The political campaign for the multiverse continues today with a piece by Amanda Gefter at Nautilus. It’s a full-throated salvo from the Linde-Guth side of the multiverse propaganda war they are now waging, with Linde dismissing Steinhardt’s criticism as based on “a total ignorance of what is going on”. All of the quotes for the article are on the pro-multiverse side. There is a new argument from them I’d never heard before: Guth comes up with this one:
You can create a universe from nothing—you can create infinite universes from nothing—as long as they all add up to nothing. Not only is that a deep insight, it also creates a testable prediction. “Eternal inflation certainly predicts that the average density of all conserved quantities should be zero,” Guth says. “So if we ever became convinced that the universe has a nonzero density of electric charge or angular momentum, eternal inflation would no longer be an option.”
The article is subtitled “Why the majority of physicists are on one side of a recent exchange of letters”. One way to interpret this claim is just that 33 is more than 3, but the reason for this is clear: while Guth, Kaiser, Linde and Nomura decided to go on a political campaign, drumming up signatures on their letter, Ijjas, Loeb and Steinhardt didn’t do this, but instead put together a website discussing the scientific issues.
Where the majority of physicists stand on the Guth-Linde claims is an interesting question, one that I don’t think is addressed anywhere by hard numbers. My anecdotal data is that the majority of those I’ve ever talked to about this don’t think the Guth-Linde multiverse claims are science, but don’t see any reason to waste their time arguing with pseudo-science. They hope it will just go away by itself, as it becomes ever clearer that the multiverse is, scientifically, an empty idea.
Unfortunately, I don’t see this going away and I think it’s now doing very serious damage to physics and its public image. There’s a political campaign now being waged, and one side is very determined to win and putting a lot of energy into doing so. Those on the other side need to step up and make themselves heard.
Update: Guth and Linde brought their publicity campaign to New York this past Saturday (video here) where they told a large World Science Festival audience that string theory is beautiful, it predicts the multiverse, inflation has made lots of predictions that have all worked out, and they have (more or less…) the full theory that does all this wonderful stuff. Nothing from them about any thing less than utterly glorious and well-defined about the string theory landscape/eternal inflation product they were pushing. Also on the panel were three philosophers (Jim Holt, David Albert and Barry Loewer) who did an admirable job of trying to push back by pointing out obvious inconsistencies. They at least got Guth and Linde to admit that there was this “measure problem” thing still to be fixed. Physics is in a very weird state indeed now that physicists have adopted untestable metaphysical speculation as their program, with philosophers the ones trying to engage in more normal scientific practice.
There was one multiverse skeptic, George Ellis, who unfortunately didn’t engage with this and was diverted onto other topics. One string theorist was there (Veronika Hubeny), who explained about AdS/CFT duality, without anybody bringing up the fact that this has nothing at all to do with what Guth and Linde were promoting in the rest of the discussion.