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Steven Weinberg on what we do and don’t know now

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At New York Review of Books:
http://www.nybooks.com/articles/archives/2013/nov/07/physics-what-we-do-and-dont-know/

Since the 1980s a tremendous amount of mathematically sophisticated work has been devoted to the development of a quantum theory whose fundamental ingredients are not particles or fields but tiny strings, whose various modes of vibration we observe as the various kinds of elementary particle. One of these modes corresponds to the graviton, the quantum of the gravitational field. String theory if true would not invalidate field theories like the standard model or general relativity; they would just be demoted to “effective field theories,” approximations valid at the scales of distance and energy that we have been able to explore.

String theory is attractive because it incorporates gravitation, it contains no infinities, and its structure is tightly constrained by conditions of mathematical consistency, so apparently there is just one string theory. Unfortunately, although we do not yet know the exact underlying equations of string theory, there are reasons to believe that whatever these equations are, they have a vast number of solutions. I have been a fan of string theory, but it is disappointing that no one so far has succeeded in finding a solution that corresponds to the world we observe.

Inflation is naturally chaotic. Bubbles form in the expanding universe, each developing into a big or small bang, perhaps each with different values for what we usually call the constants of nature. The inhabitants (if any) of one bubble cannot observe other bubbles, so to them their bubble appears as the whole universe. The whole assembly of all these universes has come to be called the “multiverse.”

These bubbles may realize all the different solutions of the equations of string theory. If this is true, then the hope of finding a rational explanation for the precise values of quark masses and other constants of the standard model that we observe in our big bang is doomed, for their values would be an accident of the particular part of the multiverse in which we live. We would have to content ourselves with a crude anthropic explanation for some aspects of the universe we see: any beings like ourselves that are capable of studying the universe must be in a part of the universe in which the constants of nature allow the evolution of life and intelligence. Man may indeed be the measure of all things, though not quite in the sense intended by Protagoras.

Such crude anthropic explanations are not what we have hoped for in physics, but they may have to content us. Physical science has historically progressed not only by finding precise explanations of natural phenomena, but also by discovering what sorts of things can be precisely explained. These may be fewer than we had thought.

Another productive day in the world of materialist cosmology.

2 Replies to “Steven Weinberg on what we do and don’t know now

  1. 1
    bornagain77 says:

    And,

    BRUCE GORDON: Hawking’s irrational arguments – October 2010
    Excerpt: Rather, the transcendent reality on which our universe depends must be something that can exhibit agency – a mind that can choose among the infinite variety of mathematical descriptions and bring into existence a reality that corresponds to a consistent subset of them. This is what “breathes fire into the equations and makes a universe for them to describe.” Anything else invokes random miracles as an explanatory principle and spells the end of scientific rationality.,,,
    Universes do not “spontaneously create” on the basis of abstract mathematical descriptions, nor does the fantasy of a limitless multiverse trump the explanatory power of transcendent intelligent design. What Mr. Hawking’s contrary assertions show is that mathematical savants can sometimes be metaphysical simpletons. Caveat emptor.
    http://www.washingtontimes.com.....arguments/

    The Absurdity of Inflation, String Theory and The Multiverse – Dr. Bruce Gordon – video
    http://vimeo.com/34468027

    Here is the last power-point slide of the preceding video:

    The End Of Materialism?
    * In the multiverse, anything can happen for no reason at all.
    * In other words, the materialist is forced to believe in random miracles as a explanatory principle.
    * In a Theistic universe, nothing happens without a reason. Miracles are therefore intelligently directed deviations from divinely maintained regularities, and are thus expressions of rational purpose.
    * Scientific materialism is (therefore) epistemically self defeating: it makes scientific rationality impossible.

    Of related not, ‘anthropic explanations’ (i.e. we just got lucky) can only be pushed so far;

    The Place of Life and Man in Nature: Defending the Anthropocentric Thesis – Michael J. Denton – February 25, 2013
    Summary (page 11)
    Many of the properties of the key members of Henderson’s vital ensemble —water, oxygen, CO2, HCO3 —are in several instances fit specifically for warm-blooded, air-breathing organisms such as ourselves. These include the thermal properties of water, its low viscosity, the gaseous nature of oxygen and CO2 at ambient temperatures, the inertness of oxygen at ambient temperatures, and the bicarbonate buffer, with its anomalous pKa value and the elegant means of acid-base regulation it provides for air-breathing organisms. Some of their properties are irrelevant to other classes of organisms or even maladaptive.
    It is very hard to believe there could be a similar suite of fitness for advanced carbon-based life forms. If carbon-based life is all there is, as seems likely, then the design of any active complex terrestrial being would have to closely resemble our own. Indeed the suite of properties of water, oxygen, and CO2 together impose such severe constraints on the design and functioning of the respiratory and cardiovascular systems that their design, even down to the details of capillary and alveolar structure can be inferred from first principles. For complex beings of high metabolic rate, the designs actualized in complex Terran forms are all that can be. There are no alternative physiological designs in the domain of carbon-based life that can achieve the high metabolic activity manifest in man and other higher organisms.
    http://bio-complexity.org/ojs/.....O-C.2013.1

  2. 2
    Robert Byers says:

    I don’t care about string theory but smell its not proven just like evolution.
    Its not proven like einstein stuff.
    So a experiment.
    Ask the string theory folks if its as founded or more founded on evidence as evolution?
    If they say yes then its not founded. If they say its founded like einstein’s stuff and evolution then make them prove it!

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