Quote:
|
Originally Posted by grant hutchison
No, the low probabilities don't multiply as you're suggesting.
Each new generation has a new piece of information (their own existence) and therefore redoes the calculation, coming up with a new 5% and 95% confidence interval.
Grant Hutchison
|
But for the Carter catastrophe to be correct, you could take an imaginary 1 million species to start with. After 1 generation, only X (let's say 100,000) would still exist. Of those, 20,000 gets to a third generation, and perhaps 5,000 to a fourth one, and so on. So the chance that we have reached here is of course 100%, but the chance that
a first generation species has survived as long as we did is 1 in 1,000,000 (random number, again). So it is much more amazing that we exist, according to the same hypothesis, than it is to suppose that we will exist for a very long time afterwards...
Another criticism / point of view. An alien visits the earth, and sees just one generation of people. The chance that it sees us is bigger if only a few more generations will survive than if we will live for millioàns of generations (thus far, standard Carter). Now take the opposite view. An alien comes to the earth, and sees another generation than us. The chance of this happening is much bigger the more generations there are, and much smaller if only a few generations are to come. So when you take the starting position that the alien has picked another generation (and this one is equally valid as the supposition that he has picked us), the chance of a long survival is actually bigger than the chance of a short survival.
A nice statistical paradox!