From Aaron Sloman Mon Mar 25 21:08:06 GMT 1996
Newsgroups: comp.ai.philosophy
Distribution: world
References: <4irrit$gr5@www.oracorp.com>
Subject: Falsification (Was: Re: Open Letter to Penrose)

daryl@oracorp.com (Daryl McCullough) writes:

> Date: 21 Mar 1996 10:11:25 -0500
> Organization: Odyssey Research Associates, Inc., Ithaca NY
> ....


> Neil Rickert writes
>
> >>          But what exactly killed falsificationism?
>
> >Thomas Kuhn's book, "The Structure of Scientific Revolutions." Kuhn
> >showed that the historical evidence on how theories have been
> >retained or rejected does not support falsificationism.

[Daryl responded]
> I don't think that Kuhn's book disproves falsificationism. Popper
> and Kuhn were doing two different things: Kuhn was studying how
> historically, scientific paradigms develop, evolve and are replaced.
> Popper was trying to explain what it is that makes a theory
> "scientific" in the first place. In particular, he was trying to
> come up with a criterion which distinguished scientific theories
> from more general philosophical or metaphysical theories, which
> often appear scientific.

Actually, Popper himself "killed" falsificationism in its cruder
interpretations: he noted that lots of good scientific theories are
not falsifiable in the strict sense of making predictions which, if
refuted, would prove the theory false.

He was well aware that there are all sorts of moves by which such a
theory could be defended against refutaion, and often was, e.g. by
postulating some extraneous influence. If I remember correctly he
himself showed how exactly such a move led to the discovery of one
of the more remote planets, because the observed motion of
previously known planet did not fit the predictions based on
Newtonian mechanics. A similar observed falsification of predicted
motion of Mercury did not lead to the rejection of Newtonian
mechanics. It was not until Einstein came up with a BETTER theory
some time later, that Newton was acknowledge to be wrong (though
approximately correct).

I think Popper even pointed out that a number of good theories were
"born falsified", i.e. when they were first formulated there were
already known, previously observed, counter-examples. Yet the
theories survived, and the counter-examples were dealth with.

Imre Lakatos, Popper's pupil, elaborated on Popper's ideas in his
important paper on the methodology of scientific research programs,
which I think was published in the mid 1960s in a volume edited by
Lakatos and Musgrave, whose details I don't have handy.
Perhaps someone else will post a full reference.

I don't know how closely Popper agreed with his pupil, but Lakatos
claimed that the only coherent way to interpret Popper's views was
not as requiring scientific theories to be falsifiable, but rather
as requiring scientific research programmes to be "progressive"
rather than "degenerative".
    A degenerative programme leads to no new empirical results, just
        lots and lots of ad-hocery to protect theories from
        falsification.
    A progressive programme leads to new empirical results and
        possibly also gradual elaboration and deepining of the
        theory (or theories), whilst some of the time defending
        theories against refuted predictions by challenging the
        experimental apparatus, or postulating extra forces, or...
        etc.

The phlogiston theory of combustion was scientific, but unlike the
oxygen theory was not progressive, but degenerative, a point Kuhn
missed.


> I think that most of Popper's points are valid.

What he actually wrote (e.g. in the Logic of Scientific Discovery,
and in Conjectures and Refutations) is much better and more subtle
than the potted summaries of his views that most people read
elsewhere. Possibly also his views changed.

> .The hallmark of
> a scientist is the willingness to be proved wrong, to say "If
> such and such does not come to pass, I'll have to admit that my
> theory was wrong." This is an ideal, not a description of any
> actual scientists, who, being human, have their egos to deal
> with.

Also sometimes they have important afterthoughts when the prediction
is proved wrong. I.e. they manage to defend the theory.

I think the most important point in Popper's philosophy is that a
good theory should have lots of diverse consequences, which follow
from it in an objective fashion, not just because the author writes
things like "If my theory is correct then we would expect that...."
(which is for instance, very common in psychological literature, or
used to be when I looked at it.)

The consequences of a good theory should be logically or
mathematically deducible, if possible (though sometimes the required
maths is only developed later).

Whether the consequences are empirically falsifiable is a secondary
consideration.

E.g. a theory saying that certain classes of phenomena, defined
axiomatically are *possible* is not empirically falsifiable. For no
failure to observe something proves that it is impossible. The
theory may be very rich in the classes of cases whose possibilities
can be formally derived from it. Moreover, there may be a lot of
observable examples of such cases, all explainable within the same
generative framework. This could be a very good scientific theory,
even though it is not emprically falsifiable. (Popper acknowledged
that such theories could be important in the development of science,
even though he said they were metaphysical not scientific.)

I leave it as an exercise to the reader to produce a number
important examples of this sort of possibility-generating theory,
from the history of science.

Aaron