Having found a forum where I can address John Horgan directly, I would like to reply to his Edge talk and the previous "Reality Club" discussion, though this will partly involve retracing some ground covered in my previous articles in the Australian media:

• Article in The Australian, 4 September, 1996; when John's book first appeared.
• Piece recorded for ABC Radio's Ockham's Razor show, April, 1998 in response to John's appearance on their Science Show, (14 March 1998).

Definitive tests in observational cosmology are not going to be any overnight wonder. Because we have no experimental control over conditions in the very early universe or at the centres of quasars, interpreting the data and making exhaustive tests that will satisfy everybody is going to take a long time, certainly tens, maybe hundreds, of years. Many different independent tests will be need to be made before things are truly decided. As an example, recently there has been a test of Gaussianity in the spectrum of primordial perturbations in the cosmic microwave background (see http://xxx.lanl.gov/abs/astro-ph/9803256) - the present negative result could be considered a falsification of the inflationary universe scenario; something which John claimed was untestable in his book. (The jury is still out on questions relating to matter densities; all we know for certain is that the density of ordinary clumped cold matter is much less than critical.)

These tests will have to be repeated and many other independent tests will need to be made before everyone is convinced one way or another on inflation; the reason being that inflation is not a closed final theory but is as yet a general speculative framework of different models with the common feature of an early period of exponential cosmological expansion driven by at least one scalar field. Thus some things can still be tweaked. We need lots and lots of data to nail down what can and cannot be tweaked, and to see whether the essential ideas of inflation can survive any tweaking. The same goes for any other theories of cosmology, and, once we get access to early-times data, theories of high-energy particle physics and quantum gravity.

John describes how great a theory general relativity is phenomenologically, but he never mentions that the reason physicists want to unify it with quantum mechanics is not because we are primarily seekers of beautiful mathematical truths, but because we know for a fact by the singularity theorems of Hawking and Penrose that under physically reasonable conditions general relativity breaks down. It is not complete! As long as something so fundamental as gravity is incomplete the possibility for a major revolution does exist; and the fact that no obvious attempt at quantum gravity has worked only makes it more likely that the "final" version may be a revolutionary one.

The interesting time will come when gravitational wave observatories come on line giving us a view (or rather `sounds'!) of the universe that we have never had before. To add to what Oliver Morton has already touched on, I would mention that space-based detectors in particular will give us access to lower frequency gravitational waves than ground based observatories (limited by seismic noise etc) and this will eventually provide us with substantial hard data about times before the surface of last-scattering (the surface of the microwave background) at very early times when the universe was opaque to electromagnetic radiation. This will be the time when all those speculative "ironic" theories are nailed down. The first space-based detector (LISA) is only due to be launched in 20 years time, and more than one space-based detector will be needed to distinguish the cosmological background from the stochastic background of galactic sources such as white dwarfs. Thus we might have to wait 30 or 40 years for such data, but the time will come.

I should also mention in passing that questions which John might think are of the "filling-in kind" might not be. This is the one warning to take from what happened 100 years ago. The problem of the precession of the perihelion of Mercury was certainly regarded as a "filling-in" problem back then. One just needed to find the planet Vulcan. But this extremely small effect turned out to be a revolutionary problem, not a minor one at all. The solution, which involved weird ideas such as curved space, defied what was known as "common sense" in Einstein's day. I can easily picture John transported back in time 70 years ago, railing against general relativity as many others did then because it defied "common sense". The point is that as long as anything is unknown it is extremely foolish to pretend any certainty in guessing at the answers. As long as things are unknown and mysterious we will keep doing science.

John's use of the term "ironic science" belies the fact that despite all those books he has read on the philosophy and methodology of science, despite all his interviews, he still does not ostensibly display any understanding of how science works. Science does involve forming testable hypotheses, but one cannot form a testable hypothesis unless one has a consistent logical framework within which to pose a hypothesis. You cannot write down a sentence before you learn language. In physics, the language of which is mathematics, this means constructing a self-consistent mathematical framework. Einstein could not have arrived at general relativity if he had not known about Riemannian geometry: 19th century "ironic science". The conventional frameworks for quantum gravity are not mathematically self-consistent. Someone needs to construct such a framework before physicists can pose any testable hypotheses.

