Friday, May 30, 2008

Letter: Multiverses are nonsense but so is much contemporary physics

Uhlrich Mohrhoff, editor of Anti-Matters, who reviewed The Spiritual Brain, writes regarding multiverses:

I don't think it's a good idea to attack the multiverse idea. Of course I agree with you that the idea is pure nonsense, whether it refers (i) to the many-worlds interpretation (whose adherents are too stupid to distinguish possibility from actuality), (ii) to the attempt to ward off cosmological design implications, or (iii) to the "landscape" of string theory (which is neither a theory nor even wrong).

The reason why I don't think it's a good idea is that it seems to suggest that everything else is fine with physics. Nothing could be further from the truth. A wholesale attack on the very foundations of contemporary physics is in order.

I like to quote the philosopher of science Dennis Dieks (who is also editor of the prestigious journal Studies in History and Foundations of Modern Physics):

Most physicists have no clear conception of the interpretation of their most basic theory, quantum mechanics. They are largely unaware of the exact nature of the problems in giving a detailed and consistent account of the physical meaning of the theory; and if they are aware, they often don’t care very much. Only very small numbers of researchers have given serious thought to the interpretational problems of quantum mechanics, and have expressed more or less detailed points of view. As can perhaps be expected from the statistics of small numbers, the diversity of opinion is large. Very different ideas have been put forward, none of them supported by great numbers of physicists...

The difficulty of developing a convincing interpretation of quantum mechanics can easily be understood. First, the rigorous results which have been achieved preponderantly have a negative character: they are “no-go theorems”. No-go theorems show the impossibility of certain interpretations, but do not themselves provide a new interpretation. For example, Bell’s theorem demonstrates that a “local” theory in which physical objects possess well-defined properties is not possible. More generally, the outcome of foundational work in the last couple of decades has been that interpretations which try to accommodate classical intuitions are impossible, on the grounds that theories that incorporate such intuitions necessarily lead to empirical predictions which are at variance with the quantum mechanical predictions. However, this is a negative result that only provides us with a starting-point for what really has to be done: something conceptually new has to be found, different from what we are familiar with. It is’ clear that this constructive task is a particularly difficult one, in which huge barriers (partly of a psychological nature) have to be overcome...

The physics community thus does not possess a definite notion of what to do with the problems in the interpretation of quantum mechanics, and even is in the unclear about the exact nature of these problems. It operates with a “common sense” interpretation which basically is wrong (and of which one knows that it is wrong)...

Both the empirical success of the theory and the difficulty of beating sense into it have found expression in Michio Kaku's statement that "of all the theories proposed in this [the 20th] century, the silliest is quantum theory.... The only thing quantum theory has going for it is that it is unquestionably correct."

Paradoxes and bewilderment only occur if one wonders about how the calculated and predicted experimental outcomes can be realized by natural processes...

The fact that interpretational problems do not receive much serious professional attention does not appear to be a coincidence. It seems related to the very nature of empirical science, in which empirical success is the ultimate goal and interpretation has at least “officially” the status of handmaiden...

The paradox is that unofficially… physicists have quite outspoken opinions about the general ideas of most interpretations.

For a longer excerpt see this blog post. The complete article has appeared in AntiMatters.

The Nobel winning physicist Frank Wilczek illustrates this schizophrenia by writing, in one and the same article, that quantum fields are the "ur-stuff" and that "we can only require — and generally we only obtain — sensible, finite answers when we ask questions that have direct, operational meaning."

The first thing one needs to know about the fundamental theoretical framework of contemporary physics is that it is a computational tool — a bunch of algorithms that allow us to calculate the probabilities of the possible outcomes of measurements on the basis of actual measurement outcomes. From this irreducible core of the theory two different lines of inquiry proceed — a fruitful one and a red herring. The former analyzes the quantum-mechanical probability assignments — the theory's only testable aspect — in different experimental situations. This is what causes the consternation, for while the implications of these assignments make perfect sense in a spiritual context, they make indeed no sense within a materialistic framework of thought. And as you well know, the name of the game of science is to "save the materialistic appearances."

The second line of inquiry — the red herring — is a desperate attempt to do just this, save the materialistic appearances. There is general agreement among physicists that the Standard Model and General Relativity are effective theories, i.e., they give the right predictions at empirically accessible scales, but they are not the real McCoy, for that would have to be correct at all scales of length. What they don't seem to realize is that their search for the real McCoy is doomed to failure, for if we follow the fruitful line of inquiry, we find that the world is not differentiated "all the way down": if we conceptually partition the world into smaller and smaller regions, there comes a point beyond which the distinctions we make between regions do not correspond to anything in the actual world. They exist solely in our heads. There can be no theory that is correct at all scales of length.

It is intriguing that this point is virtually incomprehensible to most theoretical physicists, who only seem to understand mathematical formulas, while it is readily grasped by someone like the singer/songwriter Stephin Merrit , who in an interview with Pitchfork said:

I just read online a few weeks ago, the Pondicherry Interpretation. It's the physics...attitude of Ulrich Mohrhoff, who happens to teach in Pondicherry India. The Pondicherry Interpretation is startlingly original to me. So I said to myself, "my god, there's a new way of thinking about the world!" The basic idea is that the time-space continuum only goes down so small. And beyond that, measuring is essentially meaningless.

What is alarming is that the Standard Model and General Relativity can be deduced from utterly weak assumptions. Alarming, that is, to materialist scientists, who fancy themselves to be omniscient "in principle" — to know (or be in a position to know) the furniture of the universe and the laws by which that is governed. Quantum mechanics presupposes measurements, and I have shown (at any rate, made it eminently plausible) that the existence of measurements presupposes the validity of the Standard Model and General Relativity.

This means that all well-established theories are essentially tautological — except for one thing: their validity is guaranteed provided that things that have spatial extent are composed of things that lack spatial extent. This is the sole nontrivial input and the only real mystery: why are "ordinary things" — things that "occupy space" — made of things that don't (such as quarks and leptons)?

Here too there is an answer. I won't go into it except to say that it is based on spiritual knowledge or experience, and that it cannot possibly be arrived at by the limited methods of science.

Interesting. As an artsie, I can easily understand the concept of pushing measurements down below a level at which they would be meaningful.

For example, the word "inbox" can be subdivided into "in" + "box" but if you try to subdivide it into five letters i-n-b-o-x, you have a smaller division that doesn't mean much. (Yes, of course, we could go into the etymology, as in "where does the word 'box' come from", but then we are looking for antecedent words, not necessarily the exact words themselves.) And, if you tried dividing the letters themselves, well ... that's the stuff of jigsaw puzzles.