Reference: http://www.relativitybook.com/resources/Einstein_space.html

__NOTE: Einstein’s statements are in italics. My understanding follows in bold.__

*“What is the position of the special theory of relativity in regard to the problem of space? In the first place we must guard against the opinion that the four-dimensionality of reality has been newly introduced for the first time by this theory. Even in classical physics the event is localised by four numbers, three spatial co-ordinates and a time co-ordinate; the totality of physical “events” is thus thought of as being embedded in a four-dimensional continuous manifold. But on the basis of classical mechanics this four-dimensional continuum breaks up objectively into the one-dimensional time and into three-dimensional spatial sections, only the latter of which contain simultaneous events. This resolution is the same for all inertial systems. The simultaneity of two definite events with reference to one inertial system involves the simultaneity of these events in reference to all inertial systems. This is what is meant when we say that the time of classical mechanics is absolute. According to the special theory of relativity it is otherwise.*

*“The sum total of events which are simultaneous with a selected event exist, it is true, in relation to a particular inertial system, but no longer independently of the choice of the inertial system. The four-dimensional continuum is now no longer resolvable objectively into sections, all of which contain simultaneous events; “now” loses for the spatiaIly extended world its objective meaning. It is because of this that space and time must be regarded as a four-dimensional continuum that is objectively unresolvable, if it is desired to express the purport of objective relations without unnecessary conventional arbitrariness.*

*“Since the special theory of relativity revealed the physical equivalence of all inertial systems, it proved the untenability of the hypothesis of an aether at rest. It was therefore necessary to renounce the idea that the electromagnetic field is to be regarded as a state of a material carrier. The field thus becomes an irreducible element of physical description, irreducible in the same sense as the concept of matter in the theory of Newton.*

*“Up to now we have directed our attention to finding in what respect the concepts of space and time were modified by the special theory of relativity. Let us now focus our attention on those elements which this theory has taken over from classical mechanics. Here also, natural laws claim validity only when an inertial system is taken as the basis of space-time description. The principle of inertia and the principle of the constancy of the velocity of light are valid only with respect to an inertial system. The field-laws also can claim to have a meaning and validity only in regard to inertial systems.*

*“Thus, as in classical mechanics, space is here also an independent component in the representation of physical reality. If we imagine matter and field to be removed, inertial-space or, more accurately, this space together with the associated time remains behind. The four-dimensional structure (Minkowski-space) is thought of as being the carrier of matter and of the field. Inertial spaces, with their associated times, are only privileged four-dimensional co-ordinate systems, that are linked together by the linear Lorentz transformations. Since there exist in this four-dimensional structure no longer any sections which represent “now” objectively, the concepts of happening and becoming are indeed not completely suspended, but yet complicated. It appears therefore more natural to think of physical reality as a four-dimensional existence, instead of, as hitherto, the evolution of a three-dimensional existence.*

*“This rigid four-dimensional space of the special theory of relativity is to some extent a four-dimensional analogue of H. A. Lorentz’s rigid three-dimensional aether. For this theory also the following statement is valid: The description of physical states postulates space as being initially given and as existing independently. Thus even this theory does not dispel Descartes’ uneasiness concerning the independent, or indeed, the a priori existence of “empty space”. The real aim of the elementary discussion given here is to show to what extent these doubts are overcome by the general theory of relativity.” ~ Albert Einstein*

*.*

**Time was held absolute in classical mechanics, but it is no longer so in the special theory of relativity. But “space-time” was still being held absolute and independent with respect to matter.**

**The electromagnetic field could no longer be regarded as a state of a material carrier, such as, aether at rest. The field thus becomes an irreducible element of physical description. **

**Concept of motion arises as the “evolution” of three-dimensional space with respect to absolute time. But when existence is looked upon as four-dimensional space-time with respect to absolute matter, how does it “evolve”?**

**The Disturbance Theory regards that field (energy) and matter arise as the “evolution” of four-dimensional space-time.**

**The Disturbance Theory looks at Space-Energy-Matter as three states of INERTIA, just like Classical Mechanics looks at gas-liquid-solid as the three states of matter.**

**Time seems to appear as the continuously varying parameter underlying the spectrum of “space-energy-matter”.**

*Previous: **Relativity and the Problem of Space (Part 10)*

*Next: * *Relativity and the Problem of Space (Part 12)*

.