Saturday, February 23, 2019

Truth isn't the same as accessibility: a Columbus metaphor

Muhammad Nima has asked question that I have been asked 2,019 times (including cases when I was giving a popular lecture on string theory, and it was usually the first question) and I have answered it 1,212 times:
Dear Lubos, you say that "to kill a theory, one has to just falsify it", but how would you respond to those activists who say that for a theory to be real science, it must make predictions as well? The mere condition of a theory not being falsifiable doesn't make it science - then God is science - they say.
Clearly, the impact of my explanations has been close to zero. The laymen seem obsessed with this self-evidently wrong and irrational thesis. For a statement to be scientifically meaningful, there must in principle exist an operational procedure that produces the answer. But this test must only exist in principle and it is surely absolutely silly to require "more" than that. For example, unlike the existence of God, the existence of WIMPs that make up around 5% of the energy density of the Universe is undoubtedly a scientific question, whether or not we may observe the WIMPs in the next 100 years.



In particular, it is absolutely misguided to assume something like
The more easily a statement about science is testable, the more scientific it is.
I have always been flabbergasted by the stupidity of the people who apparently believe garbage of this kind – and the number of such people (people who can't understand why e.g. Peter Woit is just a pile of feces) is yuge, indeed.

Over the years, I have converged to a theory that all these people are basically generic members of the animal kingdom on par with cattle or something like that – they can't comprehend the concept of the truth in the logical, mathematical, or scientific sense. At most, "truth" is a concept that was described to them as "something good". But they don't understand in what sense it is "good". The only type of "good" they can understand are things like "how many steaks I will eat" (and "how quickly") and because "truth" is something "good", it must mean the same thing.



Well, it just doesn't mean the same thing. There is no equivalence – and no reliable correlation – between the ease or speed at which the truth may be discovered (I will call it "accessibility" but the quantity vaguely describes the "degree of testability or falsifiability" as well); and the truth itself. It's a fatal mistake to conflate the truth value of a well-defined abstract scientific proposition with the question "how useful something will be for my practical life".



To clarify the point on a really simple model, I will consider two situations, a modern scientific question and a question from the epoch of marine explorers. The modern situation will be all about WIMPs – which may be the lightest superpartners, LSPs, but they may be something else, too. The historical situation will be about the hypothesis that aside from the Old World (Eurasia plus Africa), there also exists at least one extra large continent on Earth that can easily host at least half a billion people.

OK, let's return before 1492 AD. You are a scientist who has some ideas and reasons to think that there should be an extra continent – just to be sure, you mostly believe that the Earth is round and you also have some reasonable enough ideas about its rough radius (but you can easily find people who disagree on one or both points). If you know the history, you would be a greater visionary than the people who were alive because e.g. Columbus thought he could only find a new trajectory to India. But you were smarter and thought about geology and stuff like that.
Intemezzo, CERN fun: CERN has recreated the first browser from 1990 that was running on NeXT. You may suffer and play with it right now; guide & story. The progress in 29 years was visible but... incremental.
There was no good reason why all the big continents should be clumped as the Old World, you suggested. There are probably other lands, this possibility surely deserves to be probed etc. If you follow me, there are lots of cute subtleties that are rather analogous in between the historical and present situation. In particular, you're not quite certain whether the new continents – or new particle species – exist at all. The geological or physical arguments about questions near the cutting edge tend to be non-rigorous or inconclusive – that's why they're the cutting edge. For example, now in the 21st century, you know that there has been Pangaea which merged almost all land masses. Similarly, it may happen that supersymmetry doesn't exist at any low energies – and only gets unbroken at the GUT scale or Planck scale. This may happen. But you also have pretty good reasons why you believe it seems relatively unlikely, both in the case of continents and the superpartners.

Fine, in the 15th century, you actually start to study this question somewhat more seriously. You get graduate students etc. They will bring you the following hypothesis how the new hypothetical continent, Trumpia, is far from Spain:
  • Trumpia is 30 km away
  • Trumpia is 300 km away
  • Trumpia is 3,000 km away
  • Trumpia is 30,000 km away
  • Trumpia doesn't exist or is so far that it's basically right to say that it doesn't exist
I decided to pick four positive options because slower schoolkids clearly like to repeat the same ideas with many new numbers and this repetition makes them think that they're learning new things. ;-) More intelligent readers are surely able to compress this blog post and rewrite some copies of sentences as unified propositions that involve the functional dependence etc.

