Matter is substance and so is light (see ** The Logic of Substance**). A substance has substantiality. The measure of substantiality is given by mass concentration. We may use the word “substantiality” to mean mass concentration.

**By substantiality we mean mass concentration.**

As shown in the chapter on * The Logic of Field*, the range of substantiality (mass concentration) was extended greatly with the discovery of the nuclear and electronic regions in the atom. The substantiality of nucleus is greater than the substantiality of matter. The substantiality of electron, on the other hand, is many orders of magnitude less than the substantiality of matter.

We apply the term “mass” to matter, but when we consider particles like protons, neutrons and electrons, we assume the mass to be distributed throughout the volume of the particle. Hence, we are dealing with mass concentration, or substantiality, at a location in space. We may, therefore, conclude:

**A location in space has substantiality.**

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**Substantiality and Energy**

Einstein’s famous
equation, **E = mc ^{2}** shows the equivalence of mass and energy. It
also shows that infinitesimal amount of mass is equivalent to a significant
amount of energy because of the large multiplier

**c**. Therefore, an infinitesimal amount of mass may only be detectable as energy.

^{2}The mass of the electron field may be back calculated as **E/c ^{2}**, but it is so small a number that physics uses the equivalent energy value. to represent the substantiality of the electron field.

The presentation of substantiality of field in energy units has, unfortunately, contributed to conflating the traditional concepts of mass and energy. The energy units do not imply that field has no substance.

**The substantiality is expressed in mass units, but, for fields, it may be expressed in energy units.**

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**Intrinsic Motion**

The agitation of gas molecules is an example of intrinsic motion. Another example is the Brownian motion. These particles move by themselves. There are no external forces acting on these particles. Another example of intrinsic motion is the rapid motion of electron field around the nucleus.

The intrinsic motion of a substance exists because of its intrinsic nature. Therefore, the intrinsic motion must depend on substantiality. We may say that the rapid motion of electron field around the nucleus exists because of the large substantiality differential between these two regions within the atom.

The intrinsic motion of light expresses itself as the speed of light. Therefore, the speed of light is also an expression of the substantiality of light.

**Substance has intrinsic motion that depends on substantiality.**

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**Speed** & Mass Concentration

The more substantial is the substance the greater is its endurance, the longer it stays in a state, and the slower is its rate of intrinsic change. This is the case with solid matter. On the other hand, the less substantial is the substance, the lesser is its endurance, the shorter it stays in a state, and the faster is its rate of intrinsic change. The is the case with ephemeral light. Therefore

**The rate of intrinsic change is inversely proportional to substantiality.**

The rate of intrinsic change for light appears to be its motion in space. This motion is absolute because it does not depend on anything external to light for its existence or specific nature. From this perspective, the absolute motion of matter is close to zero because its rate of intrinsic change in space is extremely slow. Therefore

**The rate of intrinsic change appears as absolute motion in space. **

The absolute motion is very different from relative motions of objects. The speed of light is 3 x 10^{8} meters/sec. This is a measure of absolute motion. The orbital speed of earth around the sun is about 3 x 10^{4} meters/sec. This is a measure of relative motion. We cannot say that the speed of earth is 1/10,000 of the speed of light because this is not comparing the same type of motion. The absolute motion of earth is very likely even a smaller percentage of the speed of light.

**We cannot compare relative speeds to the speed of light.**

The speeds of material bodies and fields may only be compared in terms of their substantiality (mass concentration). This comparison is anticipated by the mass-energy equivalence. As the intrinsic mass is replaced by an equivalent amount of intrinsic energy, it has the effect of increasing the intrinsic motion of the substance. This may be demonstrated by the following sketch.

This leads to the conclusion that,

**The intrinsic speed of substance is inversely proportional to its mass concentration.**

The substantiality of electromagnetic field (EMF) is much less than the substantiality of the electronic region in the atom. Therefore, the EM field moves much more rapidly compared to the electron field.

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**Additional Conclusions**

We may expect a material body to be fixed in its natural velocity in space. If it is forced to accelerate by the application of external force, it will return to its natural velocity when that force is removed. It will not continue to move at its accelerated velocity forever. This conclusion modifies what Newton proposed.

If a material object is
continually accelerated by the application of a constant force (as in a
gravitational field), then its substantiality decreases with acceleration. This
change, however, may be imperceptible because of energy to mass ratio is **c ^{2}**

**to 1**.

Any substance at absolute rest must have infinite substantiality. Therefore, the substantiality of postulated stationary aether shall be infinite. We do not experience space being filled with a substance of infinite substantiality. Therefore, Einstein was correct in discarding the notion of stationary aether.

The substantiality of the EM field may be approximated by its frequency. Higher frequency would mean higher substantiality. We may, therefore, expect the velocity of the field substance to slightly decrease with increasing frequency.

The velocity of light is generally measured at the frequency of visible light. We assume on the basis of Maxwell’s theory that this velocity is the same throughout the EM spectrum. Maxwell’s theory assumes an aether of uniform substantiality as the medium throughout the EM spectrum. That may not be so.

The gravitational field is expected to have a substantiality much less than that of the EM Field. Therefore, the velocity of the gravitational field is expected to be higher than the velocity of light

**Implications of the
above on the special theory of relativity shall be covered later.**

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