# A completely brilliant and readable 200

A completely brilliant and readable 2009 paper by Max Tegmark, explaining why we now think that parallel universes are real.

http://arxiv.org/abs/0905.1283v1

"If there are indeed many identical copies of you, the traditional notion of determinism evaporates. You could not compute your own future even if you had complete knowledge of the entire state of the multiverse, because there is no way for you to determine which of these copies is you (they all feel they are). All you can predict, therefore, are probabilities for what you would observe. If an outcome has a probability of, say, 50 percent, it means that half the observers observe that outcome."

His 2001 paper gives more background on how the idea that waveforms 'collapse' when observed has come to be replaced by that of 'decoherence' (no observer required):

http://arxiv.org/abs/quant-ph/0101077

http://arxiv.org/abs/0905.1283v1

"If there are indeed many identical copies of you, the traditional notion of determinism evaporates. You could not compute your own future even if you had complete knowledge of the entire state of the multiverse, because there is no way for you to determine which of these copies is you (they all feel they are). All you can predict, therefore, are probabilities for what you would observe. If an outcome has a probability of, say, 50 percent, it means that half the observers observe that outcome."

His 2001 paper gives more background on how the idea that waveforms 'collapse' when observed has come to be replaced by that of 'decoherence' (no observer required):

http://arxiv.org/abs/quant-ph/0101077

### [0905.1283v1] The Multiverse Hierarchy

Shared with: Public

+1'd by: Paul Pakozdi

*This post was originally on Google+*