Question:    With respect to what is space-time moving? If there is not something more fundamental than space-time with respect to which space-time, itself, is moving, then space-time cannot properly be said to move (or progress) at all.

Answer:    The term “space-time,” as used in the Reciprocal System of theory, is equivalent to, and interchangeable with, the term “motion,” in the broadest sense of the latter term, and the general nature of the answer to the foregoing question can readily be seen if the equivalent term is substituted for “space-time” in the wording of the question. No one appears to have any difficulty in recognizing that the end of a unit of time is later—more advanced—than the beginning of that unit; that is, there is a progression from the beginning to the end. Furthermore, it is commonly understood that this is simply a progression, not a progression relative to something else, and hence a unit of time, a section of the progression, is a self-contained entity. As the published expositions of the Reciprocal System have demonstrated, the concept of a universe of motion requires that space be defined in exactly the same terms as time, except that it is the inverse quantity. Thus the end of a unit of space is also more advanced—that is, more distant (the spatial equivalent of later)—than the beginning; not more distant from something but simply more advanced. Space, too, is a progression, and since both of its components progress, notion (space-time) is likewise a self-contained progression; it is not a “something” that progresses relative to something else.

Of course, a certain amount of mental effort is required in order to lift our thinking out of the grooves in which it has been running so long, but obviously if it is possible to conceive of time as a progression, independently of any hypothetical background—a mental feat that seems to present no particular difficulty—then it is also possible to conceive of an inverse quantity of exactly the same general nature. If there is any difficulty in so doing, it does not arise from the nature of the concept itself, but from an unwillingness, or inability, to let go of ideas that are derived from premises that have no relevance in a universe of motion. When space and time are viewed in terms of these concepts there should be no obstacle to recognizing that motion (or space-time) is a similar self-contained progression, According to the fundamental concept on which the new theoretical system is based, the unit of this progression—the unit of motion—is the basic entity of the universe, that from which all else is constructed. It cannot be related to anything “more fundamental.” The idea of a background to which motion must be related belongs to some concept such as that of a universe of matter; it has no place in a universe of motion, where motion itself is the ultimate reality.