From a basic causal perspective, all action requires an understanding of energy and forces. In terms of classical physics, this discussion would have been entitled: ‘Force Issues’, but within the context of the quantum model, they are described as interactions. However, both the classical and quantum models both consider four fundamental forces, or interactions, based on gravity and electromagnetism plus nuclear interactions classified as weak and strong, as characterised below, although the concept of gravity is not fully integrated into the quantum model.
More as a matter of semantic preference, this discussion will generally use the idea of a force because the concept can be quantified in terms of MKS units, as expressed in . However, before discussing these equations, we might ask whether energy is more ‘fundamental’ than a force and suggest that a difference in field potential between two points in space has to be a prerequisite requirement for a force to exist. If so, there must be a link between a force and energy from which a force [F], as defined in , might be quantified in terms of either an electrostatic [Fe] or gravitational [Fg] force as a function of distance [r].
We might consider  as the force around a single ‘particle’ associated with its charge or mass. In this context, there is an inference that this potential field must independently exist around [q1] or [m1], although it needs to be highlighted that this force can only be measured by a unit charge [q2] or mass [m2]. For completeness, we might show how the expression in  is translated into the potential energy [U] within either the electric or gravitational fields, as shown in .
Again, if we return to the idea that a force requires a potential energy difference [dU] between two point in space, or a field, we then need to question the fundamental nature of the potential energy between [q1] and [q2] or [m1] and [m2]. If it is argued that the concept of mass [kg] cannot be a fundamental unit, but rather a manifestation of an energy-density, we also have to question the nature of charge [Coulombs] as a fundamental unit of the quantum model.
But what about the other two nuclear forces, weak and strong?
While this discussion will not pursue the details of the weak and strong nuclear forces, it would seem that some of the fundamental causal issues being considered in terms of gravity and electric forces must also be applied to all forces, irrespective of whether we rename them as interactions. However, by way of brief outline, the weak force is linked to the process of radioactive decay, while the strong force is assumed to bind protons and neutrons within the nucleus. These forces were not known until the 20th century and, as such, the classical perspective was essentially limited to the concepts of gravity and electromagnetism. While, from a comparative perspective, the force of gravity is very weak, when compared to the other forces, it was generally assumed to be the only one that could scale beyond the microscopic universe and, as such, this relatively weak force becomes the only significant force at work within the macroscopic cosmos.
Note: Generally, it is assumed that most of the matter in the universe is electrically neutral, because atoms generally have an equal number of positive protons and negative electrons. However, in recent years, an alternative perspective that we might label as the Plasma Model has suggested that electric fields play a major role in the cosmological model.
So, having now simply introduce the scope of the four fundamental forces, or interactions, we shall return to the issues surrounding equation . Let us initially accept the assumption that the concept of a mass particle does not exist at the quantum scale, such that it has to be replaced by some form of energy-density structure. While we do not really know the details of this structure, both the quantum model and most wave models consider the existence of some form of wave structure, which empirical experiments support in terms of both frequency [f] and wavelength [λ] measurements.
Note: Based on the outline above, it is assumed that a particle does not have physical mass [kg], only its equivalence in terms of an energy-density. Based on a reversal of Einstein’s energy equation [m=E/c2], we have a way of possibly correlating mass to energy, which can also be extended within some form of wave model to explain the measure of both frequency and wavelength plus why quantisation of energy is observed in certain experiments.
However, what is not obvious in many of these models is how the concept of charge would come into existence and be an attribute of an isolated wave-particle structure, which in fundamental terms only appears to explain potential energy oscillating as a function of time. This said, we might have already suggested one possibility, i.e.
All forces are a result of a potential energy difference between two points in space, or a field.
Of course, within the scope of this review, we are seeking to discover whether there are any causal mechanisms, which might both support and explain the idea above. Therefore, this discussion will initially outline some basic ideas forwarded by the MMW model, the OST model and the EWT model. While it is highlighted that each wave model reviewed in website-3 might be said to forward various causal explanations, they all differ considerably in their details. We will start with the Matter is Made of Waves (MMW) model and make reference to a webpage called Active and Reactive Mass, which provides a speculative causal explanation of mass, as a wave structure, and why it is subject to relativistic effects. The diagram below reflects a particle wave-centre in motion, where this waveform is subject to a Doppler effect in the forward and backward directions, when in motion. This motion can also be subject to relativistic effects when the velocity [v] of the wave-centre approaches the speed of light [c]. While the link allows the reader to review the material themselves, a few paraphrased extracts will be used to outline some ideas.
