Posts Tagged ‘ockham's razor’

PARTICLE THEORISTS POISON COSMOLOGY

November 4, 2021

Despite three decades of effort and tens of millions of dollars spent on accelerators and their like, it looks as if Particle Physics is coming to a sad end. No new particles beyond those such as the Higgs Boson proposed 50 years ago, and in particular none of those Supersymmetric particles which theorists had hoped would explain that greatest of all scientific mysteries — Dark Matter. Of course there will now be cries for more money and even larger machines, after all the Large Hadron Collider at CERN in Geneva is a mere 27 kilometres in circumference. But wait! Perhaps there is something far more interesting and fundamental at work: Perhaps Particle theorists have misled themselves, and everybody else , through neglecting a philosophical principle at least a thousand years old called ‘Ockham’s Razor’ (OR), named after a mediaeval monk called Friar Ockham.

At the heart of the Scientific Method is the business of Hypothesis Testing, which is where OR comes in. It states “Always prefer the simplest hypothesis first” and that, I suggest, is where Particle Theorists went so horribly wrong. Their “Standard Model” — as they call it, is fiendishly complex — what with its Quarks, Gluons, ‘Asymptotic Freedom’ and so on and so on. How do we measure complexity in Science? By the number of ‘Free Parameters’ (FPs) needed to describe a theory. One way you can think of them is to say they are arbitrary numbers brought into a theory to force it to fit the experimental data. A ‘good theory’ doesn’t need many FPs because it fits the experimental world naturally(for instance Newton’s very successful Theory of Gravitation has only 2 FP s) The so called Standard Model of Particle Physics needs no less than 18 FP s which has always suggested that it is an ugly and unnatural construct. It should be no surprise then to find now that it actually looks to be wrong.

So why did theorists construct such an ugly model in the first place, mostly back in the 1960’s and 70’s? Probably because they didn’t understand just how fundamental OR is. And there’s some excuse for them — because the Philosophers of Science, the self-appointed arbiters of the Scientific Method, didn’t understand OR themselves. Even Einstein, who relied on it extensively, waffled about some plastic ‘God’.

As I see it Hypothesis Testing works like this. You have some data-points, with error bars of course, and you have your hypothesis which generates a smooth curve which you must try to fit through those points. If there are lot of points the Odds on your hypothetical curve fitting them all by chance must be small. So if it does so fit then the Odds are that the hypothesis is probably right. If it doesn’t fit then you can always complexify your hypothesis ,so twisting your hypothetical curve until it does fit. But you can see that’s not a very convincing way to proceed, because eventually you are always going to force a fit. In that case the Odds in favour of it being actually right vanish. And that, I would suggest is what happened to Particle Theory, starting half a century a century ago.

There’s nothing fundamentally wrong with modifying a theory to fit the facts, after all that’s how science progresses. But you have to be very frugal in doing so. Only introduce a new concept (FP) into your theory if it fits at the very least two more data points than its simpler predecessor. And that’s hard to do, but it won’t degrade the Odds on it being right. But if it only fits one more data point the Odds will generally degrade dramatically. And that’s what Particle Physicists were tempted to do; making names for themselves at the expense of undermining the Odds on their so called ‘Standard Model’ theory. And that’s why almost nobody believes in their theory anymore. It’s as if they’d undermined their currency by printing too many notes. It works for a while — then collapses!

I am not a Particle Physicist, thank God, I am an Astrophysicist. And what worries me is that those same Particle theorists have dragged their own dodgy practices into our subject, with predictably unhealthy consequences. Take “Dark Energy”, an entirely artificial concept dragged into Cosmology by a particle theorist called Ed Turner from the Fermi Lab (and the University of Chicago). Now astronomers are raising hundreds of millions of dollars to chase this fantasy around the cosmos when there’s no justification for doing so, none at all. It was a thoughtless quick-fix extra Free Parameter to fit the apparent acceleration of Cosmic Expansion inferred from Supernova measurements in 1998. Had its introduction explained TWO or more discrepancies between theory and observation we might have welcomed it in. But it didn’t. So it should never have been introduced in the first place. Never!

PS Actually the situation is far worse than I am implying because the bloody particle theorists who have undermined their own subject actually introduced two more unnecessary FPs into Cosmology before Dark Energy: ‘Inflation’ to cure Isotropy and nothing else, and ‘Dark Matter’ to fix the Cosmic chemical abundances. We need to throw them out too.

So where do we go from here? Cosmology should chuck out Dark Energy, Inflation and Dark Matter and start again without them. As for Particle Physics I suspect that they may have to go back 50 years and try to reconstruct a more parsimonious theory of particle interactions than the ‘Standard Model based on quarks and gluons. In his wonderful book ‘Constructing Quarks’ Andrew Pickering (Univ. Chicago Press 1981) suggested that that theory was a social construct anyway, the product of trendy acclamation, rather than sober assessment.

More generally all of us need to understand the process of Hypothesis Testing on which the modern world of ideas is entirely built. Because if that isn’t sound ,God help us all.

