sábado, junho 23, 2018

Implausifiability in Physics: “Lost in Math - How Beauty Leads Physics Astray” by Sabine Hossenfelder

“The time it takes to test a new fundamental law of nature can be longer than a scientist’s career. This forces theorists to draw upon criteria other than empirical adequacy to decide which research avenues to pursue. Aesthetic appeal is one of them. In our search for new ideas, beauty plays many roles. It’s a guide, a reward, a motivation. It is also a systematic bias“

In “Lost in Math - How Beauty Leads Physics Astray” by Sabine Hossenfelder

One of the most obnoxious notions I’ve ever read in Physics is the one that purports that we’re a simulation. If it's all a simulation, why wouldn't the world that simulated us be a simulation too? This is the turtles all the way down idea. This doesn't mean it isn't true but it's also the same question as, if God created the universe and us, who created God? The answer I sometimes get when I say it’s all hogwash, is that the theory is aesthetically pleasing. Where is the evidence? And more importantly, is it “implausifiable” (I’m borrowing here Hossenfelder’s term)? The supposed evidence for our universe being a simulation seems to largely include the idea that if we extrapolate our technological progress further ahead in time, we will be able to build such a simulation ourselves *therefore* we are a simulation. That's not a very good argument for a lot of reasons. First, how do we know there aren't hard blockers that prevent us from ever getting to the point in our technology to actually build a simulation equal to the world we live in? Of course those blockers might be because we are in a simulation. But like string theory, you might have a theory of everything but if it can't predict anything, its utility is questionable without some other actual theory that predicts things in a testable way.

But in actually thinking about this idea (I always do this thinking before my morning bowel movement), the one word that best describes the world we live in is "lazy". It answers why water doesn't go uphill, why everything seems to submit to math, even quantum mechanics and the weird observer question. The answer is, if you are lazy, why bother to do something unless you have an observer or something that impacts an observer in some manner? Why bother building other galaxies when you can just show them to us as photons of light? Why bother actually building Mars until humans bother to send spacecraft there?

If I were programming our universe, a computer language with lazy evaluation would be ideal. Write the whole thing out but only actually calculate each function when it is actually needed. We could be living in a Haskell REPL and God could be having fun making changes at the command line. Of course the full Schrödinger equation is rather complicated so perhaps our universe could be termed "mostly lazy". Make it complicated enough to confuse us with a dazzling array of possibilities but down deep, lazy. At this point, even entropy is reduced to a notion of laziness, the glass shatters on the floor but it never fixes itself and returns to its original form because that would be too much bother.

Why do physicists embark on the “Aesthetically-Pleasing-Bandwagon”? Because Physicists belong to the Human Race (at least some of them do). I think it’s due to the human need to believe in an ordered universe. It's all part of our pattern-finding instinct that lets us turn separate flashes of colour into a tiger hiding behind some trees. It can be very useful, this desire to provide simple, aesthetically and pleasing explanations. We get chemically rewarded when we make links, so we feel satisfied when we identify a tiger and successfully run away. Unfortunately, we also feel satisfied when we make a wrong link, as long as it doesn't eat us. Hence a String Theory (the TOE of all answers), provides the same three-letter answer for pretty much anything and everything (TOE that is). The same goes for the Multiverse. Fortunately, some people are less than satisfied by this. We call these people "well-grounded physicists". In millennia gone by they would all probably have been eaten by tigers while they checked the rigour of their solutions. It might be a tiger, or a series of birds, or possibly some oranges carefully positioned, so what I am calling for is more research into... chomp!
If the universe is simple, as it was for early man, simple answers will do. Now we know it to be more complicated, we need better answers than just yelling "Tiger!" every time we see something orange. Sabine says: “Since Pauli's days, postulating particles has become the theoretician's favorite pastime. We have preons, sfermions, dyons, magnetic monopoles, simps, wimps, wimpzilla, axions, flaxions, erebons, cornucipons, giant magnons, maximons, macros, branons, skyrmions, cuscutons, planckons, and sterile neutrinos – just to mention the most popular ones. We have unparticles. None of thse has ever been seen, but their properties have been thoroughly studied in thousands of published research articles.”  It’s quite a jungle. General Relativity was invented based on facts that were already known for a long time and it opened doors to new insights. What Einstein did is play with ideas to come up with something unique. In that sense if you let more people play with ideas on what the Vacuum is made of connected to how the Higgs Field works and how Dark Matter works, doing (thought) experiments with something like granular and CFD simulators than 'something' interesting might pop up. What the LHC is doing is like sifting through the desert to gain an important clue of what 'sand' is, while with simulations you can explore the idea of grains and interactions on a whole new level, we already know almost everything there is to know and can find out with these machines. Now with powerful supercomputers we have a chance to play with as many different kind of simulations we like, this is the new world that is opening up and new to explore, and where we should focus on.

Bottom-line: “Physics isn’t math. It’s choosing the right math”. I fully agree with Hossenfelder. What a load of BS what’s happening in the world of Physics nowadays. This is nothing more than a pack of hack physicists trying to explain what they can't understand with absurd fantasies just to justify tenure. I like the proverbial analogy with Copernicus, which alludes to certainty to give a modicum of credibility to their erroneous reasoning. If I can rip holes in these absurd claims, anyone can. The people who make them have below average intelligence; real not simulated. Billions of weirdos and thickos think otherwise...Who cares!

3 comentários:

Luís Filipe Franco disse...

About the simulation hypothesis there is a very good on the subject:
Simulation https://g.co/kgs/PPd3D4


Peter D. Tillman disse...

Re: simulations and other untestable hypotheses (string theory!):
“Who gives a fuck what you like or dislike? Nature doesn’t care”— this is hotshot physicist Nima Arkani-Hamed. I love her interviews!

Be sure to read Peter Woit's, if you haven't seen it:

Manuel Antão disse...

Thx for the heads-up Peter. I wasn't aware of this. I only read Woit's book "Not Even Wrong" where he bashes String Theory.

The interviews in Hossenfelder's book are one of the most interesting aspects.

Harkani-Hamed along with David Wallace are two of the main proponents of MWI of Quantum Mechanics: