Tuesday, December 29, 2009

An idea that changed the world. Can you name one?

At some point in a very interesting NOVA PBS show, a scholar says something we hear quite often: monotheism was a revolutionary idea that completely changed the world.

Did it really change the world, though? If so, how much?

Technically, we have no way of knowing. I may be wrong, of course, but it seems to me that we often misjudge the impact of ideas and historical events because we have an intuitive notion of causality that's just wrong. If we have some event A that happened at time T, we think of its causal impact on the history of the world as the difference between what the world looked like before and after time T. But that's incorrect. The world after any event is different than it was before it, so by this metric, everything would be "revolutionary" and "world-changing."

The true causal impact of A is the difference between the state of our world after time T and the state of a hypothetical world in which A did not happen at T (also after time T). In other words, we tend to forget that causal inference is necessarily about counterfactuals.

So the impact of monotheism is the difference between our world after monotheism appeared, and a counterfactual world in which it did not appear. I have no idea how to even begin to estimate this difference, but in my completely subjective opinion it is quite small.

2 comments:

  1. hmm, maybe communism (and capitalism) because we got to see a few communist-style countries spring up in a fundamentally capitalist world..

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  2. Yeah... And sometimes history does us one better and comes up with a "natural experiment." For example, the splitting of Korea allowed us to directly observe the effects of different political institutions because South and North Korea are the same people so both genetics and culture are "controlled for."

    North Koreans would be much better off without history experimenting on them though.

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