Physicists themselves are divided on this question. On one hand M theory offers a quantum theory of gravity and an explanation of how the other forces are related and their characteristics but NOT, crucially, their magnitudes. Supporters (enthusiasts) are convinced that M theory is the real deal and will come into its own when the necessary mathematical techniques have been developed to solve equations in 11 dimensions. Sceptics say that it is just a mathematical construction without physical significance because it makes no testable predictions. Fence-sitters are, like fence-sitters everywhere, waiting to see what happens. As far as an observer can tell there has been a drift of supporters to fence-sitting and of fence-sitters to scepticism. This is because there has been little progress as the maths is proving intractable and some academics who have careers to worry about have spent 15 years or more on a subject that may yet turn out to have been of no value. The drift has accelerated recently because it was hoped and expected that the European LHC would have given a hint of the existence of several new particles that would have given Physics and M theory a boost. This seems to imply that M theory indicated that these new particles ought to exist but I find this odd. Either a theory predicts something or it doesn't. Most physicists were hoping for some particles that might have been candidates for the WIMPS (Weakly Interacting Massive ParticleS) that are responsible for the dark matter that comprises about 20% of the mass of our Universe or for the dark energy that makes up about another 75% but .... not a sausage! This depressed a lot of physicists who feel that physics need some new discovery that they can all work on.

A number of physicists are angry bout M-theory because they think it has lured to many of the best young brains to work on a useless theory to the neglect of some of the real issues in physics like the anthropic principle, the source of the acceleration in the expansion of the Universe, dark matter and the nature of time.

thanks for your informed response. I tend to think philosophical thought would have quite a bit to say about the state of physics today-which is why I thought I would ask the question. M-theory puzzles me too much--I am perhaps missing something, but it seems to be an effort to find reality through math alone. While it does appear that "God is a mathematician," I do agree with those that would re-focus the science to questions, such as the anthropic principle, which is a philosophically difficult concept, at least for me, to swallow. Some theories in physics today, I tend to think, look too much like the "coincidence" found by Galileo and Newton that the force of gravity on an object just "happened" to increase proportionately to its mass, such that all objects accelerate at the same rate in a gravitational field, Similarly, I am troubled by dark matter. I am sure there are philosophically-oriented physicists who fear that in our search for dark matter we are looking once again for the "luminiferous ether." I cannot help but think that Einstein really did have it right, philosophically speaking, although he knew, himself, that general relativity didn't explain quantum mechanics. I venture to guess Einstein didn't much care for quantum physicists that simply pointed to equations and deduced from their experimental accuracy alone their ontological correctness. God is, after all, a mathematician, but, I am drawn to Einstein in thinking that God is no gambler. I don't think He tosses dice. But, either way, the question is fascinating. I think open-minded physicists have a tremendous opportunity to revisit some of our most basic assumptions--as you say--on the nature of time (and, similarly, the nature of light.) I think there are tremendous discoveries out there to be made.

Timothy - I am,a scientist, not a philosopher. I like evidence and, if possible, proof in order to accept something. I am also a chemist and then a biochemist but when I was preparing for Oxford it was normal to do one or even two years after A levels so we did first year university level and a bit beyond in maths and physics as well as chemistry while still at school and this was maths of 1958 standard not 2013! It has nothing to do with intelligence but we had to work hard and deal with topics in hard detail and not as woolly concepts. Physics and cosmology are two of my subjects of interest. You are right in the sense that physics is grappling with important subjects at the smallest and largest scales where evidence is hard to find and usually indirect. This forces (or tempts) them into theories like M-theory and other untestable ideas. Hence philosophers feel entitled to join in. The weak anthropic principle seems to scientists to be the only way to account for the fact that the strengths of the physical forces seem to be perfectly tuned for intelligent life. No laws have been found yet that allow us to predict the forces and, if we constructed a million universes using random values for the force strengths, few if any of them would contain any physical structures, much less life of any kind.

Unless you believe in a God Creator (which transfers the problem but does not solve it) the Anthropic principle is all we have.

There are questions and debates on all these subjects and on the nature of time that you might like to read.