I chose the distances to Trumpia because they may be directly mapped to the following hypotheses about the WIMP mass:
  • WIMP mass is 30 GeV
  • WIMP mass is 300 GeV
  • WIMP mass is 3,000 GeV i.e. 3 TeV
  • WIMP mass is 30,000 GeV i.e. 30 TeV
  • WIMP is so heavy that it's incompatible with the WIMP miracle, or it doesn't exist at all.
In both cases, you should agree that up to some very mild subtleties and inaccuracies in the definition, the division to the groups is basically well-defined. Some new continents – e.g. if they're defined as landmasses of areas exceeding some lower bound, and perhaps with extra conditions on the tectonic plates etc. – either exist or don't exist. Similarly, WIMPs exist or don't exist. With some really powerful ships or detectors that you may imagine to exist in 500 or 50,000 years from now, it's possible to decide.

That's how continents and new particles differ from God. You have an argument that the test could be actually done in the real world – but not in the case of God. However, you don't actually need to perform this test for the argument to be valid. The theoretical argument that the test is possible in principle is absolutely sufficient to prove that the statement is scientifically meaningful.



The Brandenburg Gate is accessible by wheelchairs which doesn't mean that it's the most attractive sightseeing in the world.

Back to the 15th century. Are the possible answers about the existence and distance of Trumpia (from Spanish beaches) scientific and equally scientific? And are they equally likely? Should we treat them very differently?

Note that the different positive answers have very different practical consequences. If Trumpia exists and is 30 km away, it means that good swimmers may really swim there. That's not bad. Just be bold, take some weapons with you, swim in the direction of Manhattan, Trumpia, and after 30 km of swimming, you may conquer a pretty good island that will be relatively valuable shortly.

If the distance is 300 km, swimming could be hard but a boat could be enough. With 3,000 km, you need some pretty good ships, let's call them Santa Maria. If it's 30,000 km (and this option is only meaningful if the Earth is a bit larger than you previously thought, but you're not quite certain that it cannot be), you need a more elaborate expedition with huge ships and lots of food, perhaps with some plans to train a new generation of sailors. And the practical benefits are potentially decreasing – or they're being moved to the future.

But none of these practical considerations – how easy it is to swim or sail to Trumpia, how practical it is, how big a profit you may expect to make, how many centuries it will take for the population density of the Manhattan or the New World to match that of Spain, and so on – has anything to do with the pure truth value of the proposition "a new continent to be named Trumpia exists" or with the value of its distance from Spain.

Most people – the aforementioned semi-autonomous organisms – just seem totally unable to focus on the actual proposition and evaluate its truth purely impartially. They seem unable to resist the temptation to mix the truth of a well-defined proposition with some totally different aspects of their practical lives. When we talk about the geological theories and other arguments that may direct us towards a more realistic answer to the questions about the existence of Trumpia and its distance from Spain, they just clearly can't be affected by some musings about someone's swimming or the funding he gets or doesn't get for his ships.

Why is it so difficult for so many people to understand this basic separation? To understand the very clear meaning of certain self-evidently well-defined hypotheses – and the value of some self-evidently nontrivial arguments in favor or against various hypotheses? Many people are just dumb vertebrates, that's what Darwin's theory implies. In most cases, they're basically only as smart as needed for the survival. For example, Charles Darwin has demonstrated that women have one extra neuron relatively to a horse for them not to drink a bucket while cleaning stairs. ;-) I hope that friends Kai Smolin and Amythist Ariara will share this politically correct joke with their equally brainwashed multiculturalist classmates in Toronto. Cattle probably wouldn't do much better than Woit and his readers, I sometimes think. This possibly correct observation calms me down whenever I eat a hamburger or a steak.

In the 15th century, you didn't actually have a clear proof that America was 3,000 km away from the Spanish beaches. Now you have it. We may see all things with hindsight and this makes a difference. People couldn't reliably make certain logical steps that we can do today – because they didn't have the hard data or the certainty about them. On the other hand, our current knowledge is more complete and it allows us to say which behavior was surely counterproductive and which behavior was logically valid or promising.

So the people who were saying that "new continents were not even wrong" back in the 15th century were just dinosaurs from the medieval epoch. Whether the new continents were going to be found or not, and whether it was soon or much later, the question about their existence made a complete scientific sense. It's in principle possible to map the whole Earth. So how could a rational person suggest that the very research into those questions was "not even wrong"? He couldn't. Only dimwits could. Only the stupid people could say that the hypothesis about a new continent was "just like God". It's just a damn huge rock in the ocean. It's either there or not. In what sense could it be said to be analogous to God? Only idiots could say it's analogous. Maybe such idiots don't find it embarrassing because they're surrounded by other idiots so it's fine. But it's not fine here and I think it's a moral duty to emphasize that these mammals are intellectually on par with cattle.

Now, the four positive hypotheses – 30 km, 300 km, 3,000 km, 30,000 km – have had not only different "totally practical or commercial consequences" for the colonization of the New World. They also had different implications for the evaluation of the hypotheses and their proponents. Well, the closer Trumpia is to Spain (and the lighter the WIMP is), the easier it is to decide whether the corresponding hypothesis is correct – and to either reward or punish its proponents.

