Re: [asa] The Multiverse - Physics or Metaphysics?

Though I'm not competent to comment much on the merits, since you mentioned
Lee Smolin, his book "The Trouble With Physics," which I read last year, is
a great read. He convincingly argues that string theory isn't really a
strong theory as "science" (convincing to me at least) and includes a very
interesting discussion of the sociology science and theory development.
(Amazon: http://tinyurl.com/2weed3)

On 9/10/07, Iain Strachan <igd.strachan@gmail.com> wrote:
>
>
> > If I understood, you are referring to string theory as "the most
> > successful cosmology." I would caution care here, because string theory has
> > not made any testable predictions and so it is dubious that it can claim any
> > success at all. It has been formulated to be consistent with what we know
> > in nature, but in trying to make it consistent, so many unobservable
> > dimensions and extra degrees of freedom had to be put into the theory *ad
> > hoc* that it ended up predicting this "string landscape" that is so
> > large that now you can get any answer imaginable and not just what we
> > observe. If the theory has to give you every possible answer in order to
> > also give you the one right answer, then it is questionable that it is
> > really a useful theory at all. This is why it has been called into question
> > by many leading scientists. You could have produced the same result using
> > any other framework other than strings. I hope you are aware of this.
> > There are many ways to formulate a framework that can include everything we
> > know plus a lot more. Simply keep adding unobservable degrees of freedom
> > until the framework allows the right answer. The key to science is Occam's
> > razor in which the fewest number of *ad hoc* assumptions gives you the
> > correct answer. So the critique on string theory is exactly correct, as
> > many scientists have formulated it.
>
>
> Again, this is very much along the lines I've been thinking. I see the
> same line of reasoning in my field of statistical pattern recognition, and
> data-fitting. Given any data set of any size, one can fit a model that
> agrees exactly with all of the data points by having sufficiently many
> degrees of freedom (adjustable free parameters) in the model. N data points
> may be exactly fitted by a degree N-1 polynomial. e.g. one can always fit
> a parabola (degree-2) through three points. But this observation can never
> tell us anything interesting about the data - for it to be interesting in
> any way (and to have any predictive value) the number of degrees of freedom
> must be very much less than the number of data points. Specifically, with
> the exact fit, one "overfits" the data, meaning that the function defined
> between the data points will oscillate rapidly and be highly sensitive to
> the measurement noise. By the same token, Koonin's paper invokes an
> unlimited number (as many as necessary) of parallel worlds (in the MWI
> sense) to get over the apparent extreme improbability of life.
>
> I just discovered the following quote on the Wikipedia entry for Lee
> Smolin, one of the strongest critics of string theory:
>
>
>
>
> *The scenario of many unobserved universes plays the same logical role as
> the scenario of an intelligent designer<http://en.wikipedia.org/wiki/Intelligent_design>.
> Each provides an untestable hypothesis that, if true, makes something
> improbable seem quite probable.* [3]<http://en.wikipedia.org/wiki/Lee_Smolin#_note-1>This
> again is exactly what I have been saying from the start (though Smolin is
> talking about string-theory based parallel universes rather than in the MWI
> sense, the argument is the same). Koonin's paper contains at the end a
> complete dismissal of Intelligent design. However, as Smolin's quote makes
> evident, what Koonin replaced it with was something that fails in just the
> same way.
>
> Quite pleased I had independently arrived at the same idea as Smolin. [Smug
> mode off]
>
> Iain
>

To unsubscribe, send a message to majordomo@calvin.edu with
"unsubscribe asa" (no quotes) as the body of the message.
Received on Mon Sep 10 20:51:33 2007