Action and reaction forces can be unequal when subject to a Doppler effect. The Doppler effect on wavelength is defined by (1+β) and (1-β) in the backward and forward directions respectively. The combination of the active [a] and reactive [r] mass-energy equals the relativistic mass-energy [γm=a+r] and supports the idea that matter is made of waves.
In the model above, we might consider the mass of a wave-particle to exist in two hemispheres in 3D space, where the forward active mass-energy [a] is greater than the backward reactive mass-energy [r], when the velocity [v] is greater than zero. We might simply attempt to visualise the ‘interactive forces’ that might be created by various combinations of wave-particles with different phase relationships – see Phase Shift for more details. In the first animation below, we see the net energy-density between the two wave-centres is lower than the surrounding energy-density, such that this configuration might be seen as illustrative of an attractive force.
In the next animation, we see the opposite effect, where the energy-density between the two wave-centres is higher than the surrounding energy-density, such that this configuration might be seen as illustrative of a repulsive attractive force.
While these animations are only being presented as a speculative causal mechanism, it is interesting that such waveforms constructed from only oscillating potential energy might help explain both attractive and repulsive forces.
Note: Of course, it needs to be highlighted that while this model might form the basis of any fundamental force, or interaction, the MMW model never really expanded all the necessary details - see Electrostatic Fields, Gravity, Quarks and Protons for some further speculative ideas.
Next, we might attempt to briefly outline some of the ideas of the Energy Wave Theory (EWT) Model, which while sharing some similar concepts with the MMW and WSM models, it provides a somewhat different explanation as cited below.
Energy travels in waves but can change in form when subject to constructive or destructive interference. The primary wave types that experience this traveling wave interference are longitudinal and transverse waves that cause the electric and magnetic fields. The force of gravity is a result of lower longitudinal wave amplitude between particles as a result of a conservation of energy from spin. The strong force is a result of particles spinning at standing wave nodes, but in all cases, the motion of a particle is always toward a position of minimal displacement. i.e. wave amplitude, which is the cause of all forces.
This model has only been subject to a limited review, as per the link above, but the interested reader may use the following link: What is a Force? to review the details on the EWT website. However, the limited review has initially questioned many of the explanations forwarded by the EWT model, where the following description of charge is not really understood – see link What is Charge? or details.
Charge is traveling longitudinal wave energy. Mass and charge are related and can be simplified to a single energy equation. However, to relate mass and charge, the units of coulombs are explained as a wave amplitude measured in metres. If one assumes a substance in the vacuum of space has a physical property of kilograms, and moves as waves, then mass and charge can be described as their motion. In the EWT model, this substance is referred to as the aether and its components as granules, where mass is standing longitudinal wave energy and charge is traveling longitudinal wave energy over distance, i.e. a force.
While these wave models are not really the focus of this section of discussion, some reference will still be made to the Only Spacetime (OST) model, which has also only been subjected to limited review. However, the author of this model has produced a publication called The Universe is only Spacetime, where the following paraphrased extract is taken from page 4-21, such that it might provide an initial indication of the ideas being pursued.
It is claimed that there is only one fundamental force, which is repulsive. The obvious question is then: how can attractive forces such as gravity, the strong force or the electromagnetic force be the result of a single force that is only repulsive? By way of an initial explanation, the vacuum fluctuations have energy density equal to the Planck energy density. From the equivalence of energy density and pressure, it follows that vacuum fluctuations are capable of exerting a maximum pressure equal to Planck pressure of 10113N/m2. For example, a proton has a known radius of about 10-15m, where its volume combined with the proton’s energy implies that a proton has an energy density of about 1034J/m3. This energy density implies that the waves forming a proton generate an internal pressure of about 1034N/m2. Stated another way, an isolated proton is stabilized by the spacetime field exerting a repulsive force on all sides of the proton. If the proton comes near an electron, the proton experiences what we consider to be a force of electrostatic attraction. It will be shown that this is actually an unbalanced repulsive force. The vacuum pressure required to stabilize a proton is unbalanced by the distortion of the spacetime field caused by the electron’s electric field. This results in what appears to be a force of attraction. In this model there are no exchange particles that somehow achieve attraction. All action at a distance is ultimately traceable to a localized imbalance in the vacuum pressure. There are also no attractive forces. There is only an unbalanced repulsive force. i.e. an unbalanced pressure, exerted on fundamental particles by the dipole waves that are the vacuum fluctuations of the spacetime field.
