Well, hmmm. I wonder if this qualifies as "stupid".
Could someone help me summarize the evidence for MWI in the quantum physics sequence? I tried once, and only came up with 1) the fact that collapse postulates are "not nice" (i.e., nonlinear, nonlocal, and so on) and 2) the fact of decoherence. However, the following quote from Many Worlds, One Best Guess (emphasis added):
The debate should already be over. It should have been over fifty years ago. The state of evidence is too lopsided to justify further argument. There is no balance in this issue. There is no rational controversy to teach. The laws of probability theory are laws, not suggestions; there is no flexibility in the best guess given this evidence. Our children will look back at the fact that we were STILL ARGUING about this in the early 21st-century, and correctly deduce that we were nuts.
Is there other evidence as well, then? 1) seems depressingly weak, and as for 2)...
As was mentioned in Decoherence is Falsifiable and Testable, and brought up in the comments, the existence of so-called "microscopic decoherence" (which we have evidence for) is independent from so-called "macroscopic decoherence" (which -- as far as I know, and I would like to be wrong about this -- we do not have empirical evidence for). Macroscopic decoherence seems to imply MWI, but the evidence given in the decoherence subsequence deals only with microscopic decoherence.
I would rather not have this devolve into a debate on MWI and friends -- EY above to the contrary, I don't think we can classify that question as a "stupid" one. I'm focused entirely in EY's argument for MWI and possible improvements that can be made to it.
From the Wikipedia fined-tuned universe page
Mathematician Michael Ikeda and astronomer William H. Jefferys have argued that [, upon pre-supposing MWI,] the anthropic principle resolves the entire issue of fine-tuning, as does philosopher of science Elliott Sober. Philosopher and theologian Richard Swinburne reaches the opposite conclusion using Bayesian probability.
(Ikeda & Jeffrey are linked at note 21.)
In a nutshell, MWI provides a mechanism whereby a spectrum of universes are produced, some life-friendly and some life-unfriendly. Consistent with...
This is for anyone in the LessWrong community who has made at least some effort to read the sequences and follow along, but is still confused on some point, and is perhaps feeling a bit embarrassed. Here, newbies and not-so-newbies are free to ask very basic but still relevant questions with the understanding that the answers are probably somewhere in the sequences. Similarly, LessWrong tends to presume a rather high threshold for understanding science and technology. Relevant questions in those areas are welcome as well. Anyone who chooses to respond should respectfully guide the questioner to a helpful resource, and questioners should be appropriately grateful. Good faith should be presumed on both sides, unless and until it is shown to be absent. If a questioner is not sure whether a question is relevant, ask it, and also ask if it's relevant.