Our actions have lots of unpredictable effects. If you drive to the store, you will delay everyone behind you in traffic. This will change when they next have sex, thus completely changing the identity of their future child. A different sperm and egg will fuse. This new child will go on to take a staggeringly large number of actions, each of which will change the identity of still more people. For this reason, because of your decision to drive to the store, the world hundreds of years down the line will be completely different.
I agree small actions like driving to the store may have large actual consequences. However, I believe their expected consequences are very small. I think the probability of any given child being born will be practically the same regardless of whether one drives to the store or not. One could tell a story where driving to the store leads to A being born instead of B. However, one could tell a story practically as convincing where driving to the store leads to B being born instead of A. So one should practically stick to the prior that driving to the store does change the probability of A or B being born. Likewise, driving to the store could cause a given hurricane H, but is almost as likely to prevent it. So the probability of hurricane H is practically the same regardless of whether one drives to the store or not.
@Derek Shiller, I would be curious to know your thoughts on the above.
From your perspective now, given your uncertainty, you might have no reason to think that the drive changes things in a better or worse way, and so the expected value derived from taking the expected value of each possible consequence considered piecemeal and summed up might be neutral.
I think if you accept some degree of objective chance, this might completely resolve the problem. (I explore this idea, without direct connection to incomparability, here: https://philpapers.org/rec/SHICAT-11)
It is consistent with a purely subjective neutral expected value, however, that you might be quite sure that the results, if revealed in their full detail, would be incomparable.
This creates an intuitive tension. There is something called the “Principle of Reflection”—it is a bit controversial, but very intuitive—that says roughly that if you know you would believe something if you were put into a better epistemic position, you should believe it now. The challenge Bulldog raises relies on taking reflection seriously and thinking that we would almost surely see incomparability if we looked closely at all the details, so we should accept incomparability now.
Thanks for sharing your thoughts, Derek. I did not know about your paper.
One would ideally recognise the existing uncertainty, and become less uncertain with further research. However, I think it is very easy to underestimate uncertainty. So I can easily see further research making one more uncertain. Yet, this would only lead to incomparability if one is open to impresice probabilities (I am not)?
Hi Matthew.
I agree small actions like driving to the store may have large actual consequences. However, I believe their expected consequences are very small. I think the probability of any given child being born will be practically the same regardless of whether one drives to the store or not. One could tell a story where driving to the store leads to A being born instead of B. However, one could tell a story practically as convincing where driving to the store leads to B being born instead of A. So one should practically stick to the prior that driving to the store does change the probability of A or B being born. Likewise, driving to the store could cause a given hurricane H, but is almost as likely to prevent it. So the probability of hurricane H is practically the same regardless of whether one drives to the store or not.
@Derek Shiller, I would be curious to know your thoughts on the above.
From your perspective now, given your uncertainty, you might have no reason to think that the drive changes things in a better or worse way, and so the expected value derived from taking the expected value of each possible consequence considered piecemeal and summed up might be neutral.
I think if you accept some degree of objective chance, this might completely resolve the problem. (I explore this idea, without direct connection to incomparability, here: https://philpapers.org/rec/SHICAT-11)
It is consistent with a purely subjective neutral expected value, however, that you might be quite sure that the results, if revealed in their full detail, would be incomparable.
This creates an intuitive tension. There is something called the “Principle of Reflection”—it is a bit controversial, but very intuitive—that says roughly that if you know you would believe something if you were put into a better epistemic position, you should believe it now. The challenge Bulldog raises relies on taking reflection seriously and thinking that we would almost surely see incomparability if we looked closely at all the details, so we should accept incomparability now.
Thanks for sharing your thoughts, Derek. I did not know about your paper.
One would ideally recognise the existing uncertainty, and become less uncertain with further research. However, I think it is very easy to underestimate uncertainty. So I can easily see further research making one more uncertain. Yet, this would only lead to incomparability if one is open to impresice probabilities (I am not)?