Positivism vs Realism

[Tom DiBenedetto]

James Francis Lyons-Weiler wrote:

>>       If I hypothesized that aliens manipulated the species'
>>       occurences, now that's a bold ad-hoc hypothesis.
>
>No James, it is oulandish, not bold. Popper uses the term boldness in
>a precise manner to refer to hypotheses which have great generality,
>great CONTENT, and thus great testability. They are bold because they
>seek to explain A LOT. Your alien hypothesis has none of those
>qualities.
>
>       Baloney!  If it were tested, and couldn't be falsified,
>       imagine the impact, the new information.

The new information would be simply this. Aliens manipulated the
distribution of this species. It is an ad hoc hypothesis, plain and
simple. It is bizarre and outlandish, but not bold in the Popperian
sense.
You want boldness? Hypothesize that aliens manipulate ALL species
distributions. Test that, and if not falsified, you have a lot of new
information, because you have explained a lot about the world. E=mc2
is a bold hypothesis not because it is bizarre, but because it seeks
to explain something about all manifestations of energy and matter-
it tries to say a lot. And by so doing, it is open to a lot of
testing; it is hugely falsifiable, testable, corroborable. And that
is why boldness is inherintly linked to corroborability, and is a
quality we desire in scientific hypotheses. Ad hocs are at the
opposite extreme (within the domain of scientific statements). They
say as little as possible beyond the evidence, and thus have a very
limited scope for testing.

>       Ad-hocness is a "for the time being" characteristic
>       of a hypothesis - like corroboration.

sorry, but that is just wrong. Ad hoc is Latin for "to this"; it
means "for the specific purpose, case, or situation at hand and for
no other". Refer again to the Popper quote I gave you (if you dont
trust your dictionary) ad hoc meaning "transcend the available
evidence as little as possible. Read his long critique of induction,
in which he refers constantly to ad hocness - it is a characteristic
of what the hypothesis says - how much beyond background knowledge it
goes, and that is directly proportional to testability.
Period.



Tom DiBenedetto                 http://www-personal.umich.edu/~tdib/
Fish Division                                   tdib at umich.edu
University of Michigan Museum of Zoology