Airports have a strange atmosphere. I frequently receive emails from friends who sit at airports, and contemplate their lives, go into philosophical meditations about the meaning of reality, or the mystery of our existence. Yesterday, I was stuck on such a meditation place, even worse, I was stuck there with nothing else to read but Susskind's book, "The Cosmic Landscape".
The last dinners I had in the company of physicists inevitably ended up with a discussion of the anthropic principle. At which point I very suddenly got very tired and left early. Being asked recently for my opinion on the matter I said I have none. As Stefan told me, that's not good, I am supposed to have an opinion about everything! No matter if it is a sensible one.
To get to my opinion or it's absence, let me introduce you to Oliver. I got to know Oliver as 'Olli_6703' in some online discussion around 2001. Since then he lost his job, his long-time girlfriend, an had an unfortunate accident that left him with a permanent limp. By now he is an alcoholic. I guess, drinking is his way to arrange himself with the insight that life sucks.
It's hard to say why he ended up like this. He's been very sportive, and suddenly being confined to slow-motion was really tough on him. It might also have mattered that his girlfriend did better in her job than he did, and she chose to live alone instead of with him - something he repeated endlessly and was unable to understand. Had she cheated on him and moved in with someone else it might have made more sense to Olli. But she stayed ALONE! Or then why did he have to loose his job in the first place, which started the whole series of unfortunate events? The company he worked for installed phone systems. They went broke cause the companies that were in need of these systems went broke. I am neither a therapist, a sociologist, nor an economist and don't know what the reason is. Maybe it's "just" the genes.
Sorry for the sad story.
Now imagine you are an atom in one of Olli's liver cells. You are a smart atom and have figured out the Standard Model. You had no need for some weird assumption like gravity, but you have found very elegant laws that describe the exchange of molecules in you cell. You even managed to measure the extension of the liver! To your very surprise you found that it has been growing recently. You and the other atoms are very puzzled by this, and you try to come up with a theory to explain it.
Maybe you introduce some a-essence that causes the liver to grow, but where does it come from and why has it only become important recently? Some of your colleagues have suggested that there are other meta-livers outside yours which obey different laws, but hey, you are a serious scientist, and that's just too weird. Besides this, it doesn't really explain anything. Some insist on a fourth force, based on some kind of a principle (you keep forgetting the name). But this force would only be important on completely unobservable distance scales. Though they claim it's important for a theory of everything you fail to see the point. Some even work on an extension of this theory that implies that the cosmos is nothing but a braid, but you can't really follow their arguments.
Then there are some others who found a beautiful string-like winding structure which they claim contains all the information necessary to explain the liver and probably more! But they are unable to predict anything from it. They keep repeating it's elegant, and keep making conjectures about things they don't even know what they are.
However, none of these incredible theories was able to help you understanding the strange place that you live in. Recently, it's been dubbed a crisis in liver-physics.
How smart has the atom to be to imagine the existence of a human being? To imagine several billions of them? Of the world they live in? With all the global and sociological problems? How smart has the atom to be to imagine the existence of the earth, the solar system, our galaxy, the universe, or even multiverses? The poor atom was just looking for a theory of everything, just some few equations that extend the Standard Model such that they explain the observed liver growth.
To come back to the anthropic principle: It is certainly right, if we weren't here then we wouldn't worry why we are here. But I am a physicist because I hope that I can understand at least part of the games that nature is playing on us. Retreating to the anthropic principle means to me to give up the believe that there is something to understand.
Maybe I am just just stubborn.
But I am surprised that just because we currently can not imagine a way out of the so-called 'crisis' in theoretical physics, so much effort goes into explaining why we can't explain what we want to explain. So much time goes into arguing why we can't argue. And smart physicists declare bugs to features, instead of looking for other ways to find insights.
Needless to say, I believe that there is a reason why the universe is the way it is. It might just be very hard to find. Try to imagine there is an universe in every gluon, and our universe is a gluon in an atom in some liver-cell of an alcoholic cosmic terrorist, who aligns his angular momenta on the axis of evil while his followers are forcing cosmological natural selection on innocent citizens.
I would rather come to the (admittedly depressing) conclusion that the human mind just might not be able to solve the problems we are currently facing, than being satisfied with the statement that there is nothing to explain. Going anthropic is not a solution to anything. If anything it's reason to quit physics.
Fortunately, it is in the nature of human beings to never be satisfied. Therefore, I have no doubt that this crisis is temporarily.
That's the reason why I don't spend time on thinking about the anthropic principle and the meaning of the string landscape, not even at airports. There are just more interesting topics.
(Like, where is the next Starbucks, and what do the Americans do with their milk foam without spoons?)
See also Alejandro's recent post about the lamdscape.