**Wave-Particle Duality: One does not have to invoke the particle concept to explain photon termination. Furthermore, it is counter-productive to do so.
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Wave-particle duality should remind us that physics involves the study of mass and energy. Energy may be kinetic (unstored) or potential (stored) and the same is true of mass. Sometimes entities of interest combine kinetic (rest) mass with kinetic energy, the projectile being an obvious example. But there are entities that have kinetic mass or kinetic energy, but not both. These are called *"pure" entities* in ontology.

Energy is pure when it is devoid of rest mass (i.e., electromagnetic radiation). Mass is pure when it is devoid of kinetic energy (matter that is stationary for an observer). *Pure entities therefore are the photon (no rest mass) and the inertial mass (no kinetic energy).*

The pure energy entity and the pure mass entity share a certain formal equivalence even beyond E = mc^{2}. This similarity/equivalence is founded upon the fact that that mass is quantized and extends over a space interval (rest mass requires a space interval), while energy is quantized and extends over a time interval (photon occurrence requires a time interval). But their formal equivalence goes deeper than that.

*Pure entities always store their opposite number* and this gives them a kinetic identity and a potential (stored) identity. Thus inertial mass has kinetic (rest) mass, but it also has stored/potential energy: thermal energy, displaced orbital electron energy, etc. The photon has kinetic oscillatory energy but it also has potential (relativistic) mass.

In addition to having dual identities, kinetic and potential, *pure entities are stationary in one dimension and progress in the other.* Special relativity tells us that time stands still at the speed of light hence the photon is stationary in time but of course it progresses at the maximum rate in space. Special relativity also tells us that inertial mass is, by its own measure, stationary in space but of course, it progresses at the maximum rate in time (were the mass to acquire velocity its clock would slow down).

Inertial (rest) mass is an existing pure entity and because it exists over space and progresses (persists) in time it possesses the field form. On the other hand, the photon is an occurring pure entity and since it occurs (oscillates) over time and progresses in space it possesses the waveform.

*The kinetic identities of pure entities are unaffected by progression in a dimension.* Certainly the rest mass of the inertial particle is unaffected by its progression in time. Equally the kinetic energy of the photon is unaffected and undiminished by its progression over three dimensional space. Thus a photon from a distant star may spread across innumerable space paths with no attenuation of its kinetic energy (its frequency is undiminished). This tells us that *the kinetic identity of a pure entity is both orthogonal and common to all progression paths while it is the potential identity that actually traverses those paths.* Photon kinetic energy (occurrence/oscillation) is common and indivisible for all space paths whereas photon potential mass is able to expand (and attenuate) to fill all space paths.

*Photon travel in space is actually the progression of waveform potential mass.* This waveform is a spatially continuous occurrence spreading over all available paths with the local intensity of the wave determining the likelihood of potential mass release (conversion from potential mass to kinetic mass). Waveform potential mass is physically real and has a dimensional presence (hence wave interference) just as field form potential energy (e.g., electrostatic charge) is physically real and has a dimensional presence. But as a pure occurrence, waveform potential mass is unencumbered by anything substantive and hence can collapse instantaneously over unlimited distances.

We are finally in a position to understand the physics behind wave and "particle" duality. A single photon moving through space and encountering a double slit in front of a target screen is actually a space-progressing wave of potential mass. This single photon wave passes through both slits, interferes with itself and fans out creating a pattern of high and low wave intensity (probability). *The photon's termination on the target screen is simply the point release of stored photon mass which gives the (false) impression that this is simple (classical) particle/projectile impact.* The location of individual photon termination is random, but the probability of photon termination (mass conversion) is always higher in those regions of high wave intensity.

It is the space-continuous nature of photon potential mass that permits a photon to "take all available paths." A compelling example of this is a single photon being split by a half-silvered mirror and taking two different paths in an interferometer. An analysis of this is here.

*Final Thoughts:*

1. Photons can only terminate by interacting with matter through the process of release/conversion of stored mass to unstored mass. The former is space continuous, the latter is space discrete. When physicists first became aware of the space-discrete nature of photon termination they immediately adopted the familiar (and classical) model of projectile impact. By convincing themselves that photons were particles whose wave behavior could be explained away ("superposition") they tied themselves in intellectual knots for generations. Today many of them embrace the contradiction of particle versus wave and won't give it up easily.

2. The reader may object that high energy electrons or neutrons are certainly particles and they mimic the behavior of photons in a double slit. That is true, but such particles have very tiny rest mass and comparatively large relativistic mass and the latter, of course, is still waveform potential mass. This topic cannot be covered here but is covered in the book.