Monday, January 03, 2011

What is Explanation?

I've started reading this book called 'Guns, Germs and Steel' by Jared Diamond. The beginning was a bit irritating because the author spends the entire preface stating that it is NOT a racist and/or eurocentric book. Sounded a bit like the old 'I'm not racist, many of my friends are black' argument to me. But I'm giving him a chance. Will reserve my final opinion until I'm done with the book.

The authors central thesis is this -- different societies developed differently over the course of history. He wants to know why. And he repeatedly claims that he is looking for the 'ultimate explanation' of these differences. This puzzles me slightly.

What could one mean by the 'ultimate explanation' in the context of historical differences between societies? History is an endless chain of cause and effect. A web would be a better word to describe it. There are multiple causes and multiple effects for each historical incident. Many of these are well studied. We keep finding new ones, which is good because our knowledge advances that way. We also keep questioning and perhaps throwing out the old ones which is also good because skepticism is the fundamental characteristic of the scientific attitude. In short, it's business as usual for historians.

But the author is not talking about these chains or webs of historical causes and effects. He is looking for an explanation that goes beyond this. I do not know what exactly he might mean by this.

History goes not lend itself to 'explaining' in the same way that physical phenomenon do. Physical explanations are concerned with precise mathematical relationships between phenomenon. Newton could observe apples falling and come up with the laws of gravitation. That is, he could write down a precise mathematical relationship between the masses of the objects and the gravitational pull between them. He could also write down the relationship between the amount of pull and the speed that an object attained under that force.

But that is not all, physical explanations are also reductionist. That is, you can isolate effects or 'variables' as fancy scientists like to call them. An applet falling under the bright blue sky is being attracted not only by the earth, but also by the moon, the sun and the entire galaxy. The beauty of gravitation is, you can isolate the effect of the earth, the sun, the moon and the galaxy and measure them independently. Then you can add all of those effects up and you will get the total effect. The whole IS the sum of the parts. This is called the principle of superposition. It is important to know where it applies and where it doesn't. Physics books explicitly state where it applies.

It is lucky for us engineers that so many physical phenomenon follow the principle of superposition. This allows us to isolate effects, study and quantify them and then put them together in the end to do all those magical things we do.

However, it is hazardous to bring this same reductionist thinking to other spheres. Food and nutrition is one. Michael Pollan points out in 'The Omnivore's Dilemma' that food doesn't quite follow the principle of superposition. Drinking wine and eating carrots together does NOT produce the same effect as drinking wine and eating carrots separately.

The same applies to history. The whole is so much more greater than the sum of it's parts that it makes little sense to isolate effects. Did human beings develop number systems because they needed to keep accounts or could they keep accounts because they had number systems? What role did the hard wiring of the brain play in this? What role did the underlying philosophy of the culture play? For example, the Indians may have invented the zero because they were so very concerned (philosophically) with nothingness or shunyata. All these various factors are so strongly interconnected that it makes little sense to isolate the effect of one particular variable.

But that's precisely what Jared Diamond seems to be aiming at. And while I'm not opposed to such analysis as an intellectual exercise, touting it as some 'ultimate explanation' seems to be a bit too much to me.

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