Re: [asa] What causes students to move from faith?

From: Ted Davis <>
Date: Wed Sep 13 2006 - 13:01:57 EDT

>>> <> 09/13/06 12:49 PM >>>writes:
First, at the time Ptolemy devise
the geocentric system, it seemed common sense, and given
the knowledge of the time, it was probably the most
reasonable model. Of course, there was no explanation
for how epicycles work and lots of other stuff, but all
of this is with 20/20 hindsight. At the time, the proposition
was quite reasonable.

In our own generation, we have no explanation for quantum
mechanics, so we also take as given what we observe and
try to go on and deal with problems we can address. Perhaps
there never will be an adequate explanation of QM, but at any
rate, we cannot find one right now, and so we simple accept it;
just as people in Ptolemy time would have accepted epicycles.

Ted comments:
Exactly so, Wayne. Let me elaborate on the first paragraph. Ptolemy's
work fell squarely within the ancient astronomical tradition that he
(obviously) helped to create. The attitude toward mathematical hypotheses
was that they were just that, mathematical (ie, geometric) hypotheses (ie,
useful fictions that aren't expected to be literally true). We have no way,
so they would have said in the Renaissance, directly to know how the heavens
work; the best we can do is to "save the appearances" using circles/spheres
in uniform motion. An instrumentalist, not a realist, position. The
realists, on the other hand, concerned themselves more with matter
theory--what makes up the heavens, etc, not how they actually move.

Epicycles, it's worth noting, survive well into the 17th century as a
standard part of Copernican (yes, I did say Copernican) astronomy. They
serve different purposes than they did for Ptolemy--they aren't needed to
get retrogression, but they are needed to modify otherwise purely circular
planetary movements into other shapes. Kepler used them until that point
when he realized, rather suddenly, that ellipses held the key.


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Received on Wed Sep 13 13:03:01 2006

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