On Sat, 10 Mar 2007 11:34:36 -0600, Cecil Moore
wrote:
Maybe cause and effect? Cause and effect is indeed
missing in a lot of QED stuff. Not only do some
virtual particles move faster than the speed of
light but also apparently necessarily jump
backwards in time.

So-called Feynman diagrams represent antimatter particles (positrons,
anti-quarks, etc) as the corresponding "matter" particles going
backward in time. Of course no physicist actually takes this
interpretation seriously. Nor do I believe particle theorists take
virtual particles seriously. They are just a convenient
representation of the terms in a perturbation expansion. It is unclear
to me that virtual particles play a role in non-perturbative theories.

--John