Thursday, 6 June 2013

The Universe is fine, thanks.

I am considered neither a high-profile theoretical physicist nor a leading figure in my area, but I do consider myself a theoretical physicist with enough knowledge to weight in some rational thoughts even against the strongest authority arguments.

You have no idea of why I am moaning like that, so let me explain the reason of my indignation. I have just read the following article from Scientific American, which I consider to be a rather good popular science magazine:

It's true that the article is originally from the Simmons Foundation, but SA published it anyway.

Well, now I am going to say what pisses me off in this article. A fair summary would be that it is nothing more than a desperate and kind of arrogant attempt to justify something that should not be a worry at all in science: our own ignorance.

The article starts with a quote from Nima Arkani-Hamed, a high-profile theoretical physicist (have I said already that I hate authority arguments?). At a conference he said that the "universe is impossible". In support, some other high-profile physicists (!) give their statements as well.

Their arguments go like that. All accessible experiments up to date confirm the Standard Model in its pre-string/supersymmetry form with reasonable accuracy. There is, however, a lot of unexplained things. Because the only explanations we could think about do not work, we must assume that the only solution is the multiverse hypothesis, where every kind of universe exists and we happen to be in one of them.

I'm being unfair, of course. The arguments are more complicated than that, but the essence is the same.

For instance, they all make a big deal about what we usually call "naturalness". Naturalness is not a rigid principle of nature, it's more like a hope. A hope that quantities appearing in Nature are not too strange for OUR taste. I guess you are all smart enough to recognise that the catch here is the fact that we are judging how Nature should behave by our standards of symmetry, which in the end is to what it boils down.

Then it comes a series of things that still are unanswered. For some reason, the argument again is that if we could not find a better solution, than the solution is a multiverse. That sounds like desperation to me. Can't we accept that maybe we still don't have enough data to understand the problems? Can't it be that we are missing something? That some of our ideas have problems and must be substituted to work? Of course it can.

There is something even crazier happening. Many versions of the multiverse idea are unfalsifiable. I said this many times and I will repeat it again. One unfalsifiable answer is as good as any other unfalsifiable answer. Be it the multiverse, god or the Matrix. 

Even those versions which are marginally falsifiable, if there is such a thing, are simply jokers. Once you postulate that there are any kind of universe, all problems of why the universe is like it is are solved. Here enters the probable human explanation for why this idea might be becoming so attractive to those who spent so much time trying to find a solution but didn't. If everything goes, it's not their fault that they haven't found one.

Like naturalness, the claims rely in even more concepts which are at best disputable. Take the idea that we live in an extremely unlikely universe as very few variations would support life. That is not true. If I put aside the fact that we have no real agreement about what we want to call "life", it would be fair enough to say that a universe in which anything that would look like a computer program could run would be able to support life. I can imagine an infinitude of variations of physics that keep the mathematics necessary for this to happen intact.

Of course the hypothesis can be true. Solipsism can be true as well. I can be the only thing that exists in the universe. Or maybe you. Shall I say that the current problems of physics support the solipsism idea? It surely can explain physics and a lot more...

Honestly, I didn't like the article at all. A similar thing happened about 110 years ago, although it was in the other side of the spectrum. Around 1900, Lord Kelvin, a high-profile physicist that we all know, said that we had the explanation for everything and that all that remained was some more precise measurements. There were only two insignificant problems to solve. As you know, their solution only reinstated the fact that Nature abhors authority arguments.

More than one century later, we know science and philosophy enough not to fall in the same kind of trap again. Still, humans have a hard time to admit failure even when it's definitely not their fault.

Meanwhile, the "impossible" universe goes on. Apparently, unworried about all the inconsistencies in all our descriptions of it. Thank you.

No comments:

Post a Comment