Re: Disparaging Popper

["Matthew Bonnan" <mbonnan@hotmail.com>]

Brian "Philidor11" said:

> To paraphrase (sorry if I'm mis-stating), if certainty is measured by
> statistical confidence, 100% certainty is not possible.  But if that's 
> true,
> then in fact no scientific theory can refute or preclude the accuracy of 
> any
> alternative theory.  (I'm using the word theory in place of hypothesis on
> purpose.)  One theory may be only more likely than another based on 
> arguable
> criteria.  That proposition is troublesome.

Well, not exactly.  Yes, certainty in science is never 100% possible.  In 
all sciences, the hypotheses, laws, and theories are generalizations based 
on probablistic outcomes.  But, this doesn't mean that no scientific theory 
can refute or preclude the accuracy of any alternative theory, as you 
suggest.

Rather, we must remember that a scientific theory has five properties:  it 
is 1) testable, 2) falsifiable, 3) gives results that are repeatable, 4) has 
predicitive power, and most importantly for scientific theories only (not 
hypotheses and laws), 5) it has explanatory power.  If a new theory better 
EXPLAINS the portion of the universe we are investigating than an old 
theory, we do have a means of choosing one over the other, and it is not 
arbitrary.  Newton's theory of gravity explained many things, but Einstein's 
theory of gravity explained all the things Newton's old theory had, plus 
some things it could not explain.  Therefore, Einstein's theory of gravity, 
rooted in his larger theories about relativity and space-time, is selected 
because it has better explanatory power than Newton's.

Criteria I suppose are always "arguable," but the criteria (or better yet we 
should say data) are generally based on the amount of evidence from 
experiment, observation, etc., that would be explained by the theory.  No 
scientific theory is ever perfect, though, and that's what keeps science as 
vigorous a discipline as it is.

Think of dinosaur extinction theories.  They each have explanatory power to 
varying degrees.  Some attempt to explain dinosaur demise through 
gradualistic mechanisms, whereas others explain dinosaur demise through 
catastrophic global enviornmental upheavals.  I do not wish to get into the 
nitty-gritty of the various extinction hypotheses, but all can potentially 
be falsified.  If, for example, your theory of dinosaur extinction involves 
disease, how does that explain the corresponding extinctions of non-dinosaur 
organisms?  A more globally encompassing theory may better explain dinosaur 
AND other organismal extinctions, and so our disease theory may have to be 
modified or be rejected/falsified.

In any case, the power of a theory comes from its ability to explain, in our 
case, patterns in the evolutionary history of dinosaurs.  Theories that 
explain and account for all or most of the evidence are generally selected 
for, whereas theories that are contradicted by the evidence or fail to 
explain certain evidence that newer theories do are either modified or 
eventually rejected/falsified.

Good question.

Matt Bonnan
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