Geoscience Reference
In-Depth Information
must be possible to disprove, or falsify, the theory.
3
For a theory to
qualify as part of science, it must be possible to devise tests that, if
a theory is wrong, will reveal it as wrong. If no such tests can be
devised, then the theory is not useful, at least for the time being.
This is one reason why premature theories languish: No one can
think of anything useful to do with them. Popper did allow that the-
ories could be "corroborated"; that is, they could prove their mettle
by standing up to a succession of severe tests. Corroborate is a good
word—it means "to strengthen or support with other evidence;
make more certain." Corroboration falls short of proof, but shows
that research is heading in the right direction.
Though philosophers and historians of science debate the utility
of Popper's formulation and are apt to go on doing so, it jibes with
our common sense to say that science advances not by proving the-
ories right but by weakening them until they are falsified. Looking
back at the history of science, it is clear that this is the way it works.
Yet if one were randomly to select a scientist at work and ask, "What
are you doing?" one would be apt to get the answer: "I am confirm-
ing such and such a theory." In their daily lives, most scientists try to
confirm or extend theories, not to falsify them. In part this is
because scientists are rewarded for breakthroughs, not for falsifica-
tion. Rewards aside, however, human beings will not spend long
hours and entire careers searching for falsity. Thus a contradiction
exists between the way individual scientists behave and the way sci-
ence as a whole evolves—as the cumulative result of the work of all
scientists. A host of them, each trying to shore up their favorite the-
ories, will in time lead to the falsification of the weakest, to the great
disappointment of its proponents but to the advancement of science
overall.
A
LVAREZ
P
REDICTIONS
The Alvarez theory revolves around two key hypotheses: (1] 65 mil-
lion years ago, a meteorite struck the earth, and (2) the aftereffects
of the impact caused the K-T mass extinction. Since one can accept
the first without accepting the second, they need to be kept sepa-
rate (although the Alvarezes did not). In the rest of this chapter,
I will examine the evidence for the first half of the theory. (The
second half is covered in Chapters 8, 9, and 10.) Although Luis
Alvarez himself identified 15 pre- and postdictions, not all are of
equal importance. I will focus on six predictions that if confirmed
would be especially corroborative and that can be identified largely
by using common sense. If several of the six predictions turn out to