For much more on Ockham’s Razor see our post “Fuzzy Thinking and Ockham’s Razor’ under the ‘Thinking’ category here on our blog. For a detailed explanation of Ockham’s Razor and why it works go to the url:

https://mjdisney.org/wp-content/uploads/2021/11/AMSCI4-copy-1.pdf

But if you want to go into the whole business of Common Sense Thinking (CST) , of which Hypothesis Testing is only a part, try my book “Thinking for Ourselves” publ Amazon (2020) which is described in the ‘My Books ‘ Category on this site.

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COMMON SENSE & GOD

June 25, 2021

Common Sense Thinking needs some tool to discriminate between Truth and Falsehood, or more generally between sound hypotheses and unsound ones. ‘Hypothesis Testing’ ,as it is called, lives at the very heart of Science, Philosophy and Common Sense. As we now know it works by examining the various consequences C1 ,C2, …generated by that hypothesis to see whether they can be observed in practice. If they can be observed that improves our Odds O(H) on the hypothesis being true, if they cannot that reduces our Odds on it. But if the hypothesis generates no consequences we cannot test it , and so can say nothing about it one way or the other. That’s “Bayes’ Rule” which goes back at least as far as 1763 and probably much much further.

Take the hypothesis “God exists”. What consequences does it have? Once upon a time it was argued that the design of the natural world was so miraculous, perfect and improbable that it could only have been conceived by an Intelligent Creator. For instance how else to explain the spectacular plumage of the Rainbow Lorikeet ? [Click on the urls below to see their magnificence]

https://macaulaylibrary.org/asset/349487411/embed/800

https://macaulaylibrary.org/asset/199098091/embed/640

This was the very convincing “Argument by Design”, almost impossible to counter at the time. But in 1858 along came Darwin and Wallace who independently came up with the alternative hypothesis of “Evolution by Natural Selection”. As the Bishop of Worcester’s wife said of it: ” Dear me; let us hope it is not true. But if it is true , we must hope it doesn’t become widely known.”

The general point is that Inconsequential Hypotheses are hardly worth considering because there is no way of assessing their veracity, whereas Consequential Hypotheses are open to verification, at least in terms of their probability(Odds). Thus Evolution has subsequently been detected in, for instance, bacteria under stress , while I am not aware of any consequence for the existence of God which could be tested .

That’s not to say one can’t go on believing in a god — it’s just that the most consequential evidence on his/her hypothetical existence has an alternative, and partially verified explanation, even if it cannot be absolutely categorical.

Then there’s another important philosophical principle that can be brought to bear:Ockham’s Razor — “Always prefer the simpler hypothesis, because its more likely to be right’ [see my Post ‘Fuzzy Thinking & Common Sense’] .The problem with the God hypothesis is that there are so many inconsistent versions of it (4,000 known religions including 20 with a world-wide spread, according to Wikipedia).

Clever people have wasted a lot of their lives worrying about Inconsequential hypotheses — for instance the existence of Free Will [see Post. ‘Free Will and Common Sense] , or in the case of Mathematicians whether their subject was invented of discovered. It doesn’t matter. It’s Inconsequential.

GALAXY GALLERY

October 26, 2020

Morgan, the protagonist in the Written in the Stars quartet, and I, have spent our working lives studying Galaxies. This is the first one he saw when he was looking through the 36-inch telescope at Steward Observatory atop Kitt Peak in Arizona, back in 1969.

Spiral Galaxy NGC 7331 in the constellation of Pegasus, at top. Courtesy, Vicent Peris, University of Valencia.

This particular image was taken much later with a huge telescope 3.5 meters in diameter fitted with an ultra-sensitive electronic camera integrating the light for two whole hours. So imagine how little if anything Morgan would see with the naked eye which integrates for all of a tenth of a second, through his much smaller telescope: virtually nothing at all. That’s why he struggled for half an hour to even convince himself that it must be there, and why he felt that studying galaxies could become the lifetime challenge he was looking for. And so it came to be.

NGC 7331 just happened to be the nearest Spiral overhead his telescope at the time. All the spiky stars are stars in our own galaxy the Milky Way, just hundreds of light-years away, while the spiral lies 45 Million light years beyond them, yet is one of the closest such giant spirals to us.It is about a hundred thousand light-years across! The smaller galaxies lower down are even farther off. Morgan was to spend most of his astronomical life studying galaxies whose light had set out towards him when dinosaurs still ruled the Earth, and some so far away that the Sun and Earth didn’t even exist when their light was emitted.

Even now we know little about these beasts; they are full of mysteries. For instance they spin so fast that they ought to fly to bits. So what holds them together; certainly not the stars we can see in them — their gravitational force would be far too weak. Some astronomers mutter about “Dark Matter”, but what is that, and why have we detected no sign of it after 50 years of searching with every ingenious means we can think of? Then we have no idea how galaxies formed, not if the Universe is really expanding, for their infant stages would have been far too fragile to survive the Big Bang. Galaxies remain a challenge for any young person who would like to spend their lives trying to understand what is out there.

