Re: Please clarify Feynman's assertion of light behaving only as particle

Ray,

First let me remind you that virtually all light (across the spectrum) is
electromagnetic radiation produced by some change in energy/mass involving
a particle … usually an electron surrounding an atom; but they can be any
particle. These electrons and other particles have specific energy- much
like larger objects in our world. 

The difference with the small energies associated with atomic particles is
that their allowed states do not define a continuum. This means that they
cannot exist with any amount of energy, but must make transitions between
two of those allowed. This has often been described as a toy working it's
way up or down a flight of steps. It can rest on any step, but not hover
somewhere in between.

With the light coming from an excited object, each electron contributes to
the stream of light in the form of a wave packet that has a beginning and
an end. This length represents the time required for the electron to make
its transition. Even this is not "instantaneous". However, the electron's
release is a finite event and produces the "photon" of light. It is
confined and is the "particle" in question. Whether a bulb filament or the
surface of a star, each element produces a very small amount of light
during each period of excitement followed by a period of decay. Any
electron may repeat this process many times, but each cycle has its own
discrete ejection of a light particle. The particles have wave
characteristics, but they travel as discrete bundles of energy and are best
thought of as such.

By way of examples: 
     psychologists think in terms of individuals vs. sociologists who think
in terms of group dynamics.
     engineers think in terms of gross objects vs. chemists who think in
terms of the atomic structures.
     biologists think in terms of the colors/wavelengths of light needed
for photosynthesis vs. Feynman who would be thinking of the photon energy
needed to affect each atomic transition.

Certainly for his work (and the work of those to whom he spoke) Feynman's
expression was most valid.

Do you see a forest or trees? Two separate forests can each be made of the
same species, cover the same area and grow to the same height. However, a
timber company would have no interest in the one with ten times as many
trees that are crowded and skinny. Rather they would go for the one that
had been thinned to allow thick trunks.

I hope this helps,
Gene Ewald