Darren New <dne### [at] sanrrcom> wrote:
> http://www.universetoday.com/72531/scientists-say-they-can-now-test-string-theory/

  While I know virtually nothing about string theory (well, string theories,
as there are many; the unified theory would be the so-called M-theory),
I find it a bit "unlikeable" for one reason.

  Newtonian mechanics are based modeling and testing direct observations
of physical phenomena. One could say that it starts from the observation
that gravity and interaction between objects behaves in a very consistent
manner, rather than being random or arbitrary. This very precise consistency
allows creating formulas to describe these behaviors. The formulas can be
immediately tested in practice. (For example, if a formula predicts that
dropping a weight from a certain altitude will take a certain amount of
time for the weight to hit the ground, you just can go and test it and
see if the prediction is correct. Moreover, you can perform the test
numerous times from different altitudes and see if the formula always
gives the correct result.)

  In other words, Newtonian mechanics are directly based on observation.
It's expressing with math what one can directly observe and measure. The
predictive power of these formulas is extremely significant and practical.

  Of course it was later observed that, while still behaving in a completely
consistent manner, not all natural phenomena behaved as described by the
Newtonian formulas. For example, the speed of light in vacuum does not
behave in a Newtonian way. (Of course Newton had no way of knowing this
because he lacked the technology to test it.)

  Special Relativity starts from the simple assumption that (besides space
being cartesian) the speed of light in vacuum is the same for all
(inertial) observers. That's about it. This is a rather fair assumption
to make because it's the result of a measurement (rather than being a
wild guess). From this simple assumption you can deduce the Lorenz
transformations (and from them the entirety of SR).

  Again, SR has strong predictive power which, although not as easy as
with Newtonian mechanics, can be relatively easily and directly measured.
You can set up tests and see if the results are as predicted by SR.

  Of course SR was lacking. It assumed inertial frames of reference and
didn't take any stance on accelerating ones.

  If I have understood correctly, General Relativity starts from the
assumption that the speed of light in vacuum is the same for all
observers regardless of their state (ie. inertial or accelerating),
and that inertial mass and gravitational mass are the same thing,
and that's about it. (Again, the mass equivalence is a fair assumption
to make because it's based on observation. The equivalence has been
known since the days of Newton, but it was unknown if it's just a
coincidence or whether there is a strong connection between the two.
Einstein started with the assumption that not only are they equal,
but they are actually the same thing.)

  While deducing the Lorentz transformations from the assumption of
c being the same for all inertial observers (and space being cartesian)
is relatively simple, deducing the GR equations from the further assumptions
is quite a lot more complicated and laborious, but in principle it's just
pure math, without further assumptions, "leaps of faith" or guesswork,
and hence not significantly more complex at a conceptual level.

  Again, GR as strong predictive power, which can be directly measured
with well-defined tests.

  GR has been *so* successful with its predictive power and successful
tests, that has long ago become the de-facto baseline for any new
theories in the same way as Newtonian mechanics were before it: Any
new theory has to have the same expressive power and give the same
predictions as GR, or it just won't cut.

  However, which observation or measurement is string theory based on?
As I said, I know next to nothing about it, but it just sounds to me
like string theory is based on *nothing* at all. It just throws a big
bunch of extra dimensions from nowhere, based on no measurement,
observation or other rational justification, and builds up a huge
bunch of random hypotheses based on these unfounded assumptions.
It almost sounds like the foundations of string theory is not on actual
measurements but on philosophical assertions. For example, the assertion
of 10 dimensions might have a *logical* foundation, but it's more of a
philosophical foundation than one based on actual measurements and
observations. It sounds more like metaphysics (in the philosophical
sense) than real physics.

  And why is it even called "string theory"? Shouldn't the proper term
be "string hypothesis"? String "theory" is *not* backed up by a wide
variety of observations, measurements, repeateable tests, correct
predictions and general acceptance in the scientific community.

-- 
                                                          - Warp

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