New form of baloney sold as “multiverse”

Suppose we assume that the universe is an extremely “regular” sort of place, so that everything that happens happens in a “lawlike” way, in accordance with the laws of physics. This assumption has guided physics since Newton’s day. With that assumption in place, apparently “random” events – those that do not occur with the otherwise universal regularity – can seem to present a problem. Why did this rather than that happen, given that both possibilities seemed to be equally “ordained” or “unordained” by law? What “made” this rather than that happen? Why was one possibility realized and the other one not realized when there is nothing to choose between them?

One “solution” to this supposed “problem” is to say that both things actually did happen – that the universe split into two, no less. One universe contains one possibility – what we actually see happening. And the other universe contains the other possibility – what our new twins in the other universe presumably see happening instead.

I have put sneering quotation marks around the word ‘problem’ to indicate that I do not see “random” occurrences as a problem at all. But even if we do see them as a problem, and accept the above “solution”, a new “problem” arises: how is it that we find ourselves in “this” universe? How did it come to pass that I am located on this rather than that “branch” of the ever-expanding “tree of possibilities”? The pathway that can be traced back from my particular “branch” down towards the root of the “tree” takes apparently “random” turns in exactly the same places as the entire universe did before we posited multiple universes to avoid the apparent randomness!

So we are left with a supposed “explanation” that leaves as much unexplained as it began with – and now we also have to countenance an innumerable, unimaginable number of universes into the bargain! William of Ockham – whose “razor” tells us to choose the simplest possible explanation – would not be pleased. The idea is that “entities must not be multiplied beyond necessity” – and by “entities” Ockham wasn’t even thinking of entire universes but the posits of explanatory hypotheses.  Allowing entire universes to work as explanatory posits is to multiply entities beyond sanity.

Apart from being a remarkably bad bit of thinking in itself, the fact that this “multiverse” theory (as it is known) is so widely accepted, or at least taken seriously, exemplifies some other remarkably bad habits of thought. Ordinary people – i.e. non-scientists – do not point at it and ridicule it. Why not? Physicists do not blush when it comes up in conversation. Why not? Both bloody well ought to!

Physics is a remarkably good science. For most of its life, from Newton’s time to the present, its theories have had great explanatory and predictive powers. But something strange happened in the twentieth century. The “lowest level” of physics – quantum theory – turned into a formalism. This formalism has breathtaking predictive powers, and almost all of the marvels of recent technology rely on it. But it has almost no explanatory power, because no one understands it. You don’t have to take my word for that: Richard Feynman, himself one of the most important contributors to quantum theory, said “it is safe to say that no one understands quantum theory”.

The subatomic world is so unlike the macroscopic world, and it is populated by such unfamiliar objects, which interact with each other in such an unusual way, that we don’t know how to interpret the mathematical formalism that so successfully predicts its workings. Honest, reflective physicists admit that. But there is a less honest, less reflective type of physicist too, one who is flattered by public admiration for the predictive powers of physics and for the seemingly miraculous modern technology it makes possible. This type of physicist comes to believe that he is himself a sort of miracle-worker.

This is exacerbated by a sad fact about humans. When we don’t understand something, we tend to fall back on the supernatural and the “spiritual”. If it seems to us that some interaction is taking place but don’t understand how, we tend to start talking about minds and ghostly mind-like kinds of stuff. We can see this in many places in physics, from the yin-and-yang symbol that Niels Bohr chose for his coat of arms to the current usage of the word ‘information’ in physics (to mean something quite different from what we normally mean by the word).

Some physicists are so firmly in the grip of the idea that they are the unique purveyors of “spirituality” that, like their religious forbears, they do not trouble themselves to consult others who have given such matters more thought than they have.

For example, consider the thought I began with, that the universe is an extremely “regular” sort of place, so that everything that happens happens in a “lawlike” way. Why should anyone expect this to be the case? A scientific law is just a special sort of description – a far-reaching generalization (as in “what goes up must come down”). It does not “make” things happen, as Hume was the first to recognize. I used the word ‘ordained’ above, again in sneering quotations-marks, because scientific laws don’t “do stuff”. They’re just bits of human language that purport to describe stuff. The events they purport to describe either do happen in a regular pattern (so that Xs always follow Ys), or else they don’t. If they don’t, our descriptions or understanding are lacking in some way. That is an appropriate moment for modesty, and for scepticism, rather than the ludicrous extravagance of “multiple universes”.