Hard as it was to see, it turns out that NGC 7331 is one of the most visible galaxies there are. Over the course of 50 years Morgan and his colleagues were to find much much dimmer specimens using radio waves instead of light. The next montage shows some typical specimens first located with the Parkes Radio Telescope, then imaged in visible colours with the Sloan optical Telescope in New Mexico, both absolutely state of the art instruments. Its worth studying this montage:

Galaxies first found independently of their light signal in the radio, then imaged optically in several colours (Courtesy Julianne Dalcanton, University if Washington, Seattle).

Believe it or not every postage-stamp contains a galaxy, some so dim one can barely spot them. This illustrates the “Visibility of Galaxies” problem which Morgan discovered in that caravan on the Teifi estuary back in 1975 [See my book Against The Fall of Night]. The problem is that, dark as it appears, the night sky is not absolutely dark so that any galaxy dimmer than our sky would be invisible. And why not? Could most of the structure of the Universe be hidden from sight? Morgan, Cotteridge, Cockle and other astronomers spent their careers wrangling over that question. There’s a great deal to think about here.

Broadly speaking there are two types of giant galaxy, Spirals as above, and Ellipticals. As we can see next, Ellipticals look like giant swarms of bees ( actually very old stars).

The Coma Cluster of Galaxies centred on the supergiant Elliptical NGC 4889 taken with the Hubble Space Telescope, courtesy ESA/NASA.

Ellipticals are just as mysterious as Spirals but in somewhat different ways. For instance NGC 4889 seen here fades imperceptibly into the sky; so where does it end and therefore how big and how massive is it? And why are Giant Ellipticals only found in Clusters? And where have the cold gas and the young blue stars gone that light up Spirals? And why do some of them, like this one, have colossal Black Holes in their cores? And how do these giant Clusters hold together when the gravitational forces required are hundreds of times too weak , if only visible material is responsible. Once again we run into speculations about “Dark Matter” which sound a bit like The Emperor’s New Clothes to me. In other words we are mired in mysteries which challenge anyone with Curiosity. By the way, this colossus is about 300 Million light years away, its light having set out towards us even before Dinosaurs evolved and 50 million years before the great Permian-Triassic extinction, which wiped out 90 percent of the the species on Earth. Yet in astronomical terms it’s almost next door, only seven times as far away as our Spiral friend NGC 7331.

We said most galaxies dwell in Clusters containing anything between a few and tens of thousands. Here is a very large Cluster Abell 1689, 2 Billion, not Million, light years away:

Galaxy Cluster Abell 1689 imaged with the Hubble Space Telescope (Courtesy ESA/NASA)

The further away we search , the further back in time, the greater cosmic mysteries become. For instance what you can actually see here is about one per cent of the Mass actually present. We know that because the galaxies in the cluster are whizzing about so fast that the cluster would have dispersed unless there are overwhelming amounts of “Dark Matter” holding it together [Or else there’s something even more mysterious going on.] This dramatic tendency of galaxies to cluster made it very difficult indeed for Tom Morgan and his friends to find “Hidden Galaxies” because the hidden ones would tend to get lost amid a crowd of ‘Visibles’, requiring great precision to get at the truth.

This, believe it or not, is the identical galaxy NGC 7331 to the one at the top of this post, though the image is flipped left to right..I have put it in for several reasons. First it is in colour because it was made up from several images taken through different colour filters with camera WFC- 3 ( Morgan & co.) on Hubble . This colour information paints a very different picture of the galaxy, which is evidently choked in smoke, so that much of it is hidden. Using the old photographic plates little of this was evident and astronomers were convinced galaxies were transparent. Morgan was practically the first astronomer to realise they were not, largely because he had early access to one of the first electronic cameras. Then there is the atmosphere which blocks off all the ultraviolet, and most of the infra-red radiation included in this picture taken from Space. The general point is that our understanding of the universe is very much constrained by the instruments we have to study it. Space astronomy has widened our spectrum by more than a billion and it may take generations to understand the implications. It’s all too easy to rush to judgement, and to see only what we want to see. Copyright ESA/NASA

When we professional astronomers talk to the public we tend, for sociological reasons, to emphasise what we do know, as against what we do not. Now that I’m retired I can admit that most of the time, at least in extragalactic astronomy, we have little idea of what is really going on. Yes there are fools only too ready to rush in with half-baked explanations such as “Dark Matter” or “Dark Energy”, but I doubt that many will stand the test of time because they ignore Ockham’s Razor, a very profound and vital principle of Common Sense [See my book Thinking For Ourselves or a post on this site entitled Fuzzy Thinking and Ockham’s Razor]. In the mean time they not only rob us of mystery and wonder but they can hold up the search for deeper truths. For instance the invention of fictional “Land Bridges” held back the discovery of Continental Drift by a century.

I hope this post encourages readers, especially the young at heart, to retain their sense of mystery because, as Einstein put it : ” The most beautiful thing we can experience is the mysterious. It is the source of all true art and science”.

You can look up hundreds of more wondrous images of galaxies by going either to stsci.edu, NASA’s Space Telescope institute, or eso.org the European Southern Observatory which runs the world’s largest optical telescope (The ‘VLT’) in the Chilean Andes. But beware of beautiful coloured images which look like pizza advertisements; real galaxies don’t look anything like that, they’re far more subtle and infinitely more difficult to decode.