While it is clear that possibly none of the wave models reviewed may be correct, they do, at least, try to forward a causal mechanism that might help explain how energy underpins all the fundamental forces. Whether this can be said for the overarching quantum field model might be questioned, if semantic descriptions appear vague and are overly dependent on mathematical abstraction. While this may appear to be biased opening assessment, we might use the following answer posted on a Q&A forum as an example.
Q:What is a quantum field and how does it interact with matter?
A:Quantum fields are a theoretical generalization of classical fields. The two classical fields are electromagnetic and gravitational fields. One way to think about the process of quantization is that we first reformulate the classical field equations using mathematical operators that replace some numerical, but then, we ‘solve’ the resulting operator-valued equations, including solutions that do not appear in the classical theory, and make the assertion that these solutions accurately describe Nature, including all the observed quantum behaviour that contradicts the classical theory. It is recognised that these solutions may appear ‘nonsensical’ to common intuition, but are considered to be a valid mathematical model of reality.
This statement is predicated on an assertion that the quantum model ‘accurately describes Nature’. While this review will question the accuracy of this assumption in terms of the issues to be discussed, it is not attempting to refute all the insights provided by this model, only the certainty of its scope. Within the broad remit of the quantum field model, quantum electrodynamics is considered to be one of the most fundamental elements of the particle interaction model, based on electrons and photons. As a generalization, QED is said to describe the dynamics of electrically charged particles interacting by means of an exchange of photons. Mathematically, QED is described in terms of the complexity of a perturbation theory within an electromagnetic quantum vacuum, however, given that this theory is an approximation method, we might question the implied certainty in the next quote.
In particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction.
Despite the certainty that ‘QED mathematically describes all phenomena involving electrically charged particles’, the reader is invited to search the internet for a causal description that provides an alternative to any of the wave models outlined. Usually, mainstream models will simply describe electric charge as a conserved property of a subatomic particle, e.g. electrons and protons, as though this is sufficient causal rationale of electromagnetic interaction. On this basis, descriptions proceed to explain that an electric charge may be positive or negative, or possibly neutral in its absence, where ‘like’ charges repel and ‘unlike’ charges attract. Of course, there are far more complex descriptions, as cited in the next quote, but it is unclear whether most readers will be any the wiser about causality.
A charge is any generator of a continuous symmetry of the physical system, where Noether's theorem implies the existence of a conserved current. The thing that ‘flows’ in the current is the ‘charge’, which is the generator of the local symmetry group and referred to as the Noether charge. The electric charge is the generator of the U(1) symmetry of electromagnetism, where the conserved current is the electric current. In the case of local, dynamical symmetries, associated with every charge is a gauge field and when quantized, the gauge field becomes a gauge boson, where a charge radiates a gauge field. The gauge field of electromagnetism is the electromagnetic field and the gauge boson is the photon.
While the interested reader might wish to follow the links in the description above, it is unclear that they will find anything that might be considered to be a causal mechanism that explains electric charge. Therefore, we might focus on the concept of ‘electric charge’ because it is an idea that has a relatively long history, which in many ways still rests on the assumption that charge, i.e. the coulomb, is a fundamental unit of measure and an attribute of a particle. Why this is so, might be explained in the following paraphrased quote.
The reason for this lack of progress is that QED has never been interested in causal mechanics, preferring to focus on probabilities. To explain the force between the electron and proton, the standard model now makes use of ‘messenger photons’ that act as force-carriers, which are then explained in terms of virtual particles. Such concepts allow the standard model to infer a force with no energy transfer, since the mediating particles are virtual, i.e. they have no mass equivalence, the energy and forces are also virtual.
So, by the use of virtual particles, the standard model attempts
to explain the concept of a force, and therefore physical motion, with
little reference to energy, such that
kinematics can proceed without causality. In 1900, physicist Lord Kelvin declared
that ‘there is nothing new to discover in physics, all that remains
is to more accurately measure its quantities ’ and, in many ways,
it appears that the quantum model may be repeating such hubris. However,
the nature of these discussions is not to propose solutions, simply to
highlight that issues still remain that require causal explanation,
which extend beyond mathematical abstraction.