The surprise is that an incredibly highly selection-optimized trait isn’t selection-optimized to work at all in a surprising fraction of people (including myself). So many bits of optimization pressure exerted, only to choke on the last few.
Well then it’s not all that highly selection-optimized. The reality is that many people do have poor eyesight and they do survive and reproduce. Why do you expect stronger selection than is in fact the case?
Look, for thousands of generations, natural selection applied its limited quantity of optimization pressure toward refining the eye. But now it’s at a point where natural selection only needs a few more bits of optimization to effect a huge vision improvement by turning a great-but-broken eye into a great eye.
The fact that most people have fantastic vision shows that this trait is high utility for natural selection to optimize. So it’s astounding that natural selection doesn’t think it’s worth selecting for working fantastic eyes over broken fantastic eyes, when that selection only takes a few bits to make. Natural selection has already proved its willingness to spend way more bits on way less profound vision imrovements, get it?
As Eliezer pointed out, the modern prevalence of bad vision is probably due to developmental factors specific to the modern world.
Just because you can imagine a better eye, doesn’t mean that evolution will select for it. Evolution only selects for things that help the organisms it’s acting on produce children and grandchildren, and it seems at least plausible to me that perfect eyesight isn’t in that category, in humans. Even before we invented glasses, living in groups would have allowed us to assign the individuals with the best eyesight to do the tasks that required it, leaving those with a tendency toward nearsightedness to do less demanding tasks and still contribute to the tribe and win mates. In fact, in such a scenario it may even be plausible for nearsightedness to be selected for: It seems to me that someone assigned to fishing or planting would be less likely to be eaten by a tiger than someone assigned to hunting.
First of all I’m not “imagining a better eye”; by “fantastic eye” I mean the eye that natural selection spent 10,000 bits of optimization to create. Natural selection spent 10,000 bits for 10 units of eye goodness, then left 1⁄3 of us with a 5 bit optimization shortage that reduces our eye goodness by 3 units.
So I’m saying, if natural selection thought a unit of eye goodness is worth 1,000 bits, up to 10 units, why in modern humans doesn’t it purchase 3 whole units for only 5 bits—the same 3 units it previously purchased for 3333 bits?
I am aware of your general point that natural selection doesn’t always evolve things toward cool engineering accomplishments, but your just-so story about potential advantages of nearsightedness doesn’t reduce my surprise.
Your strength as a rationalist is to be more confused by fiction than by reality. Making up a story to explain the facts in retrospect is not a reliable algorithm for guessing the causal structure of eye-goodness and its consequences. So don’t increase the posterior probability of observing the data as if your story is evidence for it—stay confused.
So I’m saying, if natural selection thought a unit of eye goodness is worth 1,000 bits, up to 10 units, why in modern humans doesn’t it purchase 3 whole units for only 5 bits—the same 3 units it previously purchased for 3333 bits?
Perhaps, in the current environment, those 3 units aren’t worth 5 bits, even though at one point they were worth 3,333 bits. (Evolution thoroughly ignores the sunk cost fallacy.)
This suggestion doesn’t preclude other hypotheses; in fact, I’m not even intending to suggest that it’s a particularly likely scenario—hence my use of the word plausible rather than anything more enthusiastic. But it is a plausible one, which you appeared to be vigorously denying was even possible earlier. Disregarding hypotheses for no good reason isn’t particularly good rationality, either.
The surprise is that an incredibly highly selection-optimized trait isn’t selection-optimized to work at all in a surprising fraction of people (including myself). So many bits of optimization pressure exerted, only to choke on the last few.
Well then it’s not all that highly selection-optimized. The reality is that many people do have poor eyesight and they do survive and reproduce. Why do you expect stronger selection than is in fact the case?
Look, for thousands of generations, natural selection applied its limited quantity of optimization pressure toward refining the eye. But now it’s at a point where natural selection only needs a few more bits of optimization to effect a huge vision improvement by turning a great-but-broken eye into a great eye.
The fact that most people have fantastic vision shows that this trait is high utility for natural selection to optimize. So it’s astounding that natural selection doesn’t think it’s worth selecting for working fantastic eyes over broken fantastic eyes, when that selection only takes a few bits to make. Natural selection has already proved its willingness to spend way more bits on way less profound vision imrovements, get it?
As Eliezer pointed out, the modern prevalence of bad vision is probably due to developmental factors specific to the modern world.
Just because you can imagine a better eye, doesn’t mean that evolution will select for it. Evolution only selects for things that help the organisms it’s acting on produce children and grandchildren, and it seems at least plausible to me that perfect eyesight isn’t in that category, in humans. Even before we invented glasses, living in groups would have allowed us to assign the individuals with the best eyesight to do the tasks that required it, leaving those with a tendency toward nearsightedness to do less demanding tasks and still contribute to the tribe and win mates. In fact, in such a scenario it may even be plausible for nearsightedness to be selected for: It seems to me that someone assigned to fishing or planting would be less likely to be eaten by a tiger than someone assigned to hunting.
First of all I’m not “imagining a better eye”; by “fantastic eye” I mean the eye that natural selection spent 10,000 bits of optimization to create. Natural selection spent 10,000 bits for 10 units of eye goodness, then left 1⁄3 of us with a 5 bit optimization shortage that reduces our eye goodness by 3 units.
So I’m saying, if natural selection thought a unit of eye goodness is worth 1,000 bits, up to 10 units, why in modern humans doesn’t it purchase 3 whole units for only 5 bits—the same 3 units it previously purchased for 3333 bits?
I am aware of your general point that natural selection doesn’t always evolve things toward cool engineering accomplishments, but your just-so story about potential advantages of nearsightedness doesn’t reduce my surprise.
Your strength as a rationalist is to be more confused by fiction than by reality. Making up a story to explain the facts in retrospect is not a reliable algorithm for guessing the causal structure of eye-goodness and its consequences. So don’t increase the posterior probability of observing the data as if your story is evidence for it—stay confused.
Perhaps, in the current environment, those 3 units aren’t worth 5 bits, even though at one point they were worth 3,333 bits. (Evolution thoroughly ignores the sunk cost fallacy.)
This suggestion doesn’t preclude other hypotheses; in fact, I’m not even intending to suggest that it’s a particularly likely scenario—hence my use of the word plausible rather than anything more enthusiastic. But it is a plausible one, which you appeared to be vigorously denying was even possible earlier. Disregarding hypotheses for no good reason isn’t particularly good rationality, either.