But these impacts on the scientific strategy and careers are still just some "practical consequences" that have nothing to do with the truth value of the options. Geology and the Earth just don't give a damn whether some swimmer drowns or whether some geologist or explorer gets promoted, or whether his sponsors will have to take a risk, or whether someone will be even motivated to cheat. The truth still exists independently of all these societal phenomena. And the person who wants to find a greater fraction of the truth must proceed honestly and logically and take the existing valid evidence into account – while he must protect his mind from invalid and demagogic arguments.

The proponents of the "Trumpia that is 30 km from Spain" will include some bold or optimistic people. Many of them will believe that a new continent is 30 km away because that would "totally change the picture and their life". This possibility, if true, gives them the chance to get rich quick. They swim to the New World, conquer Manhattan, and rent it to the Wall Street. Similarly, experimenters hoping that a WIMP of mass 30 GeV exists may hope to be celebrated as great discoverers – and to get their Nobel and other prizes – very soon.

In the case of high energy physics, some of the tendency for the phenomenologists to propose "new physics around the corner" is driven by the same practical boldness whose origin looks so obvious in the case of the new continent. It was sometimes masked by the "explanations built on naturalness" but many of these people actually wanted to bet on "new physics around the corner" simply because of the practical "get rich quick" mentality. Naturalness is a very strong argument but new particles that are 10 times heavier than the Higgs are fine enough, especially after we learn that the Higgs is probably the lightest one in this "package" of new particles (plus Higgs). So while some people used "naturalness" to hope for new physics around the corner, much of it has always been a "wishful thinking" and a "get rich quick" mentality. I don't say that all phenomenologists were always driven by these sentiments and I can't even tell you which of them were surely driven by it but many of them were.

On the other hand, the top-down theorists are OK with scenarios that are not very accessible (or that are completely inaccessible) to experiments in a foreseeable future (or any future involving humans). They like to think about continents that are more than 3,000 km away – or particles with masses above 3 or 10 TeV or near the GUT scale or Planck scale. They don't really plan to swim to Manhattan and that's one reason why they're immune towards the "get rich quick" bias. Instead, they find certain mathematical rigidity in some ideas which is more exciting for them than the swim to Manhattan. Because many of the theories they're investigating are far from the doable experiments in the near future, they may be accused of being like "theologians" but they're nothing like "theologians" because all the questions still make a perfect scientific sense. The only correct observation is that their critics just don't give a damn about high-brow yet impractical questions – they are fellow mammals who only care how much they eat and what it costs. But their being at most slightly above the intellectual average of eukaryotes doesn't mean that the top-down theorists' science isn't science. If one measures the "proximity to theology" by people's interest in impractical or very long-term questions and projects, then indeed, theoretical physicists – especially the top-down ones – are "close to theology". But there's nothing wrong about it. On the contrary, the existence of these people is what makes the mankind human.

But whether some people sympathized with the bottom-up or top-down approach didn't really matter for the truth because at some point of the history, a new continent that was 30 km away from Spain was really possible in principle. The option was investigated – well, it was probed well before the 15th century – and it was falsified. Because this option, "Trumpia that is 30 km from Spain", was refuted, all the serious people who were thinking about the hypothetical new continents had to take the new evidence into account. In the jargon of the demagogues, they had to "shift the goalposts".

The new continent that is 30 km away was experimentally falsified by some boats at some point. Similarly, a 30 GeV WIMP was falsified at some point in the 20th century, too. The lower bound on the distance to Trumpia – or the lower bound on the WIMP mass – had to be increased because the most accessible option simply got refuted. By the way, the people who hoped to "get rich quick" had to pay with some drop of their prestige because the bet always works in both ways. It's just a bet. You may win big but if your bet is wrong, you also have to lose or pay something. The bet isn't 50-50, it's similarly asymmetric as lottery tickets. You pay a little and you have a small chance to win big. It's fair.

Now, the lower bounds were increased to 300 km for Trumpia or 300 GeV for WIMPs. Great. Is there something immoral or unscientific about this update of the theory or models? Once Trumpia that is 30 km away from Spain is ruled out, does the belief in a Trumpia that is 300 km or 3,000 km away from Spain become a religion? I think that every rational person understands how ludicrous such a statement would be – and indeed, the metaphor is constructed so that the two situations are perfectly isomorphic to each other. There is no New World that is 30 km from Spain. But there can still be a new continent that is 300 km from Spain, right? Some people – especially swimmers – may get discouraged by the absence of a new continent that is 30 km away from Spain. But their discouragement doesn't imply that there's no continent that is 300 km or 3,000 km away! Discouragement is just someone's emotion, it is not a logical valid argument. If someone doesn't want to swim America any longer, it doesn't mean that America doesn't exist.



