Gary R., Helmut, list,

I think that that's pessimistic and that Peirce would agree. The problem for string theory and any other theory of quantum gravity is that, for people to test its distinctive predictions with a collider, the collider would need to be as big as the observed universe; so the predictions are meaningful in principle but apparently not in practice for us. Yet Peirce would remind us, as he did in "F.R.L." https://web.archive.org/web/20120106071421/http://www.princeton.edu/~batke/peirce/frl_99.htm , that Comte said that people would never discover the chemical compositions of the stars and soon enough spectroscopy of starlight showed people the chemical compositions of the stars. Of course, Peirce makes no firm promises about how long a given line of inquiry will take.

According to Wikipedia, the Planck length is, in principle, within a factor of 10, the shortest measurable length – and no theoretically known improvement in measurement instruments could change that. But some physicists have found that that's not quite as much of a barrier as it may seem to be.

From "7.3 Billlion Years Later, Einstein's Theory Prevails" by Dennis Overbye, Oct. 28, 2009, New York Times http://www.nytimes.com/2009/10/29/science/space/29light.html?_r=1 :

   [Begin quote]
   Until now such quantum gravity theories have been untestable.
   Ordinarily you would have to see details as small as 10⁻³³
   centimeters — the so-called Planck length, which is vastly smaller
   than an atom — to test these theories in order to discern the
   bumpiness of space. Getting that kind of information is far beyond
   the wildest imaginations of the builders of even the most modern
   particle accelerators, and that has left quantum gravity theorists
   with little empirical guidance.

   "What’s really lacking," Dr. Michelson explained, "is a laboratory
   experiment that tells us anything. So we have to use cosmology: we
   use the universe as the lab."
   [End quote]

The experiment's results

   [...] suggested that any quantum effects in which the slowing of
   light is proportional to its energy do not show up until you get
   down to sizes about eight-tenths of the Planck length [...].
   [....]
   Indeed, other physicists said that even this model would not be
   ruled out until the size limit had been set much below the Planck size.

Then in October 2014, "Test of Lorentz invariance with atmospheric neutrinos" https://arxiv.org/abs/1410.4267 set the limit up to seven orders of magnitude lower than the previous estimate ("eight-tenths of the Planck length" according to the NYT above). So Lorentz symmetry is shown to hold, down to a length on the order of 8∕10,000,000 of the Planck length.

How many would have thought that possible ten years ago? I myself, even having read the NYT article and the 2014 abstract, then got mixed up and said that the 2014 paper was what put the limit down to 8∕10 of the Planck length. I think I got mixed up because 8∕10,000,000 of the Planck length seems hardly credible.

Best, Ben

On 12/10/2016 6:13 PM, Gary Richmond wrote:

Helmut, list,

Helmut wrote:

    The hypothesis is dark matter, but there is no dark matter
    available for experiments. Also the string theory is not
    verifiable with experiments, because the hypothetic strings are
    smaller than anything detectable. So nowadays physics is somehow
    comparable with medieval scholastic theology.

Sometimes some of these postmodern theories (how many string theories have been proposed now?--I think over 12; and 'dark matter' seems almost an oxymoron), many of these mathematical-physical theories seem to me more closely related to science fiction than to science. It doesn't mean that some of them might not be 'true', but in at least certain cases (such as string theory) there's no way in which we'll ever know.

But, on the other hand, just as Peirce's early cosmology is quite interesting and highly 'suggestive'--at least to some folk--of how things may *be* or *have come to be*, so some of these mathematical-physical theories are as well.

I personally prefer science fiction (which I very much enjoy) expressed as 'pure' literature, film, etc. (even as it mixes in some of the physics such as that just mentioned above).

Best,

Gary R

Gary Richmond

*Gary Richmond
Philosophy and Critical Thinking
Communication Studies
LaGuardia College of the City University of New York
C 745
718 482-5690 *

On Sat, Dec 10, 2016 at 5:30 PM, Helmut Raulien <[email protected] <mailto:[email protected]>> wrote:

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