From: George Murphy (gmurphy@raex.com)
Date: Thu Oct 16 2003 - 17:06:42 EDT
Walter Hicks wrote:
>
> George Murphy wrote:
>
> > Walter Hicks wrote:
> > ..................
> > > If you can tell me a textbook that offers a theory that it clearly falsifiable,
> > > I will go buy it. And maybe tell me (and others ) what tests could falsify
> > > those current theories...............................
> >
> > I'm jumping into the middle here & belatedly at that, but there's a basic issue
> > that hasn't been addressed. Falsifiability (F) is a useful working criterion for
> > scientific theories but in the end it isn't adequate.
> >
> > The idea of F (Popper) is an advance on the naive idea that theories can be
> > tested simply b "verifying" them. F rules out theories which claim that phenomena are
> > caused by agents whose _only_ effects are the phenomena in question ("invisible demons"
> > e.g.) But it runs into problems with more complex theories. The basic difficulty is
> > that you can always avoid having your theory falsified by introducing additional
> > elements into the theory.
>
> Are you saying that F should be a necessary but not sufficient condition?
Sort of. But you don't falsify an research program, just one component of it.
& (as explained below) a research program can to some extent be "repaired" by modifying
parts that have run into trouble.
> > Case in point. You can maintain (against general relativity) that the geometry
> > of the world is always strictly Euclidean. That requires additional hypotheses about
> > effects of gravitation on rulers and clocks - & perhaps changes in these hypotheses as
> > new data are gathered. But no one can absolutely falsify the claim that the sum of
> > angles of a triangle is exactly 180 degrees.
> >
> > A better way of understanding how science works, IMO, is that of Lakatos, which
> > has been developed by Nancey Murphy (especially in _Theology in the Age of Scientific
> > Reasoning_) in application to theology. Essentially the idea is this.
> >
> > You have a "hard core", a theoretical claim at the center which you're going to
> > try to maintain in the course of investigation. & then there are surrounding theories
> > forming a "protective belt" which can be modified to protect the hard core. In the
> > above example, the hard core is strict Euclidean geometry (as a claim about the physical
> > world, not just math) & the protective belt is made up of ideas about the influence of
> > masses on rulers & clocks.
> >
> > So how do you ever decide if a theory is good or bad? It's not a matter of
> > evaluating a static theory but of an ongoing research program - new observations &
> > experiments & theoretical development. If your theory can continue to predict "novel
> > facts" (i.e., those not used in construction of the theory) with no - or slight -
> > modification of the protective belt then it's a progressive research program. If you
> > can't predict novel facts & continually have to be changing the protective belt to
> > shield your hard core from the implications of new data then your research program is
> > degenerating. & if it keeps on degenerating, eventually most scientists will abandon
> > it.
> >
> > One good example is steady state cosmology. In the 40s & 50s it had the merit
> > of being "more falsifiable" than BB theory because it made unique predictions about
> > things like counts of radio sources. But those predictions turned out to be wrong, & BB
> > theory predicted the MWB while classical steady state theory didn't. However, you can
> > introduce auxiliary hypotheses (our universe is just a fluctuation in the overall state
> > state, appropritae scattering of starlight by dust to make the MWB) to protect the hard
> > core of the state state theory - which is that the universe is, on the average,
> > unchanging - & there are still a few diehards who hold that theory. (Hoyle did up to
> > his death.) But most cosmologists think that the SS program is degenerating & the BB
> > progressive.
>
> Back in the 50's people who believed in the BB were ridiculed as believing it because of
> religious notions. At least that is the way it was at MIT.
Sure, there were some anti-religious motives behind the steady state theory.
But there were also some good reasons for it - like the fact that the Hubble time was
then thought to be less than the age of the earth. & the main proponent of BB at the
time, Gamow, certainly didn't support it for religious reasons.
But my point is that it was easier to falsify predictions of SS than of BB
because SS had a unique cosmological model & thus made specific predictions about
various observational tests, while the cosmology of general relativity (especially with
a cosmological term) allowed a wide range of models. SS proponents argued that this was
a point in favor of their theory - as in a sense it was.
> > I've got to get to a meeting & don't have time now to apply this to the
> > Darwin-Wallace theory of evolution (which, in any case, ought to be done by a
> > specialist in that area).
>
> That would be great. However, there are a lot of theological issues with evolution that are
> not as great with other fields of science. The very core issue of automatically excluding
> anything other than natural means raises the question of objectivity in the minds of some.
MN is, for good or ill, a general rule of procedure for most scientists, not
just those studying evolution.
Shalom,
George
George L. Murphy
gmurphy@raex.com
http://web.raex.com/~gmurphy/
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