When Chad first asked me to guest blog here, my first response was that I didn't have anything to say. After a little thought, however, it occurred to me that this would be an opportunity to do a little exposition. Unfortunately, my research area is quite a bit on the esoteric side, so I had to look elsewhere for possibilities. Thus, the "ask a string theorist" post below. But, the next thing that occurred to me was to talk about multiple universes.
Why do that? Not because I believe that it's central to string theory, and not because I believe that it's even necessarily science. What I do believe is that it's already in the public sphere, that the public finds it interesting, and that there's a lot of misinformation out there about it. It is a controversial topic, and unlike many of the controversies that apparently will flow from even the most innocuous string theory post, maybe I have something to say that the general public hasn't heard yet. At the very least, if I have my say here, I never have to speak on this subject again.
So, an apology. To the readers of this blog, I apologize for the mess that I'm sure the upcoming comment threads will become. I apologize for the distortions, elisions and simplifications in my posts. I apologize if I give the impression that this is something that most scientists spend a lot of time on -- it isn't. I apologize if you think that I am stating outright that this is either all physics or all philosophy -- you get to make those decisions yourself.
To my colleagues, I apologize for not including citations. Given the controversial nature of the subject, the strong feelings it evokes and the danger inherent in my spotty memory, I thought it best to keep things nameless. This way all the blame falls on me. Most of the thoughts presented here have arisen in various dinner table and office conversations over the past few years. I've tried to present the other side as best I can, but my beliefs do come through fairly strongly by the end.
With any luck, I've managed to write something that will alienate everyone involved. I hope you find it interesting. I promise to be much more boring in the future.
I counted 7 'apology' or 'apologize' in your post. I am sorry, but this is hardly enough and I am also not really sure if you are sincere 8-)
First, how many solutions are there currently thought to be in the Landscape?
I've seen these 3 values a lot in the literature:
Secondly: Why are the many science fiction stories and novels about the Multiverse different from what String Theory tells us?
Thirdly: how well are actual anlyses of data (WMAP etc) doing at defining WHICH universe we happen to inhabit?
Fourth: The Axis of Evil. Real, or artefact?
No need to apologize, I was just expressing personal frustration (again). Just to clarify, I don't mind discussions of "is the multiverse science" every now and then, or discussion of "is string theory bullshit" every now and then, I am perfectly capable of ignoring those... I just wish we could have other discussions as well occasionally, ones of specific and concrete topics that are actually related to string theory. I'd enjoy those more, we'll see less messy comment threads and less of the day-after hand wringing and heavy sighing the string theory threads usually lead to. I have great hope for the more "boring" topics you mentioned, I'll have less rant-like comments there...
Just to clarify, I don't mind discussions of "is the multiverse science" every now and then, or discussion of "is string theory bullshit" every now and then, I am perfectly capable of ignoring those... I just wish we could have other discussions as well occasionally, ones of specific and concrete topics that are actually related to string theory.
Personally I'm rather looking forward to this in the hopes that it will offer us a chance to see the landscape/multiverse concept explained in actually somewhat concrete terms rather than being "debated" as some kind of sociology-of-science trend. In awfully easy to find arguments for and against the "landscape", but surprisingly hard to find a clear explanation of how it's supposed to actually work...
I totally agree with you. In fact my simple question can be summed up in the following.
First let's assume that string theory and the landscape are correct in describing "our verse". Now any "intelligent being" in another verse would also eventually conclude the same based on experimental and/or observational data or mere conjecture. (Note: The idea that intelligent beings in another verse must be like us would seem to be in totally contradiction with the idea of the landscape. We are looking for the vacuum state that defines OUR verse not someother verse for which we have exactly no knowledge whether it can or cannot support "intelligent life".)
If these other beings are to also draw the same conclusions that we do then there must exist some common physical principles in all verses capable of supporting intelligent life. I am asking simply: What are these basic physical principles and what evidence do we have for them?