Superstring theory is an attempt at such a framework, and it is still far from complete or well-understood, although it is compelling because it succeeds mathematically in places where physically successful theories such as general relativity fall down. In his book, John described Ed Witten as a mathematician as if it were a dirty word, in much the same way that some arrogant physicists refer to their colleagues who write popular books as mere journalists. Of course Witten is a mathematician, or a mathematical physicist if you prefer, and proudly so. The contribution he is trying to make to quantum gravity should be compared to the contribution Riemann made to general relativity, only Witten at least has an application in the back of his mind when trying out the various things he does. The difference between Riemann and Witten is the difference between mathematics and mathematical physics. Of course pure mathematicians do love Witten's work nonetheless, because it gives them many new and interesting areas of mathematics which they can seek to make rigorous, and that is why they gave Witten the Field's medal. Rigor by itself can mean rigor mortis.

If superstrings come to something they will of course have to give us testable hypotheses. As yet we have suggestions of such tests, but because string theory is not completely understood yet the tests are not completely understood either. Even if string theory itself comes to nothing, it would still be fair to say it will nonetheless give us deep insights into how we might go about constructing whatever theory of quantum gravity we will end up with. I agree with John that hard data is needed, and that is why I think we may have to wait at least 30 years before we will have the answer. But that is no reason to rubbish the attempts of the pioneers who are trying to sort out a consistent mathematical framework in which to pose the questions.

As Lee Smolin says, John's book is very much a `here and now' thing. When people accuse John of having no imagination, it is because he seems to lack any long-term perspective on science. Many things which he writes of as "ironic science" are "ironic" merely because they are new and people still haven't worked out ways to collect meaningful data and to make falsifiable hypotheses. Physics has had the benefit of hundreds of years in which to mature. I will agree with John that many social sciences presently do look like psychobabble; but Aristotle's version of physics was psychobabble compared to what we have had since Galileo and Newton. I do not think that Aristotle's contribution was worthless; it got people thinking about the questions to ask, and eventually they did think about the right questions. Even if the people trying to make mathematical models of economics and societies today are wide of the mark, it still gets people thinking about the questions involved. Sciences mature over hundreds, maybe thousands of years. A number of sciences are still in their infancy, whatever obvious successes they have had to date. While it is conceivable that one day we could find that all the important questions that we could think of had been answered, it is grossly premature to be thinking in such terms now.

Imagining possible futures does not mean abandoning physical laws we already have. I imagine that new fundamental physics could fundamentally change our technology, and allow us to explore the nearer parts of the galaxy; but that is more likely to be due to better means of propulsion, not because we will invent Star Trek warp drives to beat the speed of light. It is possible that we will make contact with extra-terrestrial civilizations, but that is more likely to be via transmissions and robot probes due to the limits set by the harsh environments of space, even if we can get near to the speed of light some day by means as yet unknown. The important point is that however long it takes and however slow communication with extra-terrestrial civilizations would be, the possibility of such communication would be one of the biggest revolutions ever for human culture and science. John admits as much; where he lacks imagination is in not being able to stand back and appreciate that over timescales of thousands of years these things could well be possible, even within the limits set by laws of physics `verified' to date.

John's problem is that he is a journalist living in a go-go rush-rush here-now mode of existence where he encounters people who are happy to hype up their results. He wants to interview all the famous scientists, and of course a number of them are pretentious primadonnas. Naturally, we all laugh at his more cunning put-downs; but the fact that scientists have human foibles does not validate John's message. If John needs a taste of his own medicine, he should consider just how pretentious it is to draw the sweeping generalizations he does from a fleeting Zeitgeist firmly rooted in one decade at the end of the twentieth century.

I am actually very surprised that John thinks that the prevailing culture is a "gee-whiz, can-do" one; on the contrary, I think that there is a prevailing mood of pessimism. Because of economic and social constraints the period of very recent rapid scientific expansion is slowing down. Many of those interviewed in his book echoed this pessimism. This has nothing to do with the underlying science, as John mistakenly seems to think. If any of his interviewees fooled him into thinking that way it is more probably due to the fact that by virtue of being famous some senior scientists are occasionally has-beens who, having done their major work, are past their prime and can't think of anything new. (In the first few chapters so many people were dying not long after their interviews with John that I started to keep a tally, but fortunately it didn't pan out.)

The real cause of current pessimism is our present unique point in history. The world's population has grown at a fantastic pace in recent times, more people have been doing science than ever before, but at the same time the world is beginning to reach its maximum carrying capacity in terms of resources and everyone is future-shocked and disoriented by the effect of rapid technological changes on our culture. Governments are not going to pay for any science without limit. The rate of change will slow. But science itself will not be at an end as long as basic scientific questions are unanswered.

