SSA Doomsday: You are the hundred billionth human who ever lived (or something like that). If there are two hundred billion humans total, this is not very unusual. But if there are to be a quadrillion humans, you would be in a very unlikely situation, in the first 0.0...% or something.
Analogous argument: you’re told that you’re the smartest person in your extended family. This makes it more likely your extended family is small, rather than large. Replace “smartest” with any property that distinguishes you from the rest of humanity, and the argument follows.
Isn’t it more analogous to having a child be told “you’re 5 years old!” and for this reason this makes the kid believe they’re only likely to survive to around age 10?
Imagine you’re told you’re 50 years old… is only surviving to age 100 that bad a guess for a statistical argument which takes into account close to no information whatsoever?
(Reminds me of the reaction to the sunrise example for Laplace’s law.)
Let’s imagine that I’m an immortal being who has lived since prehistorical times—except that I lose all memories every 50 years or so, and my body and my mind reverts to the form of an infant, so that for all intends and purposes I’m a new person.
From prehistorical times, I can therefore think the Doomsday argument to myself—if I had the knowledge to do so. So when I’m Urgh the caveman, among the first 10,000 people I think that mankind is only likely to survive to around double that size, and when I’m Marconius the Roman, I think it likely that mankind is only likely to survive to around double that present size, and when I’m Aris Katsaris the modern Westerner, I think it likely that mankind is only likely to survive to around double this present size...
And each time, I effectively die and forget all my thoughts about Doomsday, and get born anew and reconstruct the Doomsday argument for myself. And can do so for as long as humanity lasts, and it never actually provides me any new information about how long humanity will last.
Until the point where I’m made physically or mentally immortal I guess, and no longer die, at which point I no longer ask the Doomsday argument again, because I first asked it millenia back and remember it.
I don’t know. This chain of thought above makes me intuitively think the Doomsday argument is bollocks, but I don’t know if it will have the same effect on anyone else.
Why does one example matter? The Doomsday argument is over billions of people (something like >100b so far), so one immortal—who doesn’t even exist—shows nothing. He’s wrong a few hundred times, so what—your immortal adds nothing at all to just pointing out that Romans or cavemen would’ve been wrong.
Shouldn’t it be either over all lifeforms or only over people who’ve heard and are able to appreciate the Doomsday argument?
so one immortal—who doesn’t even exist—shows nothing
The example of the immortal is just a trick helpful of thinking about individual lives as not especially meaningful to probabilities in an external sense. Your brain loses cognition and memory, its atoms eventually become part of many other people—in a sense, we’re all this “immortal”—is it meaningful in a mathematical sense to label one particular “life” and say “I was born early” or “I was born late”?
I don’t know. I admit myself just confused over all this.
But if there are to be a quadrillion humans, you would be in a very unlikely situation, in the first 0.0...% or something.
Again the finiteness assumption, which presumes the Doomsday (barring infinite lifespan, which is just another infinity) to begin with. This is a trivial tautology. I’m growing more and more disenchanted with this area of research :(
SSA Doomsday: You are the hundred billionth human who ever lived (or something like that). If there are two hundred billion humans total, this is not very unusual. But if there are to be a quadrillion humans, you would be in a very unlikely situation, in the first 0.0...% or something.
Analogous argument: you’re told that you’re the smartest person in your extended family. This makes it more likely your extended family is small, rather than large. Replace “smartest” with any property that distinguishes you from the rest of humanity, and the argument follows.
Isn’t it more analogous to having a child be told “you’re 5 years old!” and for this reason this makes the kid believe they’re only likely to survive to around age 10?
That seems like a reasonable conclusion for the child to draw, in the absence of other evidence (like, say, the ages of the people around them).
Actually, I think the right conclusion is that they’re likely to live to about 5*e years, not 10, but the idea is similar.
Imagine you’re told you’re 50 years old… is only surviving to age 100 that bad a guess for a statistical argument which takes into account close to no information whatsoever?
(Reminds me of the reaction to the sunrise example for Laplace’s law.)
Let’s imagine that I’m an immortal being who has lived since prehistorical times—except that I lose all memories every 50 years or so, and my body and my mind reverts to the form of an infant, so that for all intends and purposes I’m a new person.
From prehistorical times, I can therefore think the Doomsday argument to myself—if I had the knowledge to do so. So when I’m Urgh the caveman, among the first 10,000 people I think that mankind is only likely to survive to around double that size, and when I’m Marconius the Roman, I think it likely that mankind is only likely to survive to around double that present size, and when I’m Aris Katsaris the modern Westerner, I think it likely that mankind is only likely to survive to around double this present size...
And each time, I effectively die and forget all my thoughts about Doomsday, and get born anew and reconstruct the Doomsday argument for myself. And can do so for as long as humanity lasts, and it never actually provides me any new information about how long humanity will last.
Until the point where I’m made physically or mentally immortal I guess, and no longer die, at which point I no longer ask the Doomsday argument again, because I first asked it millenia back and remember it.
I don’t know. This chain of thought above makes me intuitively think the Doomsday argument is bollocks, but I don’t know if it will have the same effect on anyone else.
In an argument made confusing by manipulating the sample, I don’t think it’s very helpful to make an even weirder sample.
Why does one example matter? The Doomsday argument is over billions of people (something like >100b so far), so one immortal—who doesn’t even exist—shows nothing. He’s wrong a few hundred times, so what—your immortal adds nothing at all to just pointing out that Romans or cavemen would’ve been wrong.
Shouldn’t it be either over all lifeforms or only over people who’ve heard and are able to appreciate the Doomsday argument?
The example of the immortal is just a trick helpful of thinking about individual lives as not especially meaningful to probabilities in an external sense. Your brain loses cognition and memory, its atoms eventually become part of many other people—in a sense, we’re all this “immortal”—is it meaningful in a mathematical sense to label one particular “life” and say “I was born early” or “I was born late”?
I don’t know. I admit myself just confused over all this.
Again the finiteness assumption, which presumes the Doomsday (barring infinite lifespan, which is just another infinity) to begin with. This is a trivial tautology. I’m growing more and more disenchanted with this area of research :(
Which is one of the reason I recommend sidstepping the whole argument, and using “Anthropic decision theory” http://lesswrong.com/lw/891/anthropic_decision_theory_i_sleeping_beauty_and/