Nick Bostrom’s introduction to the Doomsday Argument is an example of smart, cautious discussion of anthropic reasoning.
You should take the fact that the best argument that you can find for the proposition: “Rationality is optimal now, but it wasn’t in 1950.” is appealing to the Doomsday Argument, as evidence that your brain is in rationalization mode.
But … (and now I’m genuinely curious) why aren’t we living in a period way after rationality became the optimal choice? JulianMorrison and my suggestion provides the lower bound, but what is the upper bound?
To falsify the conjunction “Rationality is optimal now” and “Rationality was not optimal previously”, you only need to falsify one of the conjuncts. For example, “Rationality is not optimal now” or “Rationality was optimal previously”.
EDIT: I said that awkwardly. To change your mind regarding “Rationality is optimal now and rationality was not optimal previously”, you would have to change your mind regarding one of the conjuncts. For example, you could accept the statement “Rationality is not optimal now.”
So, anthropic reasoning involves using facts about how the observer came into being to “explain” certain supposed coincidences and thereby not give so much weight to alternative hypotheses which might need to be invoked to explain the coincidence.
In this case, there is a coincidence between us asserting that rationality is good for us, and us being the first generation out of a long line of humans for whom this is the case. (and, indeed, the same argument applies spatially as temporally; rationality is probably a bad move for many very disadvantaged people in the world today).
The alternative hypothesis under consideration is “rationality is not good for you, you are just rationalizing”.
So, I assume that I am sampled from the set of people who ask the question “is it optimal to be rational, or to delude myself?”. What is the probability of me answering “yes”? Well, JulianMorrison argues (correctly, IMO) that there is a systematic correlation between being able to ask the question and answering “yes”, so the probability is not worryingly small. Nothing unusual has happened here.
So we should not be suspicious that we are rationalizing just because we answered “yes”.
Secondly, what is the probability of me finding myself to be the first (or second) generation of humans for which the answer to this question is “yes”? In the case where there are zillions of similar humans in the future, this probability could be very small. But… there’s no interesting alternative hypothesis to explain this coincidence, so we can’t conclude anything particularly interesting.
Yeah, you’re basically making the doomsday argument. Note that you could use the same reasoning about any question that you expect to come up from time to time, for instance “do I like cheese?”
Nick Bostrom’s introduction to the Doomsday Argument is an example of smart, cautious discussion of anthropic reasoning.
You should take the fact that the best argument that you can find for the proposition: “Rationality is optimal now, but it wasn’t in 1950.” is appealing to the Doomsday Argument, as evidence that your brain is in rationalization mode.
But … (and now I’m genuinely curious) why aren’t we living in a period way after rationality became the optimal choice? JulianMorrison and my suggestion provides the lower bound, but what is the upper bound?
To falsify the conjunction “Rationality is optimal now” and “Rationality was not optimal previously”, you only need to falsify one of the conjuncts. For example, “Rationality is not optimal now” or “Rationality was optimal previously”.
EDIT: I said that awkwardly. To change your mind regarding “Rationality is optimal now and rationality was not optimal previously”, you would have to change your mind regarding one of the conjuncts. For example, you could accept the statement “Rationality is not optimal now.”
Robin Hanson has posted on the costs of rationality.
So, anthropic reasoning involves using facts about how the observer came into being to “explain” certain supposed coincidences and thereby not give so much weight to alternative hypotheses which might need to be invoked to explain the coincidence.
In this case, there is a coincidence between us asserting that rationality is good for us, and us being the first generation out of a long line of humans for whom this is the case. (and, indeed, the same argument applies spatially as temporally; rationality is probably a bad move for many very disadvantaged people in the world today).
The alternative hypothesis under consideration is “rationality is not good for you, you are just rationalizing”.
So, I assume that I am sampled from the set of people who ask the question “is it optimal to be rational, or to delude myself?”. What is the probability of me answering “yes”? Well, JulianMorrison argues (correctly, IMO) that there is a systematic correlation between being able to ask the question and answering “yes”, so the probability is not worryingly small. Nothing unusual has happened here.
So we should not be suspicious that we are rationalizing just because we answered “yes”.
Secondly, what is the probability of me finding myself to be the first (or second) generation of humans for which the answer to this question is “yes”? In the case where there are zillions of similar humans in the future, this probability could be very small. But… there’s no interesting alternative hypothesis to explain this coincidence, so we can’t conclude anything particularly interesting.
Yeah, you’re basically making the doomsday argument. Note that you could use the same reasoning about any question that you expect to come up from time to time, for instance “do I like cheese?”
Correct. I’ve edited my comment since you commented. Read the corrected version and critique…
Please reread my post. I think I was editing while you were reading my post.
Are you asking an explanation for why anthropic reasoning is bunk?