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[Phys-L] Re: What is Scientific Process?



At 07:51 -0500 8/31/05, jbellina wrote:

Au contraire,
It applies as well to experimental science. The experiment you
design, or the observations you make are all done within the context
of your belief system, so there are lots of ideas and
expectations...I tend to avoid the h word.

The "h word"? Hypothesis?

When M and M did the speed of light work...actually they were trying
to measure the velocity of the earth relative to the ether, the
expection was that they would get a result. When they did not, they
looked to experimental error, and worked to improve their
experiment. Twenty five years later, after Einstein et al. the
person who was the then president of the APS repeated the experiment,
and got a positive result. But the dogma had changed, so he looked
for experimental error. Had his result been obtained 25 years
before, he would probably have not done so.

Isn't the issue with this particular discussion one of objectivity?
Experimenters can easily fall into the trap of seeing what they
expect to see, whether it is there or not. I think Bridgman was
arguing that experimenters not bring their prejudices into the
laboratory, not that you cannot have some idea of what results to
expect. In other words, be prepared to be surprised, and don't be
surprised if you are ( ;-)). It should go without saying that one
should look for experimental error even if you get the results you
expected, and one should not stop taking measurements just because
the results are what you expected (this rule has to be applied with
some discretion, however, otherwise no experiment would ever end).
And one should take special precautions to make sure that one hasn't
designed their experiment to guarantee the desired results,
regardless of what the actual situation may be. Langmuir had some
interesting things to say about this many years ago.

I think the desire to eliminate experimenter bias is why
"double-blind" is the gold standard of experimental science.

Hugh
--

Hugh Haskell
<mailto:haskell@ncssm.edu>
<mailto:hhaskell@mindspring.com>

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