Ralph D, particle physics, and BS

Rahul Mahajan rahul at hagar.ph.utexas.edu
Thu Jun 15 21:05:52 MDT 1995


Hi, guys. It's been a while since my last post -- how do you guys have
lives and post so often on this list, anyway? I wasn't sure if I would post
again, but, Ralph, your repeated barbs at particle physicists forced me to
respond.
   First of all, Ralph, a hearty thanks for blowing up Juan Inigo in a
largely satisfactory manner. Not to offend Juan, but I think a sure test
for brain damage would be: if you can understand his posts, you've got it
(or you've got postmodernism, which of course is brain damage suborned by
reactionary capitalism).
   Now, then. Ralph, you frequently brought up the question of knowledge of
science when replying to Juan, which I think is highly appropriate,
especially when you're talking about physics. The material is so difficult
and the state of popular writing so execrable that you simply cannot learn
enough physics to talk seriously about it unless you really learn it --
i.e., do all that math. In biology, for example, there is much detailed
knowledge necessary as a source of examples, or to understand things in
detail, but a layman can (by reading moderately technical stuff like
Scientific American) pick up a general understanding of many things
(perhaps excluding some molecular biology). However, reading _words_
written about physics is almost useless. For example, I've seen a lot of
mention of wave-particle duality even on this list, but nobody seems to
appreciate that the point is that the classically obvious or natural ideas
of wave and particle simply do not correspond to reality when it is looked
at at a deeper level. It's not that the electron is sometimes a wave and
sometimes a particle -- it's that the electron is something else entirely,
which can be described and understood to an incredible degree
mathematically, but not in words and not in terms of naive concepts.
   That said, let me, as a particle theorist, give you the scoop. (BTW, the
above is not meant as an argument from authority, just a clarification as
to what constitutes "knowledge" about physics). What I will tell you is
essentially gospel, i.e., I have not injected my own particular ideas
and/or feelings into it. To start, particle physics is the field of human
endeavour where the results are the most stringently tested and have passed
the tests the best. For example, quantum electrodynamics allows you to
calculate the magnetic moment of the electron to 10 or 11 decimal places
(significant figures) --  i.e., theory and experiment agree to that
phenomenal a degree. Circa 1975, a model (the standard model) had been
developed which was in complete agreement with all existing experimental
data and which furthermore predicted several major things that were later
found in pretty near exactly the places they were supposed to be. The
discovery, if it is valid (since it's recent, it certainly hasn't been as
well tested as previous discoveries), provides the last piece but one that
the standard model has predicted. Remember, when I say agreement with
experiment, I'm talking about hundreds of millions of data points
corresponding to thousands of different elementary partile reactions --
roughly as well tested as the sun rising in the east.That said, since then
there have been no experimental discoveries that necessitate modification
of the standard model, but theorists have not stopped working. They've been
making other models (string theory, etc.) that reduce to the standard model
(or something close to it) at low energies but that avoid the problems it
is clear the standard model will have (we know this through simple
mathematical analysis) at higher energies. These theories are as yet
completely untested -- in order to be tested, of course, they need to make
some new prediction at accessible energies, but the mathematical
sophistication we can bring to bear on them does not enable us to make
testable predictions from them yet. It is clearly understood by all
particle theorists that in the absence of such tests these theories are not
science in the same way as the standard model or the theory of evolution,
for that matter. We work on them in order to develop mathematical tools
that may have general applicability and in the hope that we can in time
understand string theories and similar esoteric ideas well enough to test
them. If some idiotic journalists give a very different idea, as they have,
it's not the fault of the scientific community (although there are one or
two grandstanders who should be horsewhipped). The state of cosmology is
very similar, except that it never contained any theory anywhere near as
well-tested as the standard model, although general relativity is still
orders of magnitude better tested than anything outside of physics and
chemistry.
    If you think the above was too pedestrian and doesn't address your
objections, then make some SPECIFIC statements about particle theory.

    I agree with you that a sharp distinction between natural science and
social science is pointless, although there do seem to be, sociologically
speaking, some very sharp delineations -- like if you do insect
sociobiology, you spend years making painstaking observations and try to
control for various factors, etc. whereas if you do human sociobiology you
can toss off unexamined derivative nonsense and call it science (witness
the fact that for 30-odd years nobody called Cyril Burt on the fact that in
his twin experiments he had correlation coefficients agreeing to the third
decimal place between different studies with different sample sizes).
Speaking, however, in terms of the way things should be done, clearly there
are gray areas, such as the behavioral sciences, and there is the fact that
all social sciences are constrained, sometimes strongly, by natural
science. Similarly, however, to lump all natural sciences together is
absurd -- often, evolutionary biology has a lot more in common with
anthropology or sociology than it does with particle physics. BTW, on the
subject of the canard about social perceptions and biases always affecting
scientific work, I would like to see someone tell me how my political
beliefs will affect my understanding of heterotic string theory.
    Even so, there is a serious divide, which is generally somewhere in the
middle of biology (there is no linear sequence of sciences, of course)
between those that use more or less quantitative methods (for real, not
like polling and utility functions) and frequently repeated, carefully
tested experiments, and those that don't. So, functionally at least, there
is a significant difference between saying that science has shown that DNA
is the genetic material of most life and saying that science has shown that
as capitalism advances, the rate of profit falls and the proletariat is
increasingly immiserated (is that a word), thus leading to a revolution.

Rahul




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