I thought this was a very interesting comment about physics texts and
what is taught, so I thought I would share it with you.
cheers
joe bellina
---------- Forwarded message ----------
Date: Wed, 28 Jan 1998 08:47:44 -0500
From: Dave Nartonis <compub@SHORE.NET>
To: Multiple recipients of list HOPOS-L <HOPOS-L@VMA.CC.ND.EDU>
Subject: Re: Kuhn's curse
Professor French's post encourages me to add to my recent note. Remarks on
the delayed investigation of DeBroglie's alternative can also be found in
Gerald Holton's Thematic Origins of Scientific Thought, revised edition,
chapter 4. (Please note the back-reference to Jammer.)
As I'm sure many on the list know, reading Galileo's own derivation of
circular inertia is a lesson in how science is done. Straight line motion,
he argues, cannot be natural motion because a circle is a simpler figure.
In addition, were bodies-left-to-themselves to move in straight lines, the
bodies comprising the world would eventually disperse. He then turns to
his thought experiment in which an object rolls without friction down one
inclined plane and up another. What if the second plane were horizontal?
The object would never reach its initial height and would roll for ever.
But what is horizontal? It is a plane everywhere equidistant from the
center of a spherical earth -- a circle. Thus, left to itself, a moving
object will move forever in a circle and this explains the motion of the
planets.
All the physics texts with which I am familiar say instead that Newton got
his first law from Galileo. Thus, students do not learn that Galileo came
up with the wrong alternative -- one might say "delayed the discovery of
the right alternative" -- because he adopted the wrong assumption about
simplicity and assumed that a ball rolling on a horizontal track is "left
to itself" rather than "pulled toward the earth." Why are students not
taught this? I think it is because (as Kuhn pointed out) the physics texts
are intent on teaching a fictional theory about how science is done -- that
it proceeds linearly, without dependence on philosophical assumptions, etc.
In my experience, Newton's discovery of universal gravitation can be better
appreciated if the student understands first that Newton was struggling to
reconcile the circular motion of the moon (already explained by Galileo)
with the presupposition of straight line interia.
Is it possible that the vigorous defense of complimentarity and irrational
rejection of the alternative was fueled by a hope that complimentarity
would restore human agency to some proper role in the physical world?
Dave Nartonis
compub@shore.net
Boston USA
617-450-3329