The main development or change in how Descartes understands the mind from Meditations on First Philosophy to Passions of the Soul is that in this latter book his theory makes it possible for the body to act without the mind. In fact, I argue, he doesn’t leave the mind any way to affect the body at all even though he of course wants it to. There are a couple of reasons for this state of affairs. First, as we saw in the first Cartesian Error, he argues that the only thing the mind can do is think, and the body cannot think at all. Then in the Second Error, he argues that emotions aren’t thinking and explains that the human body works in such a way as to be able to start, continue and end emotions and emotion-based behavior. I call this organization, this explanation, an example of half-duplex communication between body and mind, a type of communication I previously said was exemplified by walkie-talkies and text messages. Let’s briefly review why this can’t be a reasonable way to look at how the mind and body interact.
If the mind were like a walkie-talkie, by definition only one end at a time can communicate. So if you had a spider on your leg, what would have to happen for you to get rid of it? First, the body would feel the pressure on your flesh. But for your mind to know the spider was there too would require one of four things, all of which have problems and raise more questions than they answer, (at least for Descartes):
1) That by a stroke of luck, at the same moment when the body felt the pressure, the mind happened to not be communicating out any messages and so is able to receive transmission, OR
2) The body not only feels the pressure on the skin, but also “knows” that the mind should stop transmitting and instead listen, and can force the mind to do so by accompanying important messages with a message such as “over” to tell the brain to start talking, OR
3) The body itself would just “know” how to stop the bug (like a reflex), OR
4) The body is constantly transmitting messages whether or not the mind is in a position to hear them, and sometimes it listens in for whatever reason.
On the other hand, Plato, Aristotle and Lucretius argued for something different, an, interactive and reciprocal communication between the body and the mind (and the emotions), a process I called duplex communication. For them, the mind and the body are both duplex transmitters, such as cellular phones, which allow two constantly running communications to both be understood by their targets.
This not only fits common sense and firsthand experience, but our more advanced understanding of the body tells us this is correct. Duplex communication between the brain and the rest of the nervous system throughout the body allow for immediate response to outside stimuli by real-time measurement and analysis – Plato, Aristotle and Lucretius each saw that the body feels things that don’t quite rouse the mind, and that our bodies are actually sentient – aware – in a way akin to the way the mind is. The duplex process also allows for conscious analysis of the stimuli, the body’s responses, the results of the responses, what goals are being achieved, and what goals might be better, as well as the ability to seek after those goals. The body can run “on its own” but a conscious person can study her reactions and change her behavior to her preference. After all, they are made of the same stuff. Half duplex communication doesn’t allow this.
So the third Cartesian Error is that the theory cannot explain how the mind and body could have duplex communication, which the P-A-L theory gave an excellent argument for, and which I conclude is a fundamental aspect of the emotions backed up by contemporary research. More specifically, third error has to do with how Descartes thinks the mind and body communicate with each other.
Descartes’ half-duplex theory argues that the mind/soul is united to all parts of the body, not just the pineal gland (If you read carefully this theory is also there in Meditation VI) but that the soul is able to exercise its unique function – thinking – best in the pineal gland (and its my opinion that he really does think of it as more physically extended than he is usually given credit for). He says that the soul and body act on each other by taking turns “radiating”: as in the soul “radiates” into the rest of the body from the pineal gland. Think of it as sort of like an x-ray in reverse. Instead of shooting x-rays through our body to give us an image of our body, things like bears shoot ‘bear-rays’ at our eyes. A similar process happens from the pineal gland to the soul and vice versa. This is completely incorrect but such particulars don’t really matter. What matters is that he has in mind a physical process by which he thinks we receive our sensory information, and it works like in the diagram above. Think of sending a text or SMS message to a friend with your cell phone. Basically, what happens is that a message goes from your phone to an SMS site, and the site attempts to deliver your message to the other phone. If it is ‘delivered’, your friend can read and reply in the same manner.
Here is a “play by play” of his argument:
1) the soul is truly joined to the whole body, no part is excluded,
2) because of the centrality of the [pineal] gland’s location the soul can perform its function in a more particular way there than anywhere else,
3) The central location of the pineal gland allows the soul to “better alter the course of the spirits (chemicals) with the slightest movement”.
4) Similarly, the slightest change in the course of the spirits can greatly change the movements of the pineal gland, affecting the soul greatly.
5) This activity can happen because of the “mediation” of the spirits and the nerves and blood that carry them.
6) Our bodies use “fire” or “heat” to make all possible movements, and it is wrong to think that the soul can impart either to our bodies (A5-A8).
So what we’ve learned here is that because
A) Descartes has a complete, purely physical account of how sense perception and muscular movement are possible,
B) we have all manner of non-conscious motion (eating, breathing, walking aimlessly, etc) and
C) He firmly argues the soul imparts no motion to the body,
then it is fundamentally impossible on his theory for duplex communication to occur between the mind and the body. In fact, it seems impossible for him to seriously, coherently defend any meaningful communication between them. At best what he has is a “half-duplex” system, but that doesn’t match reality and it couldn’t work, as we discussed briefly in the sections on Lucretius.
The next post, the last one to focus on Descartes, will discuss the ethical implications of the three Cartesian Errors.