We don’t have any compelling reason to believe that everything that happens in the universe does conform to regular patterns. Practically the only reason we can have to think that way is: we tend to assume the universe is “intelligible”. And I submit that that assumption comes from the vague idea that God designed it to be “orderly”. We don’t get the assumption from the universe being so orderly than we can imagine nothing but orderliness, because we would have the idea even if the universe was less orderly than it really is. (To see this, imagine that atoms of the same isotope differ from each other slightly – we would still assume they were indistinguishable below the level of our ability to discern between them.) The assumption of orderliness may guide science, but it isn’t one of the deliverances of science.

Physicists who have read Hume or at least thought about Hume’s most celebrated ideas will be aware of that. And physicists who haven’t won’t be. And the latter are condemned to rehearse a play of ideas that has already been staged, by philosophers, quite some time ago. (‘Condemned’ is too harsh a word, as they still enjoy the adulation of the general public.)

Physicists who do not bother to reflect on the insights that philosophers have already had make worse physicists than those who do, just as philosophers who do not bother to reflect on the insights of physicists make worse philosophers.

We need each other. We need to criticize each other. Philosophers need to be less timid about physics. Some of it is obviously stupid crap. And physicists need to think more deeply – and more – about possibility, cause, scientific laws, explanation, the place of the mind in the physical world, and so on. Philosophers have much to contribute here. And the general public needs to be more skeptical of extravagant claims made by people they look up to. Everyone wants to call himself a “sceptic”, and hardly anyone even knows what the word ‘gull’ means. But the gull population greatly exceeds that of genuine sceptics.

Does your doctor ignore the base rate?

From Think, by Simon Blackburn

Suppose you decide to check yourself out for some disease. Suppose that this disease is quite rare in the population: only about one in a thousand people suffer from it. But you go to your doctor, who says he has a good test for it. The test is in fact over 99 per cent reliable!

Faced with this, you take the test. Then — horrors! — you test positive. You have tested positive, and the test is better than 99 per cent reliable. How bad is your situation, or in other words, what is the chance you have the disease?

Most people say, it’s terrible: you are virtually certain to have the disease.

But suppose, being a thinker, you ask the doctor a bit more about this 99 per cent reliability. Suppose you get this information:

(1) If you have the disease, the test will say you have it.

(2) The test sometimes, but very rarely, gives ‘false positives’. In only a very few cases — around 1 per cent — does it say that someone has the disease when they do not. These two together make up the better than 99 per cent reliability. You might think that you are still virtually certain to have the disease. But in fact this is entirely wrong. Given the facts, your chance of having the disease is a little less than 10 per cent.

Why? Well, suppose 1,000 people take the test. Given the general incidence of the disease (the ‘base rate’), one of them might be expected to have it. The test will say he has it. It will also say that one per cent of the rest of those tested, i.e. roughly ten people, have it. So eleven people might be expected to test positive, of whom only one will have the disease. It is true the news was bad — you have gone from a 1 in 1,000 chance of disease to a 1 in 11 chance — but it is still far more probable that you are healthy than not. Getting this answer wrong is called the fallacy of ignoring the base rate.

Enough of religion pretending to be science!

Climate science raises some interesting philosophical issues. Just as remarkable as climate science are attitudes to climate science. I would argue that its methodology precludes it from being a science at all. Yet it is touted as a science by people who mistakenly think science is the most trustworthy form of human knowledge. Many such people vilify its detractors as “deniers” who have an unwholesome political agenda. A “denier” is someone who wilfully turns his back on the obvious, presumably because his judgement of obvious facts has been derailed by malice. This sort of vilification involves strong feelings.

But these strong feelings are not the product of epistemological, scientific or political insight. Instead they express an old-fashioned hostility to something like heresy. The orthodoxy that the “heretics” fail to respect is the idea that there is a “way things were meant to be” in nature, which humanity is straying from, to our collective peril (or so the story goes). The non-believer isn’t seen as a modest sceptic who begs to differ, but as a ringleader perverting the proper course of humanity, endangering “the planet”, disrupting the “ecosystem”, a blasphemer whose opinions are an affront to those who do see clearly how things were meant to be.

