Since I just spent some of the morning not doing what I should have been doing, but reading about other things, in case you also want to do this, here are some options:
- I’m very excited to see an article at Smithsonian Magazine with the title Can Physicists Ever Prove the Multiverse is Real? (remember, answers always no to headlines). Unlike just about every other effort of this kind, the author (Sarah Scoles) brings up the obvious problems, quoting Carlo Rovelli:
Some theoretical physicists say their field needs more cold, hard evidence and worry about where the lack of proof leads. “It is easy to write theories,” says Carlo Rovelli of the Center for Theoretical Physics in Luminy, France. Here, Rovelli is using the word colloquially, to talk about hypothetical explanations of how the universe, fundamentally, works. “It is hard to write theories that survive the proof of reality,” he continues. “Few survive. By means of this filter, we have been able to develop modern science, a technological society, to cure illness, to feed billions. All this works thanks to a simple idea: Do not trust your fancies. Keep only the ideas that can be tested. If we stop doing so, we go back to the style of thinking of the Middle Ages.”
- John Horgan has a wonderful, very long, interview with Scott Aaronson. Highly recommended as a way to avoid work and learn all sort of interesting things from and about Scott, whose blog you should be reading anyway. If you want to discuss this, you likely can do so with the man himself here.
- If you just can’t get enough of the multiverse, there’s something else quite long available, a podcast of Sam Harris in conversation with Max Tegmark.
So in the Scoles piece Polchinski and Linde seem to argue that since the probability that everything comes out exactly the way it did in the universe, which makes life possible, is so low, there must be an infinite number of universes out there. Do they really not understand basic probability theory? Probability doesn’t apply to single instances. Not that way. Why exactly doesn’t anyone call them on this? Suppose you saw a random number generator, and you knew it generated numbers from 1 to 1000000. You see a 1 on it, does that tell you anything? No. It certainly doesn’t tell you that there must be millions of random number generators out there since you happen to live with the one which is showing a 1.
Jeffrey M.,
This is by now an ancient argument, I don’t see any possibility of anything new being said about it, so would like to discourage anyone who wants to carry it on. You need a larger framework than our current physics to make sense of any of these issues of what is likely and what isn’t. Linde et al. have one and are promoting it, the problem is that it’s an empty, untestable one. Rovelli is right that this is going back to pre-scientific styles of thinking.
A tiny correction: I guess ‘Every’ in the link to the article at Smithsonian Magazine should read ‘Ever’.
Now, if we could stop addressing the “Middle Ages” like an intellectual wasteland, that would be great.
John Fredsted,
Thanks, fixed.
L,
Good point. Whatever the failings of medieval theologians, I suspect they would have recognized the problems with multiverse explanations.
I don’t think that multiverse speculation is “an intellectual wasteland” a consequently I don’t agree that comparing the speculators to medieval thinkers implies that the pre-modern era was an intellectual wasteland. One needs only a nodding acquaintance with history to be aware that medieval thought was rich, varied, and intricate. Indeed, the usual complaint of the student is that it was all too intricate.
But the fact remains that there is a basic qualitative difference between scientific and non-scientific modes of thought, and that the multiverse falls on the non-scientific side of the line. This is not to say that pre-modern modes of thought have disappeared, nor that scientific thought has no medieval or indeed classical antecedents. But today we (ideally) prefer to make decisions with a mode of thought that was alien to our forbears.
I really like Ada Palmer’s treatment of this intellectual history in her “Sketched of a History of Skepticism” series (first post here: http://www.exurbe.com/?p=2725.)
The fact is that, despite the common conception, there’s more in the Middle Ages than theologians. Universities were born, with its basic curriculum centring on logic in the trivium and four mathematical disciplines on four in the quadrivium (arithmetic, astronomy, geometry and music, seen as applied proportions); people studied, even empirically, every area of “natural philosophy”; in physics we have medieval thinkers derive the basics of dynamics and kinematics, discovering results often attributed to Galileo and his peers, and inquire the possible motion of the Earth, in addition to refining astronomical models; and in general, these people laid the basis of the scientific method.
A good short introduction on the matter can be read here.
Peter,
I am a long time reader of yours, both your blog and the book,
and I am delighted to see your insistence on intellectual responsibility
is gaining traction. See for instance : https://arxiv.org/pdf/1604.06773
Keep up the good work, for science’s sake !
Denis