As I explained in the previous post, Descartes is fundamentally concerned with defending the position that the exclusive function of the soul is thought and that everything else is the function of the body – exclusive meaning only the soul can think and the soul can do nothing but think.
I also told you that the Second Cartesian error is the irreparable separation of emotion from thinking, which forces Descartes to make up a way to sneak intelligence into emotions once he realizes he’s made it possible for emotions not to involve the soul. Over the next couple of posts, I’ll explain why it’s a very bad mistake, but I’ll begin by saying that I started this whole project with the plan to show that it is incorrect to separate emotions from cognition.
I say its incorrect because I think emotions and emotional behavior clearly demonstrate thinking or cognition. And in previous posts I fleshed out a theory, which I called P-A-L, that treats emotions as a type of cognition while also accounting for the fact that they are also physiological phenomena. I also explained how Stoicism rose to challenge that theory and put forth the competing idea that the emotions are purely mental phenomenon, purely thought and have nothing to do with the body. Descartes’s goal is to further this project by adding a highly sophisticated attempt at a scientific look at how the body works. You could even go so far as to say that when it was written, Descartes theory of the emotions was state of the art for science and medicine at the time. Because of that, and even though it is hopelessly wrong in the specifics of physiology, we need to get some familiarity with what he thought was going on.
Earlier, I explained why it was a mistake for Descartes to completely split mind and body the way he did, calling it the First Cartesian Error. But if you think about it, its really two separate errors in one decision. Consider that though Descartes decided that only the mind could think and could do nothing but think, he could have argued for a split that did more sharing of cognitive abilities. Unfortunately, the way he chose to do it splits emotion from cognition or thinking. Enough background, let’s start unpacking the Second Cartesian Error.
Descartes ties himself in knots trying to maintain his strict mind-body dualism while at the same time trying to explain the physiological aspects of emotions and emotionally charged actions. To get out of the knots he has to find some way to imbue emotion with intelligence, since they are supposed to be “of the soul”. Unfortunately, his solution is ad hoc.
What’s an Ad Hoc Hypothesis?
An Ad Hoc hypothesis, claim or distinction is the use of an unsubstantiated claim or hypothesis to defend your preferred theory or explanation from fact that contradict it. I’ll give two examples, one where its easy to see that an ad hoc hypothesis is being used, and that it is unfair, and another where it is unfair but is harder to see at first.
Imagine the following argument between Sue and Tom:
Tom: Sue, I’m going to use our last $20 bucks to play roulette because I know what the winning number will be.
Sue: I wish I could agree, but there’s no way to predict the roulette and the odds of winning are so low that it’s really a waste of money. Let’s just go get a drink and call it a night.
Tom: (Bets on roulette and loses)
Sue: See, I told you you can’t predict a winning roulette number.
Tom: I only failed because you didn’t have faith in my ability. Your negativity made me lose focus and obscured by vision.
Sue: (Rolls eyes and sighs).
As you probably already get, Tom’s argument has problems. First, there is no way to prove that lack of faith or “negativity” caused him to fail. Second, his argument doesn’t even really address the facts Sue’s criticism depend on– games of chance such as roulette are basically random, there’s no skill involved in guessing the outcome; and there’s no credible evidence for clairvoyance. Tom says nothing about how he might be able to pick numbers, so there’s no reason to believe him in the first place. But given that he does believe in his ‘ability’, when it doesn’t work out, he’s the one who needs to explain why. In this case, he simply makes up a reason why he wasn’t wrong about his ability. A reason that can’t be tested and that doesn’t even address the criticisms of his theory.
Imagine the following situation:
Sue asks Tom to pick up a 6-pack of their favorite beer from Seller Bob’s on the way home. Tom meant to but got caught up listening to his favorite podcast and arrived home forgetting to grab the beer. Sue asks why he didn’t go to Seller Bob’s and since he was afraid of making her mad, he lied and said he did go, but that they were out of the beer. That is, his explanation for not having beer is “I went but there was none”.
Sue was confused by this because she’d called Seller Bob to make sure they had the beer just before calling Tom with her request, and the manager assured her they had plenty. She explains this to Tom and Tom realizes that while his explanation is now in some doubt, it’s not clearly false. So he tells Sue that what probably happened was that a bunch of the local college kids probably swarmed the place and grabbed all of that beer before he arrived. So he’s changed his explanation to “I went, but I others beat me to it and when I arrived there was none.” Now, if Sue was sufficiently upset or skeptical of Tom, she might go to the store herself and see if there was any left, and ask about recent sales. Or she might just not care enough and move on.
So why is Tom guilty of ad hoc arguing? He wanted to get the beer but failed. He wanted to hide his mistake so he offered a hypothesis about why he didn’t have the beer. His story might have been true but Sue came up with a strong objection to it. One that didn’t disprove it, but that required more evidence for the theory. Tom takes Sue’s objection and makes it a part of his theory, he adjusted his original theory in the face of objections. This isn’t wrong on its own, but in this case, Tom knew the theory was probably not factually true, and that he only put it forth because wanted Sue to believe it. However, even if Sue accepts his new theory, it doesn’t take away the fact that he simply made up the explanation of the afternoon’s events.
Here’s a good website discussing ad hoc hypotheses if you’d like to read more. We’ll stop here for now and next time we’ll work to understand Descartes’ theory and what I argue is his ad hoc attempt to save it.