Whatever it calls itself, this is really a reference to a something like a “divine plan” in nature. Such primitive religious nonsense lurks in the background of most discussion of climate change, and I think it’s about time we brought it out into the open.

Scepticism can enter the debate over climate change in a number of places. We might reasonably doubt whether current change is anything out of the ordinary, as a changing climate seems to have been a routine matter over the course of the Earth’s history. In addition to that, we might also reasonably doubt that current change is primarily caused by human activity rather than, say, fluctuations in solar activity. In addition to that, we might also reasonably doubt whether there is anything effective we humans can do to prevent climate change, rather than just dealing with new problems as they arise. In addition to that, even if we can take some effective steps, we might also reasonably wonder whether our “cure” is worse than the “disease”: putting the world economy into reverse would bring famines which kill people. In addition to that, we might also reasonably doubt whether climate change would be a bad thing at all, especially if it involves a change to greater warmth. By and large, civilizations advance and diseases retreat when the climate warms.

There is evidently plenty of room for doubt in this debate. The last sort of doubt brings me close to my central point. Why do so many of us assume that any sort of change would be change for the worse? – I suspect it is because many of us entertain residual religious assumptions about there being a “way things were meant to be”. We are inclined to see the world as a delicately balanced or finely adjusted “mechanism” rather than what nature blindly settled on – or better, whatever current pattern nature is randomly and aimlessly exhibiting as it passes from one pattern to the next – as evolutionary theory would say instead. Most of us claim to accept evolutionary theory, but we don’t think about its ramifications enough, or about how directly opposed it is to traditional religious ideas about nature having a “design”.

The concept of an “ecosystem” has been a great help or hindrance here, depending on which side you’re on. It sounds like a legitimate scientific idea, a biological “place for everything and everything in its place” like the organs of a single living organism. But really the idea is just the apotheosis of the way things currently happen to be, which is not designed by any sort of mind or agency, and cannot be regarded as having any greater value than any other arrangement – at least not from a larger perspective than that of human aesthetics.

It’s worth taking a few moments to reflect on the differences between the body of an individual living organism, which really is a genuine system, and a habitat or so-called “ecosystem”. The organs of the body of an individual organism are indeed arranged in such a way that they work together, and help to promote the proliferation of the organisms’ genes. Because they serve a purpose to the larger body they belong to, we might think of them as having a “design”. They were shaped and in that sense “designed” by natural selection. But the word ‘design’ here is strictly a metaphor – they were not literally designed. We can speak of their “purpose” as a shorthand way of referring to the contribution they made in the past to the survival and reproduction of their owners’ forbears.

An ecological system is completely different – so different that it hardly deserves to be called a “system” at all. Its pattern is simply whatever happened to result from competition and other random forces. Many such forces are mere coincidences that come into play as the living things that share an environment jockey for position, often against each other, with indifference if not outright cruelty. If some aspects of the environment happen to be useful and therefore serve a “purpose” to us or other living things, that is a sheer accident. The chips fell wherever they happened to fall, and if we re-arrange those chips, there’s no reason to think they will end up in a worse arrangement.

The fervour with which climate science is defended is not really the passion of true lovers of science. Anyone who thinks science gives us more secure or trustworthy beliefs than common sense has a poor grasp of science, which is theoretical and inherently risky. The fervour is really the defensiveness of people whose articles of faith are challenged. I think the main article of faith is that there is a design in nature that we are morally obliged to protect.

In the 1960s, it became fashionable to speak of nature in “romantic” or even mystical terms, as Wordsworth and others had done during the original romantic movement. In many ways that was a good thing: various forms of pollution were recognized as an evil rather than an acceptable by-product of progress. And it is good for people to “respect” nature, both its beauty outside us, and its inescapable and often destructive forces inside us.

But we mustn’t let respect for nature turn into reverence for nature. It is quite appropriate to be inspired, impressed, awed, touched, or appalled by nature. It is not appropriate to treat nature as “the way things are ordained”, an attitude that is becoming increasingly common. The worship of “the natural” has become a sort of religion, all the more insidious for masquerading as science.