Friday, October 23, 2009

On Astrology, Ptolemy, and the Four Elements: The Use of Bad Theories

I was finally getting around to reading the last book of the Hitchhiker's Guide pentology, and I find a quote in there on a topic for which I had already written down some notes order to write a blog post:

"I know that astrology isn't a science," said Gail. "Of course it isn't. It's just an arbitrary set of rules like chess or tennis or - what's that strange thing you British play?" "Er, cricket? Self-loathing?" "Parliamentary democracy. The rules just kind of got there. They don't make any kind of sense except in terms of themselves. But when you start to exercise those rules, all sorts of processes start to happen and you start to find out all sorts of stuff about people. In astrology the rules happen to be about stars and planets, but they could be about ducks and drakes for all the difference it would make. It's just a way of thinking about a problem which lets the shape of that problem begin to emerge. The more rules, the tinier the rules, the more arbitrary they are, the better. It's like throwing a handful of fine graphite dust on a piece of paper to see where the hidden indentations are. It lets you see the words that were written on the piece of paper above it that's now been taken away and hidden. The graphite's not important. It's just the means of revealing their indentations."
So, what is the importance of theory, especially in philosophy?

It seems that I can look at theories that seem to be flawed, and still learn from them. I can read the Renaissance Platonist Ficino on astrology, and still make sense of what he is doing. His division of the world into spheres controlled by the different planets, each under the aspect of a god, a muse, and an aspect of Bacchus, can be insightful even when his reasons for the division have been thoroughly discredited. Similarly, personality theories can be helpful for understanding oneself. Myers-Briggs may lack rigorous scientific evidence, especially insofar as it posits specific explanations of how and why people act, and I may never fit completely into the INTP mold, but I still think that it is more useful for my own self-understanding than the scientifically developed Big Five test, which can group personality characteristics accurately but does not give anything underlying explanations.

Similarly, I can look at scientific achievements in the past which were grounded in bad theories. Astronomy was developed by and large within the Ptolemaic framework. And don't think that this was simply because everyone started with the theory: the data was explained rather well at first by the theory (we experience things rotating around the Earth, and most of the stars seem to stay in their places without big changes). People could continue to revise the theory to deal with the data, and even after people like Copernicus and Galileo, it took Newton and Kepler to establish why the Heliocentric model actually did explain the data better. A lot of astronomical data was accumulated in those Ptolemaic times. Would we have been able to understand as much as we did about the sky, without a wrong theory to organize our data and make it manageable?

Also, take medicine. Western medicine was by and large built on a four-element view of the world: things can be hot or cold, and they can be wet and dry, and different pairings give you the different elements. Makes sense, for a rough-and-ready view of the world. And you can read Galen or Avicenna or Maimonides using this theory in understanding medicine. They may not have been completely right, but they weren't completely wrong either; good doctors in any time or place generally leave their patients in better condition for the visit, or they get labeled as quacks. People notice if Doctor A's patients all die. So the empirical observations of these doctors were still a progress in knowledge, even though their theory was wrong: the four elements were not constituents of the world as building blocks for material mixtures. But this theory also let them be able to process complicated accounts of the human body; could there have been medicine without it?

One issue that has been coming up is that we seem able to advance in empirical knowledge in spite of, and even because of, wrong theories. But what about philosophical understanding? I hear it often said that, due to our increased knowledge of neurological processes, there is no place for dualism anymore. Hogwash. People have always known that if you get hit upside the head, your cognitive faculties will be impaired. We just know a bunch more ways to impair them, now. Avicenna had a rather dualistic account of the person, but again, he was a doctor. He knew about material interactions which interrelated with thought, and they were extensive. In general, medieval cognitional theory is pretty sophisticated and saves any sort of non-bodily cognition only for the highest and hardest cases involving pure intelligibles, which even then often still require some sort of material correlate. I fail to see how modern neuroscience changes the basic framework here, even if it can inspire utmost awe at the marvelous workings of our brains. It fills out the description, but leaves the general categories untouched.

So even within wrong theories, good philosophical categories may persist. And in addition, returning the the original quote, self- and humanistic-knowledge seems to arise clearly in some ways independently of theory. Is this part of the reason for Plato's fondness of myths?

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