The sensitivity to noise of the world

I’m reading Robert Broome’s book on climate change: Climate Matters. In it he makes two very hard to test claims viz:

  1. If governments were to behave very differently, it is likely this would change who future people are. The parents of those who would exist sans these drastic policy changes won’t meet up. Even if they do meet up, they won’t conceive their children at the exact same time. Hence we can’t treat the question of who exists as independent of government policy- even if the number of people who exist is independent of it.
  2. However if an individual changes their behaviour, this is unlikely to change who gets born in the future, or at least it will take several generations to ripple out.

The reason this question is interesting is related to Parfit’s Non-Identity Problem.

Now I agree with the first claim, but I disagree with the second claim. It seems to me that, for example, were I not to make this post on this blog, even though the effects of the post will be seemingly fairly negligible, the ripple out effects of me making this post means that the babies born say, two years from now will be completely different. The conditions around things like “which babies get born”- i.e. does the exact same sperm meet the exact same egg- are so fragile that you probably change them globally every time you go for a walk.

However, I have no way to prove this. The closest I can think of would be simulation studies, but even these wouldn’t be fully satisfactory. So I guess it just comes down to intuition. Do you think that the future is extremely sensitive to noise in this way or don’t you?

Very curious to hear what the blog thinks.

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2 thoughts on “The sensitivity to noise of the world

  1. Yes, the future is extremely sensitive to noise but still is very predictable, assuming we correctly choose the right prediction space. Like, if Jane and Mark are planning a date night, there is a 10% chance that conception will occur that night. But there is still only a 1e-9 chance that the child produced from it will be exactly like the one that arises. However, there is a 99.99% chance that the child will have black hair. It’s probably difficult for our brains to reconcile the idea that everything affects everything, yet many things are still inevitable.


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