How Popper Killed Particle Physics

Popper, upside-down.
Image: Wikipedia.

Popper is dead. Has been dead since 1994 to endure precise. But also his philosophy, that a scientific thought needs to endure falsifiable, is dead.

And luckily so, because it was utterly impractical. In practice, scientists can’t falsify theories. That’s because whatever theory tin endure amended inward hindsight hence that it fits novel data. Don’t gyre your eyes – updating your noesis inward response to novel information is scientifically solely audio procedure.

So, no, you lot can’t falsify theories. Never could. You could yet jibe planetary orbits amongst a quadrillion of epicycles or invent a luminiferous aether which but precisely mimics special relativity. Of course of teaching no ane inward their right heed does that. That’s because repeatedly fixed theories leave of absence hideously difficult, non to cite hideous, period. What happens instead of falsification is that scientists transition to simpler explanations.

To endure fair, I intend Popper inward his later on years backpedaled from his early on theses. But many physicists non only yet believe inward Popper, they also opportunistically misinterpret the master Popper.

Even inward his worst moments Popper never said a theory is scientific but because it’s falsifiable. That’s Popper upside-down together with clearly nonsense. Unfortunately, upside-down Popper directly drives theory-development, both inward cosmology together with inward high unloose energy physics.

It’s non hard to come upwards up amongst theories that are falsifiable but non scientific. By scientific I hateful the theory has a reasonable run a peril of accurately describing nature. (Strictly speaking it’s non an either/or criterion until ane quantifies “reasonable chance” but it volition suffice for the acquaint purpose.)

I may predict for example, that Donald Trump volition endure shot past times an elderly lady earlier his commencement term is over. That’s compatible amongst acquaint noesis together with totally falsifiable. But chances it’s right are basically cypher together with that makes it a prophecy, non a scientific theory.

The thought that falsifiability is sufficient to brand a theory scientific is an declaration I listen often from amateur physicists. “But you lot tin attempt it!” they insist. Then they explicate how their theory reworks the quantum or what lead keep you. And post service their insights inward all-caps on my time-line. Indeed, every bit I am writing this, a comment comes in: “A practiced thought demand only endure testable,” says Uncle Al. Sorry, Uncle, but that’s rubbish.

You’d intend that scientists know better. But ii years agone I sat inward a speak past times Professor Lisa Randall who spoke well-nigh how nighttime thing killed the dinosaurs. Srsly. This was when I realized the real same error befalls professional person particle physicists. Upside-down Popper is a widely-spread malaise.

Randall, you lot see, has a theory for particle nighttime thing amongst approximately interaction that allows the nighttime thing to clump inside galaxies together with shape disks similar to normal matter. Our solar system, hence the idea, periodically passes through the nighttime thing disk, which together with hence causes extinction events. Or something similar that.

Frankly I can’t retrieve the details, but they’re non hence relevant. I’m but telling you lot this because someone asked “Why these nighttime thing particles? Why this interaction?” To which Randall’s answer was (I paraphrase) I don’t know but you lot tin attempt it.

I don’t hateful to alternative on her specifically, it but hence happens that this speak was the instant I understood what’s incorrect amongst the argument. Falsifiability lone doesn’t brand a theory scientific.

If the only declaration that speaks for your thought is that it’s compatible amongst acquaint information together with makes a testable prediction, that’s non enough. My thought that Trump volition acquire shot is totally compatible amongst all nosotros shortly know. And it does brand a testable prediction. But it volition non come inward the annals of science, together with why is that? Because you lot tin effortlessly arrive at approximately meg similar prophecies.

In the foundations of physics, compatibility amongst existing information is a high bar to jump, or hence they wish you lot to believe. That’s because if you lot laid upwards a novel theory you lot commencement lead keep to reproduce all achievements of the already established theories. This bar you lot volition non confine unless you lot genuinely empathise the acquaint theories, which is why it’s security to ignore the all-caps insights on my timeline.

But you lot tin acquire how to confine the bar. Granted, it volition accept you lot a decade. But after this you lot know all the contemporary techniques to mass-produce “theories” that are compatible amongst the established theories together with brand eternally amendable predictions for hereafter experiments. In my upcoming book, I refer to these techniques every bit “the hidden rules of physics.”

These hidden rules tell you lot how to add together particles to the touchstone model together with and hence acquire inward hard to mensurate them, or add together fields to full general relativity together with and hence explicate why nosotros can’t encounter them, together with hence on. Once you lot know how to do that, you’ll confine the bar every time. All you lot lead keep to do together with hence is twiddle the details hence that your predictions are but well-nigh to leave of absence measureable inward the next, say, five years. And if the predictions don’t operate out, you’ll fiddle again.

And that’s what most theorists together with phenomenologists inward high unloose energy physics alive from today.

There are hence many of these made-up theories directly that the chances whatever ane of them is right are basically zero. There are infinitely many “hidden sectors” of particles together with fields that you lot tin invent together with and hence pair hence lightly that you lot can’t mensurate them or brand them hence heavy that you lot demand a larger collider to arrive at them. The character criteria are incredibly low, getting lower past times the day. It’s a race to the bottom. And the bottom mightiness endure at asymptotically minus infinity.

This overproduction of worthless predictions is the theoreticians’ version of p-value hacking. To acquire away amongst it, you lot but never tell anyone how many models you lot tried that didn’t operate every bit desired. You fumble things together until everything looks dainty together with and hence the community volition approve. It’ll acquire published. You tin give talks well-nigh it. That’s because you lot lead keep met the electrical flow character standard.  You encounter this laissez passer on off both inward particle physics together with inward cosmology and, to a greater extent than recently, also inward quantum gravity.

This nonsense has been going on for hence long, no ane sees anything incorrect amongst it. And regime annotation how real similar this is to the dismal province of affairs inward psychology together with the other life-sciences, where abusing statistics had leave of absence hence mutual it was but normal practice. How long volition it accept for theoretical physicists to acknowledge they lead keep problems too?

Some of you lot may retrieve the volume of philosopher Richard Dawid who claimed that the absence of alternatives speaks for string theory. This declaration is incorrect of course. To get amongst at that topographic point are alternatives to string theory, but that Richard conveniently doesn’t hash out them. But what’s to a greater extent than of import is that at that topographic point could endure many alternatives that nosotros do non know of. Richard bases his arguments on Bayesian reasoning together with inward this instance the unknown issue of unknown alternatives renders his no-alternative declaration unusable.

But a variant of this declaration illuminates what speaks against, rather than for, a theory. Let me telephone telephone it the “Too Many Alternatives Argument.”

In this declaration you lot don’t wish to demonstrate that the probability for ane special theory is large, but that the probability for whatever special theory is small. You tin do this fifty-fifty though you lot yet don’t know the full issue of alternatives because you lot know at that topographic point are at to the lowest degree every bit many alternatives every bit the ones that were published. This probabilistic approximate volition tell you lot that the to a greater extent than alternatives lead keep been found, the smaller the chances that whatever ane of them is correct.

Really you lot don’t demand Bayesian mysticism to encounter the logic, but it makes it audio to a greater extent than sciency. The betoken is that the easier it is to come upwards up amongst predictions the lower their predictive value.

Duh, you lot say. I listen you. How come upwards particle physicist intend this is practiced scientific practice? It’s because of upside-down Popper! They brand falsifiable predictions – together with they believe that’s enough.

Yes, I know. I’m good on the means to brand myself the most-hated somebody inward high unloose energy physics. It’s no fun. But look, fifty-fifty psychologists lead keep addressed their problems past times introducing ameliorate character criteria. If they tin do it, hence tin we.

At to the lowest degree I promise nosotros can.