There are numerous different arguments in this, without delving too deeply into them (One reason is I don't think I'm smart enough) all I can say is that no-one can foretell with 100% accuracy what is going to happen. Therefore anyone can provide an argument that delves into fantasy. Also I do not believe it is possible to time travel into the future, cos it doesn't exist yet. It hasn't been written into the scripts of time. It is possible to go backwards cos that has already happened. Anywho, happy theorising, I'm sure one of us will get it right but will never live to know it.
I wonder where Arto went. He hasn't come back since he started this thread methinks, and yet it's such a damn good one. Again, it's more-or-less a matter of philosophy with time travel. Does the future exist or is it merely a white photograph yet to coelesce into visible objects? Did the past exist or is it just a memory and gone forever? Again, either side of the argument makes a viable case.
This appears to be a variation on the old 'gambler's fallacy.' With white and black marbles, your probability of drawing the white marble is related to the number of black marbles that have been drawn previously - this allows you to make statistical arguments about how many marbles are in the box based on how many black marbles were drawn before the white one appeared. The probability of a doomsday event is not related to the number of people who have been born previously, so you can't use population counts to make a statistical argument about when doomsday will occur.
Well the thread is over a year old, so why stop now?! Carter Redux: Given your "birth rank" n, pick two other numbers nBIG and nSMALL to represent possible future populations. What is the chance that you being n means you are in nBIG vs. nSMALL? Chances are always be larger for nSMALL. n=60 billion is used in their examples, with nBIG being 100 trillion and nSMALL being 200 billion. Your chance of being 60 in 200 billion is larger than being 60 in 100 trillion. The problem: The argument can be shown for the absurdity it is; set nSMALL to be n+1 and nBIG to be n^1000. The argument always suggests that you should be the last person on earth, and that is true for all values of n. it for n=60 billion, or n=10, the results are the same. This is because you know what n is. Pick 15 for n and they say "well you know that is wrong". However that argument is true for all n as well. No matter what value of n you pick the numbers work out identically, yet these choices are "wrong", no matter the math. Tautologies are useless: 1=1 for all values of n as well. It tells you nothing. Neither does the Doomsday Argument. So wait, why all the argument: This is really an argument about anthropics more than reality. The issue is to pick a particular value of n and then pretend that that value of n is important. When you point out the absurdity of doing so, arguments quickly change. For instance in one paper they turned it on its head and said that selecting n+1 is no good because it's even more unlikely to be the last person on earth. Not that this is an entirely different argument. The arguments all seem to follow this pattern (at least the 1/2 dozen I've seen). When presented by the problem of picking an n, the arguments all then turn to various suggestions as to why n has to be a particular value, one that is today's value. I reject all such arguments as a preferred frame. Nature aborhs them.
marbles I guess I am a little old fasion too, to believe in the inevitable demise of our species is incomprehensible, to believe that we will realize our shortcomings and save the planet that we should cherish is more my speed. We are part of the aquarion age, we have the power and knowledge to survive. We will do so by one mind at a time.
Doomsday & Carter :m: Wow. Cool site!! So many others out there. To Arto (and others)...reading Baxter's Time at the moment. Actually read Origin first - fascinating!!!!! - makes you wish the Neanderthals had survived...then again, maybe they're better off where ever they are now. I know little about probability and less about Bayes, etc. My addled brain is still trying to cope with marbles in boxes - sometimes I see the intuition in the argument, then it gets lost. On a completely intuitive level (since I can't really get my head around this yet), I still feel there is something flawed about the assumptions. For example, wouldn't the same game/argument be relevant to a farmer on the banks of the Euphrates 1,000 years ago? Or a Roman brothel keeper in 250 BC? Eve whose mitochondrial appears to be in all our genes (yes, at some level, Bush and Sadam are related.............ewwwwwwwwwwww!!!!!)....couldn't she have pondered a similar relevance. Its intriguing, and I sense a certain truth in its simplicity, but would it be relevant to suggest that the white marble does not represent you or me. After all, we really are quite insignificant - not in terms of our sentience, but in terms of our mortal frail shell. What if the marbles represented something else? I've no real idea yet....maybe distinct steps/stages/jumps/mutations in our evolution as a species, or some other marker - maybe even stages in the universe's evolution. Some species have mutated rapidly and often, to an early extinction - some much slower, or with much fewer changes, but with a similar demise. Others have achieved a stasis and successfully remained, relatively unchanged, to the present. Others mutate at distinct intervals, often in a response to climate change or some other macro-variables. God this hurts my head.
