Sister blog of Physicists of the Caribbean in which I babble about non-astronomy stuff, because everyone needs a hobby

Wednesday, 3 August 2016

Science is not about certainty, obviously

Many, many good and provocative things in this, via Adam Synergy.

There hasn’t been a major success in theoretical physics in the last few decades after the standard model, somehow.

That should be "breakthrough", not "success". There have been a great many successes, not least of which are the Higgs Boson and gravitational waves. But are they breakthroughs ? Yes and no. Yes because GW's will help us reveal more about the universe than we could otherwise learn, but no because we haven't yet found the breaking point of the standard model. Theories have been validated, they have success - but that's not always the same as making progress.

If Einstein had gone to school to learn what science is, if he was any one of my colleagues today who are looking for a solution of the big problem of physics today, what would he do? He would say, “OK, the empirical content is the strong part of the theory. The idea in classical mechanics that velocity is relative: forget about it. The Maxwell equations: forget about them. The theories themselves have to be changed, OK? What we keep solid is the data, and we modify the theory so that it makes sense coherently, and coherently with the data.”

To an extent. He would be aware that any new theory had to give results at least as good as the old one where applicable, and/or make predictions in new areas. He would seek something that approximated to the old theory under certain conditions. He certainly wouldn't forget about the old idea or its predictions, but he'd be happy to abandon the old conceptual basis of the model.

That’s not at all what Einstein does. Einstein does the contrary. He takes the theories very seriously. He says, “Look, classical mechanics is so successful that when it says that velocity is relative, we should take it seriously, and we should believe it. And the Maxwell equations are so successful that we should believe the Maxwell equations.” He has so much trust in the theory itself, in the qualitative content of the theory—that qualitative content that Kuhn says changes all the time, that we learned not to take too seriously—and he has so much in that that he’s ready to do what? To force coherence between the two theories by challenging something completely different, which is something that’s in our head, which is how we think about time.

Well, I'm not sure about that. Certainly he believes Maxwell's equations, because they demonstrably work. But Maxwell's underlying concept was some very strange notion about vortices (http://www.clerkmaxwellfoundation.org/DysonFreemanArticle.pdf) which I seem to recall no-one took very seriously. So I am not at all convinced there is such a strong difference between the way Einstein thought and the way modern physicists behave.

Every physicist today is immediately ready to say, “OK, all of our past knowledge about the world is wrong. Let’s randomly pick some new idea.”

No, that's the way of the pseudoscientist, not actual scientists. This is the first time I've ever heard anyone accuse mainstream scientists of being too innovative !

But it’s absurd when everybody jumps and says, “OK, Einstein was wrong,” just because a little anomaly indicates this. It never works like that in science.

Yes - but this is what the media hype is all about. It is absolutely not the case in real science. I'm amazed to hear an actual scientist suggest this is what happens, because it doesn't.

Science is not about certainty. Science is about finding the most reliable way of thinking at the present level of knowledge. Science is extremely reliable; it’s not certain. In fact, not only is it not certain, but it’s the lack of certainty that grounds it. Scientific ideas are credible not because they are sure but because they’re the ones that have survived all the possible past critiques, and they’re the most credible because they were put on the table for everybody’s criticism.

The very expression “scientifically proven” is a contradiction in terms. There’s nothing that is scientifically proven.... If we’ve learned that the Earth is not flat, there will be no theory in the future in which the Earth is flat. If we have learned that the Earth is not at the center of the universe, that’s forever. We’re not going to go back on this. If you’ve learned that simultaneity is relative, with Einstein, we’re not going back to absolute simultaneity, like many people think.... I seem to be saying two things that contradict each other.

That's because you are. You cannot say, "we're not going to go back on this" and, "nothing is ever proven with certainty". The two ideas are mutually exclusive. Some things - a few, rare things - are known with what we should approximate to certainty. The Earth isn't flat - the only way that could ever be the case is if the Universe was all a simulation or run by a capricious deity. Those ideas are possible, but they aren't science. You can't do science without assuming an objective, measurable reality. But this level of certainty is a rare thing indeed, and of course that's not what science is largely about.

The question is, Why can't we live happily together and why can’t people pray to their gods and study the universe without this continual clash? This continual clash is a little unavoidable, for the opposite reason from the one often presented. It’s unavoidable not because science pretends to know the answers. It’s the other way around, because scientific thinking is a constant reminder to us that we don’t know the answers. In religious thinking, this is often unacceptable.

Only if you take the stereotype of religious thinking, and actually science does claim to know things, or at least it knows them well enough to rule out some claims. Earth created in six days ? Nope. That didn't happen, end-of. Entire Universe run be a supernatural deity ? Totally unprovable and well beyond the remit of science.

The scientists who say “I don't care about philosophy” —it’s not true that they don’t care about philosophy, because they have a philosophy. They’re using a philosophy of science. They’re applying a methodology. They have a head full of ideas about what philosophy they’re using; they’re just not aware of them and they take them for granted, as if this were obvious and clear, when it’s far from obvious and clear. They’re taking a position without knowing that there are many other possibilities around that might work much better and might be more interesting for them.

On this I completely agree.

https://newrepublic.com/article/118655/theoretical-phyisicist-explains-why-science-not-about-certainty?

2 comments:

  1. In future centuries, the archaeologists of science will find the remains of hapless physicists, perfectly preserved in the La Brea Tar Pits of Metaphysics....

    ReplyDelete
  2. String theory gets lots of press, but what exactly is the idea behind loop theory?

    ReplyDelete

Due to a small but consistent influx of spam, comments will now be checked before publishing. Only egregious spam/illegal/racist crap will be disapproved, everything else will be published.

Whose cloud is it anyway ?

I really don't understand the most militant climate activists who are also opposed to geoengineering . Or rather, I think I understand t...