accidental sensual factors are removed?  Our consciousness, awareness itself, stands alone as that which is evident in itself.  Descartes proposes a very similar thought experiment, realizing that the self-evidence of awareness can undercut Pyrrhonian skepticism.  He asks the reader to imagine that there is a deceiving demon that is trapping us in an illusion of a world, casting doubt on everything.  What is the one thing that must be, even if Satan can deceive us such that two and three seem to equal five but in fact equal six?  Consciousness, which Descartes lumps together with thinking, must exist even if it is deceived about everything else, and thus Descartes’ his famous line:  “I think, therefore I am”.