Sunday, October 05, 2008

Some lecture notes on Descartes

Since we will soon be starting Descartes today in Philosophy 101, I thought I would put some notes I wrote up about him on the blog. Comments and dialogue welcome of course.

Rene Descartes
I. The Impact of Modern Science
II. Three Goals
A. Find Certainty
B. Establish science on a firm foundation
C. Reconcile science and religion
III. Uncertainty about beliefs caused by intellectual, ecclesiastical, and political upheaval
A. Intellectual upheaval: Change from a geocentric view to a heliocentric view (the sun, not the earth is the center of everything)
B. Ecclesiastical upheaval: Instead of one Church in control of everything, Europe is divided between Catholics and Protestants
C. Political upheaval: Descartes time saw the rise of the modern state, and the colonization of the Americas. It also saw 30 years of war over religion, resulting in the slaughter of 1/3 of the population of Europe.
IV. Threat of materialism and determinism
A. Modern science moves in the direction of viewing the world as a machine
B. But if the world is a machine, and we are just one more part of the world, then we are machines
C. If we are machines, then whether we do right or do wrong is a function of how we were programmed. Given the basic laws of the universe and the initial positions of the atoms, we could not have done otherwise from what we did.
D. If we could not have done otherwise from what we did, then the idea of sin makes no sense. We are not, in any significant sense, responsible for our actions. What’s worse, if you assume there’s a God, the God is responsible for all of our worst sins. This does not seem compatible with the idea of a perfectly good God.
V. The Jesuit solution: The Protestants, for example, maintained that it was possible to doubt the truth of the Church’s teaching by appealing to the Bible. At the Jesuit school that Descartes attended, they taught him that this would result in an unending chain of doubts. You can doubt the Church on the basis of the Bible. You can doubt the Bible on the basis of science. You can doubt science on the ground that it appeals to sense experience, which can be doubted. Once the spiral of doubt starts, it can’t be stopped. So just believe what Mother Church tells you to, and don’t ask so many questions.
A. Descartes is not satisfied with the Jesuit Solution. However, he does learn something from the Jesuit method. But he develops the method of universal doubt not to undermine confidence and force reliance on the authority of the Church, but to discover what he can really be sure of.
VI. Two models of knowledge: The house model and the boat model. According to the house model, what makes a belief system stad up is its foundation. If a house is shaking, tear it down, put in a secure foundation, and build it up again. On the boat model (attributed to Neurath), we have to replace planks as necessary, but tearing the whole boat apart would be a mistake that would cause the boat to sink.
VII. Method of doubt: Doubt everything that can possibly be doubted, not simply what can reasonably be doubted.
A. Sense experience and the Dream Conjecture. Could I really be dreaming? Well what if I pinch myself. But then I could be dreaming the pinch. So I pinch myself again, and again, and again, until I really do go unconscious and start dreaming!
B. Mathematical Truths: Descartes introduces the Evil Demon conjecture. Is it possible that SATAN IS CONTROLLING YOUR MIND? (Perhaps you have been listening to too much rock music, with Satanic lyrics put in backwards, and now SATAN IS CONTROLLING YOUR MIND). Well, what Descartes means is an omnipotent being (unlike the fallen angel Lucifer) who is dedicated to deceiving everyone as much as possible. In order to discover what we can really be sure of , Descartes introduces the Satan Test. Something can be included in the foundations of knowledge only if, even on the assumption that Satan is controlling your mind, and wants to deceive you as much as possible, you can be sure that this belief is true.
C. Can anything pass the Satan test? Surely not the knowledge that Bush is President. That could be a media hoax. Or your belief that you are now sitting in a chair? A piece of cake for the devil. How about math? Descartes says that perhaps 2 + 2 = 5, but Satan has deceived you into thinking that 2 + 2 = 4. (I have my doubts about his position on this one, but let’s give the man the benefit of the doubt.)
D. How about the belief that I am now thinking. Could Satan deceive me into thinking that I am now thinking? Well, if he DECEIVED me into thinking that I am now thinking, then I would have to not be thinking. On the other hand, if I had the deceptive thought that I am now thinking, I would have to be thinking. The idea that I am now thinking is indubitable, because a contradiction emerges when I attempt to consider that possibility of being deceived about it.
E. What about the belief that I exist. Well, if I can be sure that I am thinking, then it follows that I exist. Or, as you no doubt heard before you ever took Philosophy, “I think therefore I am.” Although you may have heard it a million times (in fact it’s a great thing to say after a few beers if you want to impress someone with how deep a thinker you are-NOT), this is what it means in its original context. “I think” and “I exist” pass the Satan test, because even on the assumption that Satan is controlling my mind, he can’t possibly deceive me about these two claims.


Anonymous said...

"I exist" is something of a slippery assertion.

What do we mean by "I"?

Is the 56 year-old "I" the same as the six-year old "I" of half a century ago? What stays constant? Is the "I" a process rather than a thing?

Also, "to exist" is an arbitrary concept. Science shows us that nothing exists unchanged for even a millisecond. If we say that something 'exists', all we are stating is that an aggregation of components hangs together and remains relatively unchanged long enough for our practical purposes.

The atmosphere exists, a lightning flash happens. A thunderstorm both happens and sort of exists for a while.

My car is a process for converting metal into rust and fossil fuels into greenhouse gases. It exists for a while and then fades as it reaches the end of its bathtub curve. The point at which it ceases to exist as a car is fairly arbitrary and depends on how much I wish to spend to keep it going.

Viewed on a long enough timescale, galaxies, stars and planets are processes or events.

The impermanence of all composite phenomena is a deep ontological truth. The 'existence' of any composite phenomenon is a useful but essentially shallow arbitrary designation.

Maybe Descartes should have said "Impermanence is experienced" - nobody could delude him about that.

Anonymous said...

First point in reply to 42 is that he assumes that we cannot know the proposition "I exist" is true unless we know many things about the nature of "I". I find this assumption unwarranted as does Descartes.

Secondly, if it were true that "Science shows us that nothing exists unchanged for even a milisecond." this would not show that existence was an arbitray concept. Although the expression "existence" we use for this concept may be said to be arbitrary. Further it is a myth (normally held by those adhering to some Eastern mysticism that science shows that nothing exists unchanged for even a millisecond).

Finally 42 asserts that the imperenance of all composite phenomena is a deep ontological truth as if this were a criticism of Descartes whereas Descartes recognised and accepted a sense in which the physical world was always changing (and one wherein it was not) but this did not alter the nature of the self. Hence 42's arguments are not directed against Descartes arguments and suggests that 42 has not read his Descartes.

exapologist said...

From a didactic point of view, great notes! I'm still getting my act together when it comes to setting the historical context for my students. I found your notes helpful in this regard!

All the best,


Charlie said...

Old point, but here goes...

Consider the following principle:

Any belief with respect to which I do not enjoy certitude should be relinquished.

Something like that is going to play a crucial role in any of Descartes' skeptical arguments. This principle, along with beliefs like possibly, Satan is controlling my mind, seems much less certain than beliefs like 2+2=4 and there are material objects.