Hal wrote: > Jonathan Colvin writes, regarding the Doomsday argument: > > There's a simple answer to that one. Presumably, a million > years from > > now in the Galactic Empire, the Doomsday argument is no longer > > controversial, and it will not be a topic for debate. The > fact that we > > are all debating the Doomsday argument implies we are all > part of the > > reference class: (people debating the doomsday argument), and we > > perforce can not be part of the Galactic Empire. > > Well, I don't want to open up discussion of the DA. Suffice > it to say that good thinkers have spent considerable amounts > of time considering it and don't necessarily think that this > reply puts it to bed. > http://www.anthropic-principle.com has an exhaustive discussion.
Since it is coming from Nick B., over-exhaustive :) I don't think anybody, Nick included, has yet come up with a convincing way to define appropriate reference classes. Absent this, the only way to rescue the DA seems to be a sort of dualism (randomly emplaced souls etc). > [Regarding measure and size] > > > I find these conclusions counter-intuitive enough to suggest that > > deriving measure from a physical fraction of involved reasources is > > not the correct way to derive measure. It is not unlike trying to > > derive the importance of a book by weighing it. > > Don't be too eager to throw out this concept of measure. It > is fundamental to the Schmidhuber and Tegmark approach to the > multiverse. > It allows deriving why induction works as well as Occam's razor. > It explains why the universe is lawful and has a simple description. > It allows us in principle to calculate how likely we are to > be in The Matrix or some such simulation vs a basement-level > universe. It is quite an amazing quantity of results from > such a simple assumption. > I don't think you will find anything else like it in philosophy. > > As far as the specific issue of measure and size, suppose you > agree that making copies of a structure increases its > measure, but you object to the idea that scaling up its size > would do so. Years ago I came up with a thought experiment > that adopted the position you have, that size doesn't matter. > (That's what my wife kept telling me, after all...) From > that I proved that copies didn't matter either, which wasn't > too appealing. Today I would say that my premise was wrong. > Size matters. Isn't there a counter argument, though? Imagine a Universe of size X, and that observers have size Y<X. As Y increases towards X, the number of possible observers in the Universe decreases, until at the limit Y=X a universe can contain only one observer. Conversely, the smaller the Y, the more observers the universe can contain (and presumably the larger the measure). On this argument, *decreasing* our size should increase our measure (in the same way that smaller universes have greater measure). Jonathan Colvin
