I think that a good part of the discussion of this topic would be unnecessary
if we realize that the word "unlearning" is a very unhappy choice of terminology
when describing the progress of Physics. In most cases, the appearance of a new
physical theory does not cancel the previous one. Learning QM or SR does not
involve "unlearning" classical mechanics. No engineer will describe the motion
of a street car using the Schrodinger equation or relativistic dynamics.
Classical mechanics is much more than merely a special case of QM - it is a
necessary element of its foundations (see, e.g., Landau-Lifshits textbook). The
same can be shown about the relationship between classical mechanics and SR.
Even in the relativistic domain, F=ma and P = mv are not cancelled by SR, - just
the concept of mass has been generalized. Learning about spacetime is not
unlearning the relativistic effects - length contraction and time dilation are
not cancelled by spacetime - quite the contrary, they form its physical
underpinnings. Learning the GR is not unlearning the SR. Most good textbooks on
GR start with SR. Even learning that the Earth is round is not unlearning that
it is flat - for all practical purposes it is flat within a sufficiently small
area, and no architect designs a building using the concept of round Earth.
Similarly, learning that acceleration of free fall is mass-independent is not
unlearning that the rate of fall increases with mass - the latter remains true
in the presence of atmosphere.
Instead of term "unlearning" I would prefer to emphasize that a new theory
does not cancel the old one but generalizes it and in doing so also determines
the domain of its applicability. So there is no need to unlearn anything -
moreover, that would destroy our understanding of the modern picture of the
world.
I think that we as physicists must be very careful when it comes to loose use
of the language, especially when communicating with non-scientists. I am afraid
that use of the term "unlearning" has to a large degree provoked a widely spread
view of science as something permanently cancelling its own previous pictures
and changing them with totally different ones, and therefore it cannot be
trusted.
I would suggest to discard the term "unlearning" as totally misleading and
giving downright wrong picture of scientific progress.
Moses Fayngold,
NJIT
________________________________
From: "Espinosa, James" <JEspinosa@mail.twu.edu>
To: Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu>
Sent: Thu, September 16, 2010 11:08:48 AM
Subject: [Phys-l] "Unlearning"
I always warn my students that it is more difficult to unlearn something old
than to learn something new. This is a fact of psychology. My hope is that
being aware of this fact will make them more careful in their thinking in
physics.