Adam: We are no longer faced with a Newtonian world where a
few laws of dynamics and the law of gravitation could make sense
out of reality. In quantum mechanics, the theorist confronts a
long list of concepts that must be organized and reconciled:
space, time, continuous, discrete, waves, fields, particles,
mass, energy, radiation, and the uncertainty relation, to name
just a few. The task is intimidating.
Max: But something tells me you don’t think it
Adam: I don’t think it impossible, but I do think that
what’s needed is a new perspective, a different approach, a
Max: And that is where the method of Einstein comes in?
Adam: Exactly! Whereas Einstein compared the photon gas and
the molecular gas in terms of thermodynamic behavior, I think we
can compare them in terms of the quanta they contain and how
those quanta exist or occur in space and time. Are you ready to
accompany me in this analysis?
Max: I am, but I’ll be following your lead.
Adam: A beam of light is a photon gas, and this beam may
consist of many photons or just a single photon. Its counterpart
is a molecular gas that may contain many molecules or just a
single molecule. Of course, if our two gases have but a single
member, no internal interactions are possible. Otherwise, the
quanta in our two gases interact with each other in a way
characteristic of the type of quanta involved. Of course, I use
"gas" in the extended sense so that a molecular solid
or liquid also qualifies. These two gases are special because
they just might include everything that exists and occurs.
Max: ...how are you proposing to analyze them differently
from the way Einstein did?
Adam: Einstein compared the statistical distribution of the
energy that characterizes each gas. I propose comparing the two gases
not in terms of traditional physics but in terms of ontology.
Ontology, you will recall, is usually defined as the study of
being, of that which exists. As a physicist, I insist upon
expanding the scope of ontology to include that which occurs.
Hence, an ontological analysis of our two gases is an inquiry
into how each of them exists or occurs within space and time.
Max: This strikes me as more philosophy than physics.
Adam: Perhaps it is both. In fact, physicists adopt and use
ontology whether they know it or not. Nineteenth-century
physicists embraced the ontology of classical physics which
clearly differentiated between existence and occurrence, and
space, time, and causality all appeared well understood. At the
turn of the century, new experimental evidence cast doubt on
those assumptions, and it has been a struggle ever since to find
a new understanding, a new ontology. I maintain there is an
ontology for quantum mechanics although few would seem to be
searching for it.
Let me restate my intentions. We know the entities of physics
must either exist or occur and they must do so in space and in
time. These entities are composed of both mass and energy, and
they display such characteristics as storage, conversion,
interaction, and discreteness or continuity. The study of these
characteristics as they relate to existence and occurrence is
what ontology should be for the physicist. No one that I know
undertakes such an examination. It may sound a little like
philosophy, but such an inquiry has some very significant
consequences for the physicist.
Max: Can you give me an example of how an ontological question
is relevant to physics.
Adam: Sure. Take the photon passing through a double slit and
impinging on a viewing screen. During flight, the photon appears
to be an occurring wave that is space continuous. Upon impact,
however, the photon appears to be an existing particle that is
space discrete. The apparent transformations of the photon from
occurrence to existence, and from continuous to discrete are
ontological problems in that they involve the ontological nature
of reality. By itself, physics is not prepared to address such
problems. Ontology is. The two disciplines complement each other.
Ontology provides certain constructs and abstractions that
physics lacks, and physics provides a rich set of quantum states
and processes whose ontology can be analyzed.
Adam: ... We first need to decide on the forms
our two gases naturally assume. The photon gas is the easiest
because it always displays a waveform, whether it is composed of
many photons or a single photon. We can see this in diffraction
experiments in which both a beam of light and a single photon
diffract owing to their essential wave character or form. To have
a photon with its undulatory frequency and velocity is to have a
waveform. Putting aside for the moment the photon's putative
"particle" characteristics, I insist that the photon is
actually an energy wave and so, by extension, is the photon gas.
The problem then is, what is the form for the molecular gas? ...
The molecule is a mass field and so, by extension, is the
In general, the field or the wave as form is independent of
the quanta that constitute it. Consider the waveform: one may
have sonic waves, water waves, and electromagnetic waves. The
first two examples involve different types of material quanta
creating a wave; the last example involves radiation quanta
creating a wave. Yet all have a phase velocity and are capable of
diffraction, interference, and reinforcement. A similar
constituent independence holds true of the field; its quanta may
be either different varieties of molecules, or radiation energy
quanta of the magnetic or electric variety.
If you think about it, the waveform has become a generalized
concept--for material and radiation quanta--because its
undulatory and velocity characteristics are easy to spot and
identify. In contrast, the field form was developed by Faraday
only to explain the electric-magnetic action upon a particle at a
distance. But if you can take the energy quanta of electric
charge distributed over space and call it a field, you can do the
same with the mass quanta of the molecular gas. Waveform and
field form as I use the terms are abstractions; they are the
formal characteristics of physical waves and physical fields
Max: So you are going to take the quanta-independent abstract
forms of wave and field and examine their consequences for a
variety of what you call "ontological properties?"
Adam: That is correct But, remember, abstract forms become
real once quanta are involved. A matter field with real quanta
actually exists, and we may then call it an "ontological
field" to distinguish it from an abstract, Platonic or
mathematical field. Similarly, a radiation wave with real quanta
actually occurs and may be called an "ontological
wave." ... In effect, the ontological
viewpoint separates the form of an entity [wave or field] from
the quanta [matter quanta or radiation quanta] that give it
Max: Much of physics, including most of particle physics,
deals with projectile motion where the particle in motion has
both a rest mass plus a mass deriving from its energy of
Adam: Projectile motion is complicated. It’s a mixture
of states (existence, occurrence) and a mixture of forms (wave,
field). We shall deal with these conditions presently. But first,
I think we’d better make sure that we both share a full
understanding of all those concepts we have just been
discussing--existence, occurrence, field, wave, potential,
kinetic, mass, energy, matter, and radiation. The best way to do
that, I suggest, is to concentrate, as Einstein did, on the two
special, "pure" cases: static matter field and moving
photon wave. Once we understand them, projectile motion will
appear a lot less confusing. For the time being, we must deal
with the restricted universe of our two gases...