Similarly, there's no 30 GeV WIMP but there may still be a 300 GeV WIMP. Now, 300 km away from the Spanish beaches were also refuted – not such a long time before 1492, I think, but the detailed history of marine exploration isn't the key of this blog post, of course. The 300 GeV WIMP was roughly being ruled out by the LHC in recent years – a 300 GeV LSP is still marginally viable with some extra assumptions, it's a messy thing and any short proposition about these exclusion limit is bound to be a massive oversimplification.

But when 300 km or 300 GeV get falsified, it still doesn't eliminate the whole WIMP paradigm – or the idea about a new continent, does it? The 3,000 km Trumpia is as viable as it was before the 300 km vicinity of Spain was checked. Similarly, the 3 TeV WIMP is as viable as before. With some adjustments, perhaps adjustments to the original, precisely thermal evolution of the Universe, it's marginally compatible with the original WIMP miracle.

The people-animals seem to have a tremendous psychological problem with "shifting the goalposts" e.g. from 300 km to 3,000 km – from 300 GeV to 3 TeV. Why? It's just a damn strengthened lower bound on some parameter of a new paradigm. "Shifting the goalposts" is a phrase that is meant to describe something morally negative. But if you just use a morally negative phrase in some context, it doesn't mean that something morally negative is actually taking place. Some sub-options have been falsified but others haven't been. You still need to compare the probability of the detailed options that remain viable – and a Trumpia that is 3,000 km away remained viable, just like a 3 TeV WIMP is viable now.

You need to stretch some old-fashioned estimates of the mass a bit, to allow a 3 TeV WIMP, for example. But there's nothing "immoral" or "unscientific" about such a stretching – the same point that the people-animals just don't seem to get for some reasons that make them look like a different species in my eyes. In the history of science, such a stretching and numerical adjustments of otherwise great theories and paradigms are virtually omnipresent.

Hubble originally observed the expansion of the Universe. Hubble's constant is roughly inverse to the age of the Universe and his originally determined age of the Universe was some 3 billion years or so. Great. The paradigm was kept but the Hubble-like observations and their numbers were adjusted and we believe that the age of the Universe is 13.83 billion years today – more than 4 times older than Hubble's original cosmic age.

Atoms were originally assumed to be much larger than we have today – they're smaller but the paradigm was right. Millikan measured the elementary charge and due to some viscosity blunder, his original value of the electron's charge was wrong by a factor of two. Lord Kelvin believed that the Sun had to be something like a coal furnace and the Sun therefore couldn't be much older than millions of years. It's billions of years, Charles Darwin got a better answer while avoiding physics altogether, but Lord Kelvin still exploited a wonderful argument of the type we still use today – he just hadn't known about the very concentrated nuclear energy that changes the numbers dramatically, relatively to coal.

Electron could have had heavier cousins and they were first expected to be closer to the electron. But the muon is 207 times heavier. The top quark (and, a year before the 2012 discovery, the Higgs boson) was originally expected to be lighter, too. The cosmological constant was assumed to be zero because the upper bound already seemed unnaturally small. Nevertheless, the paradigm survived while the value of the cosmological constant was shown to be nonzero but smaller than all natural expectations.

Science is absolutely full of stories in which the qualitative paradigm existed first, it finally won, but the numerical parameters that were shown correct were different than estimated at the beginning (estimated by pure prejudices). It's not shocking that the numbers change – if the original numbers were just guesses designed to show that the qualitative paradigm may work. In most cases, the originally assumed values of the parameters were "more ambitious" or "closer to the everyday life" (or "accessible to swimmers"). In most cases, the actual measurements showed that the new effect is "further away from the easy tests" and therefore "further from the everyday life and practical applications" than originally thought. Well, indeed, I think that in most cases, the hierarchies were also seen to be larger than originally thought, therefore stretching the expectations based on naturalness.

If someone is convinced that it is unethical to "shift the goalposts" in the sense of tightening the lower bounds in the wake of the new experimental data; or if someone believes that it is impossible for a paradigm to be right if some purely guessed parameters have to be increased by a factor of 5, 10, or 50, perhaps twice or thrice, then he is absolutely irrational as well as completely ignorant about the whole history of science because almost nothing would be left from science if it were abandoning all the whole qualitative paradigms as soon as their versions with the originally proposed numbers were ruled out.

This kind of "falsification without falsification" or "falsification by association, pure slurs, insults, and accusations" simply doesn't belong to science and everyone who is doing these things is just a stupid, obnoxious animal.

And that's the memo.

Fusion kid: While a brainwashed Swedish teenage girl gets all the media attention because of her climate hysteria, you need to read TRF to read that a 14-year-old Tennesse boy Jackson Oswalt has achieved fusion of deuterium nuclei in his home-based lab. This comparison says a lot about the current journalists' priorities and values.

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