If John is fooled by "gee-whiz, can-do" talk it is because he does not sit down enough to analyse the motives of the people he interviews, even if he does sometimes expose them in his vignettes. Of course hard-nosed particle phenomenologists are happy to rubbish speculative models like superstrings, especially if they don't understand the mathematics. Of course some cosmologists and particle theorists are happy to let journalists get away with grossly hyped-up descriptions of speculative models about the beginning of the universe, or so-called "theories of everything" - they probably think it will help the sale of some popular book or other. Equally, I know that the imperative of selling his own book will be a big potential barrier to John ever admitting (to himself even?) that he is wrong.

I am as much against the "fawning" in the popular press as John is; perhaps more so when it's my friends and colleagues who are involved. Having worked in Stephen Hawking's group for four years, I know that the tendency of journalists to treat him like the Oracle of Delphi is too powerful a temptation for him to resist. Yes, a lot of Stephen's ideas are deeply speculative, but there are times when you have to speculate to make any real progress in science. There is always a difficulty in trying to convey to a popular audience what is speculative and what is not, because what is speculative is still exciting. In my own dealings with journalists, when I have been critical of the over-hyping in pieces they write - perhaps I am more critical than the typical interviewee - I have tended (not intentionally) to cause offence. (Unlike scientists journalists often lack the thick skin acquired from the system of critical peer review of one's articles. I hope by now your skin is thicker, John.) I think that all this over-hype, which is greatly encouraged by our present mass-media sound-bite culture, does dreadful damage because it does lead thinking lay-people like John (and even hard-nosed "empirical" physicists like Philip Anderson) to pour rubbish on the whole process of speculation, which as I have outlined above is nonetheless a very vital and valid part of science.

Finally, I am sure that John does not have a hidden anti-science agenda, but the reason I get extremely upset by what he says is, not only is it wrong, but the sorts of ideas John espouses are used as a convenient excuse by those who do have an anti-science agenda in a climate of diminishing resources. This is what I described in the second half of my Ockham's Razor article. The situation for physics in Australia, in particular, is probably worse that elsewhere, because historically physics here has been about half the size it is in other OECD countries (relative to population) whereas biology has been double the average size. When you start from a small base wholesale destruction can take a long time to correct. When you see the physics departments of the University of Queensland and University of Tasmania respectively lose one third and one half of their staff in the space of a couple of years you have to cry. And these are respectable older universities by Australian standards. In "lesser" rural universities physics departments have disappeared entirely, often merging with engineering departments where the culture does not involve asking fundamental questions about science, but something completely different.

Perhaps administrators in the United States are wiser, but as Donald Horne wrote famously 30 years ago "Australia is a lucky country run mainly by second-rate people who share its luck. It lives on other people's ideas, and, although its ordinary people are adaptable, most of its leaders (in all fields) so lack curiosity about the events that surround them that they are often taken by surprise." With this quality of person still in power and now overseeing cuts to Australian universities the myth that "science is finished" makes the cutting all that easier. It is the last thing we need to hear.

Thanks for your message, most of which I agree with. However, I think that John has taken enough criticism and that it is probably as important for those of us who aspire to be doing fundamental physics to be somewhat more self-critical than we are usually, given things like the long period before some of our theories could be tested. In particular I believe that those of us working in cosmology, quantum gravity, string theory, etc. should try always to invent ways to falsify our theories, at least in principle. We should also be always on the lookout for theoretical results that kill our theories, and we should be very honest with our colleagues about when a particular theoretical direction has failed or reached a difficult point. I don't think we always have done these things, which leaves us vulnerable to criticisms of the kind John mentions. In particular, I don't think that the Euclidean quantum cosmology, or no boundary proposal work was ever very disciplined in these senses, one never got a sense of what results might be considered to kill this approach. This was especially problematic given that most calculations were done with oversimplified finite dimensional models rather than with real quantum field theories.

This was why, when we began the loop approach with Carlo Rovelli, we worked hard to find genuine physical predictions, which could easily, were the experiments done, falsify the theory. We found them, in the definite predictions of the spectra of the area and volume operators. We were then also honest about when the hypothesis that the dynamics of general relativity lead to a good quantum theory failed, which was when it was found that the dynamics given by the quantization of general relativity has no good continuum limit, in spite of the fact that it is a finite quantum field theory which is perfectly sensible in all other aspects. This has allowed us to go on and extend the theory, using the results of string theory on the perturbative side to help us construct a non-perturbative theory that may have a good classical limit. Whether we can keep the predictions of the kinematical side of the theory, with its definite predictions, while modifying the dynamics so as to lead to a theory with a good continuum limit, is what much of our current work is directed towards. I believe personally the best hope for success is in trying to construct a theory whose perturbative limit is a string theory. But if no theory can be developed based on the kinematical structure we discovered for diffeomorphism invariant quantum field theories that has a good classical limit, then the whole program will be wrong.

