dechamplain - the material soul

I’m doing this mini-internship in a college this semester and I have to teach a two-part lesson about Descartes and the method. Part 1 will be a bit shorter since I have to give them a test at the beginning of class. The test is about Descartes’ Discourse, which they had to read, so I’ll be sure they that have at list a bit of an idea of what I’m talking about.

 Here’s my lesson plan for now.

Part 1: Skepticism and the rejection of dogmatism

First there’s an intro on science vs dogma before modernity. Then probably a chat about Galileo or Bruno. Then the Enlightenment and humanism, which will lead to the importance of scientific inquiry. Then two activities will have the student criticize naive empiricism and naive rationalism, in favor of a rational and empirical method of inquiry.

Activity 1 - Should you trust your senses?

Objective: realize that our perceptions are influenced by previous knowledge, develop skeptical thinking.

I’m trying to find a fun illusion where there is some top-down perception effect to demonstrate that. I thought of showing that very cool video with the basketball players and a gorilla, but it’s copyrighted and very expensive. Maybe an ambiguous or degraded figure.

Activity 2 - Should you trust your our mind?

Objective: realize that even “pure thinking” can lead to improbable and absurd results if it is not guided by a rational methodology.

I’ve prepared an estimation quiz that the students have to answer, e.g. what’s the height of the Eifell tower, how many bones in the human body, how many dots in a drawing I’m showing, etc. Everybody suck at that kind of quiz.

I will then show them that with a method they could have gotten much closer to the actual results. I hope it will prove that with no method you can’t really gain reliable knowledge.

Descartes and the method (plus feedback on the exam)

We will then pull out our Descartes’ Discourse and see wheat he had to say about doubt, dogma and the scientific method.

At the same time, I’ll give the answers to the test so they get an idea of their score. By then, they have to be absolutely thrilled to hear about scientific inquiry and leave class wanting to know everything about it.

Centuries before Antonio Damasio’s Descartes’ Error*, there was Leibniz, who also criticized Descartes’ conception of the body-soul relation, that we could summarize as:

1. The soul is an immaterial and immortal entity that “controls” the body;
2. The brain is the receptacle for the soul, more like an receiver than a computer;
3. The body is a fancy mechanism that transmits perceptions to and follow the orders of the soul.
4. The interface between body and soul is the pineal gland.

Except for point number 4, this conception corresponds to a popular folk-psychology view: the soul is a disembodied self, the body is a soulless vehicle. (While we’re on the topic: Mario and Denyse. Enough said.)

Leibniz himself had a pretty strange theory of the body-soul: there is no link between the corporal and spiritual self. They are in harmony like musicians in an orchestra — of course, God is the chef d’orchestre. But we are not God’s marionettes: Leibniz also has a (strange ad hoc) way of salvaging free will. In a few words, we choose what we are supposed to choose considering the context and information that we have (both of which are pre-programmed). That’s not really free free will, at least not arbitrary free will. But anyway, that leads us the Leibniz’s (Leibniz’?) answers to Descartes**.

Against point #1: Then why can’t I fine-tune every movement? Suppose I want to throw a stone at exactly ten yards. Why can’t I? Some people (like athletes, surgeons and dancers) can actually pull up that kind of stunts, but only after countless hours of training… their body.

Against point #2: That’s a unfounded hypothesis. Cartesians can not account for the union of the body and soul.

Against point #3: Then why are there perceptions that are felt by the body but never reach the soul? Leibniz gives the example of a man that is sleeping and is poked with a needle. He might change position, make a few grunting noises, but he will not have the idea “I am being poked with a needle”.

We already know that the cartesian view of the mind is currently not doing so well in the scientific community, despite strange attempts to reintroduce it using quantum-physics-saves-the-day type of argumentation. But studying Leibniz makes you realize that Descartes was already being refuted in his own era, and start to wonder why his model got so popular in the first place.

Of course, the leibnizian view is not really better, but at least nobody still believes that.

*If you haven’t read Damasio’s excellent book, there’s a summary written by Dan Dennet.

** Everything here comes from the letter to Arnauld of october 1687.