Stephen--thanks for your help with this question. I really appreciate it. I am of course, as a non-scientist--one of those types that feels "entitled to join in," so to speak. Unfortunately, I focus on the study of physics and not chemistry. This, perhaps, has narrowed my view too greatly. In any event, I completely agree that understanding of the underlying mathematics is crucial to being able to assess the relative merit of a scientific theory. This is, perhaps, why I am biased a bit toward Einstein. The math is, to me, more intuitive (although, I agree, it is old). Even so, general relativity has a particular-albeit, decidedly non-scientific-appeal to me in that (I venture to guess) it can be deduced both from philosophical and scientific viewpoints. (Assuming the philosopher is, of course, willing to study tensors--any philosopher of science should be so willing, in my view). I often compare GR to the Standard Model. I respect the SM as one of mankind's greatest achievements, though it does not, to me, seem to have the same intuitive appeal (even after you work through the maths of it). Nonetheless, the SM is, to my knowledge, the most accurate physical model ever developed. So it must be judged a philosophical and scientific success on those terms. Evidence, which is key to scientists and philosophers of science certainly favors both GR and the SM. And, yet, they differ in a qualitative sense I find difficult to describe.

As I mentioned, I am not drawn to M-theory, but I confess the maths there are beyond me. I do find the Weak Anthropic principle interesting. Can you point me to any readings that might summarize the state of the principle today? It need not be a layman's article, just somewhere I can develop a better understanding of the state of cosmology today. My knowledge is limited to GR, so I would like to expand on that. (Oh, and my references to God did not indicate a solely theistic viewpoint. I use God as a means to literally indicate my (admittedly philosophical) belief that the universe is not random. A belief that I should, perhaps, check until I am more versed in current cosmology.

Timothy - I can't tell if there is irony in your reply but, if there is, it is entirely justified! I do not intend to disparage philosophy. Indeed at Oxford in 1958 - 67 Philosophy and classical languages ("Greats") was the senior subject and sciences were the johnnies-come-lately. Philosophers realised that the flow of time is an illusion long before Einstein and Gödel proved it in 1949. Philosophers can also deal with subjects, such as ethics, to which science has only a little to contribute.

You are probable right that ToGR could be deduced by thought alone - as indeed it probably was by Einstein - but Einstein, who was, we are told, not much o a mathematician, was able to use the Riemann tensors to give the theory mathematical shape and make quantitative predictions that were verified subsequently to a large degree of precision.

The Standard Model is different in that it grew gradually as a collaborative effort between many scientists worldwide rather than being the creation of a single individual or team. The SM also makes predictions that have been verified but, as Wikipedia points out, it is incomplete an is likely to be tweaked and adjusted as the years go by and we learn more.

M Theory is (I think) the latest incarnation of String Theory and s really a mathematical development of an idea first proposed n the 1960s. Sadly it has remained as just a mathematical model of an idea, whose biggest attraction is that it delivers a quantum theory of gravity. It has, on the other hand, as several physicists enjoy pointing out, yet to deliver a testable prediction.

At the moment it's a bit like an intriguing parcel with the wrapping torn at the corners to reveal glimpses of what look like alluring contents but which we do not yet knowhow to open or what we'll find if/when we do. At present the maths is beyond not just you but everyone else as well.

The Anthropic Cosmological Principle evolved as a possible explanation of the fact that band of strengths of any of the apparently unrelated physical forces or of the quantities of certain key components of the Universe within which it can exist is very narrow and the band within which life can exist is even narrower. In fact the requirements for intelligent life are so demanding that a few scientists think that there will be very few if any other places in our universe where it might be found.

As for reviews of these subjects … I am not a specialist in any of them, although I can just about follow them. Therefore, like everyone else, I rely mostly on books. Scientifc Amercian often has articles by specialists which are mostly excellent and I have a digital subscription t sciam for less than $20 this year, for which you get a free download of the digital (pdf) version of the magazine plus access to all previous issues and a number of special articles or reviews.

WAP - The book to which I always refer when I need facts is "The Anthropic Cosmological Principle" by John Barrow and Frank Tipler, published in 1986 and revised in 1996. This has numbers and (accessible!) maths. More up-to-date and qualitative is "The Goldilocks Enigma" by Paul Davies. I have the book but have not read it yet. Two Sciam reports are "The future of String Theory", which goes into how ST allows for multiple Universes and "Parallel Universes" which is about how observations lead us to conclude that there must be a lot of Universes at least.

Lee Smolin believes that Black Holes give rise to new Universes that are not so different from their "parent". He has tried looking at universes that are most likely to produced a lot of BHs and those like ours come high up. See "The Life of the Cosmos" by Lee Smolin (1997).

Good luck!!

thank you for taking the time to give me direction on this. I really wasn't intending irony--more like Socratic inquiry. I cannot really know with certainly whether I am completely missing the point--so I like to be sure. Thanks again for the discussion, I've been taking a much closer look at these questions as a result.