If I may say it also, the point of the cosmological natural selection proposal was that it, and other theories of its kind, are strongly falsifiable. Many versions of the theory were immediately falsifiable and the one I presented in my book would be killed by the discovery of a two solar mass neutron star. Some versions of inflation are also falsifiable, and will be well tested in the observations of the MAP and PLANCK satellites. I agree with Paul Steinhard that standard inflation should be considered killed if Omega overall is not one, and that other inflationary models are not worth much study unless they also naturally lead to robust predictions.

There are other examples that could be given, two are the public announcements last summer by Andy Albrecht that the cosmic string theories disagree with experiment and the papers of Dowker and Kent showing that the consistent histories approaches to quantum cosmology run into serious problems and do not show why the universe is classical. String theory is also rapidly developing as people attempt to overcome its obvious weaknesses such as the apparent lack of a unique vacuum, problems with supersymmetry breaking and the absense of a genuine background independent formulation, all of which probably must be overcome if the theory is to be predictive now. (Although it must be stressed that it is easily falsifiable by Planck scale experiments, so that it is wrong to say that string theory makes no robust predictions.)

The conclusion I draw from this is that it is perfectly possible to be doing fundamental physics and cosmology now, in a way that leads to one's theories being highly vulnerable to either observational falsification or abandonment becuase of failures on the theoretical side. We have no need to take refuge in what may be tested in 30 years time. In my view, we are long passed the stage where quantum gravity and cosmology can go on as kind of games, without being subject to the rigors of real science. This requires a kind of flexibility and willingness to abandon hypotheses and research programs when they are shown wanting. If more people in these areas were behaving like this, I think we would be far less vulnerable to criticisms from John Horgan and people like him than we have been.

Thanks,

Lee

PS Sorry if this sounds a bit harsh, but I do think that it is true that a certain number of people have worked in quantum gravity because they enjoyed the fact that they could speculate without fear of their ideas being subject to test, and this has hurt the progress of the field by making it harder for ideas that are testible to emerge.

Thanks for your comments. Basically, I wholeheartedly agree; I think we should all be self-critical. I don't think that people should be excused from trying to make falsifiable hypotheses in quantum gravity just because it is still decades before we can see past the surface of last scattering. My point was simply that we are eventually going to see past the last-scattering surface, and when it happens it will be one of those rare defining one-off moments in the history of science that John spoke about always in the past tense. Literally, a whole new universe will be opened up to us.

I share your reservations about the no-boundary program etc, which is why I chose to work on black holes rather than quantum cosmology as a student. I do admire your efforts to make falsifiable tests in quantum gravity; there should be more of it!

I'm sure that John has had enough criticism. I wouldn't have intervened at all if it had not been for John recently popping up on our national radio, just at a time when huge cuts are being made to physics in Australia and some administrators doing the cutting are on record as saying things which could be paraphrased as `physics is dead; it's time to study waste treatment'. Although John says he is not anti-science, in practice his views have a strong resonance with the anti-science lobby, and for some of us that is a real rather than a rhetorical issue. John bears a certain moral responsibility for continuing to push his views even though most of us would consider it a non-issue intellectually speaking.

Equally I agree that we practioners in the field have a moral responsibility to be honest about the scope of our results. It's just so difficult when the popular press always wants hype.

Let me say "Amen" to David Wiltshire. I said these things about cosmology in a much more condensed form in my review of Horgan in the THES a year ago but I am glad to see them modernised and expanded upon. On "filling in", the simple, boring subject of strongly interacting electrons--as in High Tc superconductivity--is provoking a typical Kuhnian crisis by stubbornly refusing to fit any standard mold or even several nonstandard ones in spite of at least 2 decades of hard work by a lot of bright people (and even more not-so bright ones!). And I absolutely do not accept his "mysterian" view of the mind and consciousness. He is just afraid we might find something. I agree that too much attention has been paid to JH but there are several reasons for continuing the discussion, of which Wiltshire has given us an emotionally phrased example--another is just to provoke us into answers about why we do go on doing science.

pwa

I'm flattered that you have expended so much energy in trying to poke holes in my end-of-science argument. I haven't responded until now for two reasons. One is that I'm trying to stay focused on my new book, Why Freud Isn't Dead. As I think I said in one of my Edge postings, the new book address what I think is the most legitmate objection to The End of Science, that mind-related science could have a long and glorious future. I'm trying to make an August deadline for a first draft.

The second reason is that I'm slightly burned out on arguing about The End of Science, and it takes a lot to goad me into responding. Your postings, while impassioned and articulate, don't really add anything to what was said by Lee Smolin, Oliver Morton and so on. My responses to them apply to you as well.

I'm moved to write you this note, however, by your kind reference to the "self-honesty" of my book. May I ask you to be more honest with yourself in evaluating your own arguments against me? Blaming me for the decline in prestige and funding of physics in Australia or anywhere else is just silly, an egregious example of blaming the messenger.

By the way, did you know that Phil Anderson--who expressed solidarity with your posting--testified against the Superconducting Supercollider in the early 1990's? As much as Phil will deny it, his view of particle physics is closer to mine than to yours.

If you were more self-honest, you would have to admit that your view that that observations will one day validate quantum cosmology and inflation and superstrings is a fringe position in physics. You are not making a rational argument but a declaration of faith.

I once had faith in the hyperspace future that sustains you and Lee Smolin and Ed Witten and Michio Kaku and others. I just can't believe in it any more, any more than I can believe in a benign, just God. Science, real science, took my faith away.

Faith in scientific progress is admirable and noble; without it, science would not exist. But when such faith loses touch with reality, it violates the scientific spirit. That's where I think you are now, David. Honestly.

John

Thanks for surprising me with your response, over which I heartily laughed. Your ability to set up straw men shows that your talents are obviously wasted in your present vocation. You should try politics.

I have never professed to a faith that "observations will one day validate quantum cosmology and inflation and superstrings". I only know that the energy regime to which these theories purport to apply (and where already 'validated' physics is useless) will be definitively tested, given the technology currently being developed. In fact, as I stated, empirical data which (if it holds up) will falsify inflation, has already been collected and is presently being considered for publication in Ap. J. Lett. I guess one can repeat that until one is blue in the face but you won't acknowledge it.

I have no emotional attachment to any particular variant of quantum cosmology, inflation or superstrings, and the more theories that are falsified the better as far as I'm concerned; it narrows down the search. The more cherished the beliefs are that are overturned, the more exciting the adventure. The only faith I profess to is a faith in the power of experiment and empirical observation. If this central tenet of the scientific method is to be viewed as a "fringe position" it shows a bizarre prejudgement on your part.

Your problem is that the sample of people you choose to interview self-selects for those who have an emotional investment in some particular (sometimes speculative) theory. It's a great thing that you see through the stuff these people want you to believe. A lack of faith in other scientists is in fact the first quality needed to being a good scientist. Unfortunately, not being trained as a scientist you have no criteria on which to independently judge how much of the stories that people are feeding you is motivated by personal or other agendas, and how much just could be right.

Whatever "sins" Phil Anderson has committed for whatever political agenda he has in the funding bun-fight, I still value his irascible comments - people in quantum gravity need barbs from people like Phil to keep us honest. Privately, I would often agree with Phil; I am only defending the worth of the process of speculation, not the ultimate truth of any particular speculations made to date. I know the only good speculations will eventually be subject to test.

By punishing the whole of science for the self-serving misdemeanours of a few of the eminent scientists you interview, you do more harm to the ordinary Joe Blow scientists who are not burdened with the baggage of some particular line that they need to publicise for the sake of their own prestige. We younger `ordinary' scientists often don't have the secure and stable positions that our older more illustrious colleagues do; we're the ones in the firing line. This, as previously stated, is my only personal motive for having the energy to engage in this discussion, futile though it is.

I have never placed the blame for the plight of Australian physics on your shoulders. As spelled out in the Ockham's Razor piece, that is a result of the feudal warlord structure of our university politics which makes disciplines reliant on service teaching (pure sciences) vulnerable when a government cuts overall funding. Because your message is false it obviously cannot be the source of the problem. However, your message does sway pople who don't know better, and who have an interest in avoiding the real issues. We usually count on science journalists as friends, not enemies, and people like you make our fight all the harder.

The use of the prestige of those you have interviewed as a promotional device for a thesis that very few of them would agree to makes your message all the more morally repugnant. But yes, I admit, many of my illustrious colleagues have also employed dubious promotional tactics. You have just seen how easily it can be done, and have had a go yourself. The very controversy you stir is probably also a marketing device.

In contrast to the content of your book I detect little self-honesty in your latest pronouncements. The only thing that came close were your parting remarks to Robyn Williams on the "Science Show" that you would advise a young person interested in science to read your book, get really angry, and endeavour to prove you wrong. The only problem is that in today's anti-science climate it is getting ever harder for young people to have the opportunities to get the decent science education required to get them to that point.

Yours, honestly,

David Wiltshire