Just to make it more complicated again ....
Pincho Paxton said:
But time travel is more like shortening distances from one place to the next.
When I read that, naturally I think of the tesseract in
A Wrinkle in Time.
I don't want to take the thread into pseudo-science, even though it is already pseudo-science.
Well, time is affected by gravity. But even that is insufficient.
At its core, the metaphysical answer is that time is a requisite of change:
The Qabalists expanded this idea of Nothing, and got a second kind of Nothing which they called "Ain Soph"-"Without Limit". (This idea seems not unlike that of Space.) They then decided that in order to interpret this mere absence of any means of definition, it was necessary to postulate the Ain Soph Aur-"Limitless Light". By this they seem to have meant very much what the late Victorian men of science meant, or thought that they meant, by the Luminiferous Ether. (The Space-Time Continuum?) All this is evidently without form and void; these are abstract conditions, not positive ideas.
The next step must be the idea of Position. One must formulate this thesis: If there is anything except Nothing, it must exist within this Boundless Light; within this Space; within this inconceivable Nothingness, which cannot exist as Nothing-ness, but has to be conceived of as a Nothingness composed of the annihilation of two imaginary opposites. Thus appears The Point, which has "neither parts nor magnitude, but only position".
But position does not mean anything at all unless there is something else, some other position with which it can be compared. One has to describe it. The only way to do this is to have another Point, and that means that one must invent the number Two, making possible The Line.
But this Line does not really mean very much, because there is yet no measure of length. The limit of knowledge at this stage is that there are two things, in order to be able to talk about them at all. But one cannot say that they are near each other, or that they are far apart; one can only say that they are distant. In order to discriminate between them at all, there must be a third thing. We must have another point. One must invent The Surface; one must invent The Triangle. In doing this, incidentally, appears the whole of Plane Geometry. One can now say, "A is nearer to B than A is to C".
But, so far, there is no substance in any of these ideas. In fact there are no ideas at all) except the idea of distance and perhaps the idea of between-ness, and of Angular Measurement; so that plane Geometry, which now exists in theory, is after all completely inchoate and incoherent.. There has been no approach at all to the conception of a really existing thing. No more has been done than to niake definitions, all in a purely ideal and imaginary world.
Now then comes The Abyss. One cannot go any further into the ideal. The next step must be the Actual --- at least, an approach to the Actual. There are three points, but there is no idea of where any one of them. is. A fourth point is essential, and this formulates the idea of matter. The Point, the Line, the Plane. The fourth point, unless it should happen to lie in the plane, gives The Solid. If one wants to know the position of any point, one must define it by the use of three co-ordinate axes. It is so many feet from the North wall, and so many feet from the East wall, and so many feet from tbe floor.
Thus there has been developed from Nothingness a Something which can be said to exist. One has arrived at the idea of Matter. But this existence is exceedingly tenuous, for the only property of any given point is its position in relation to certain other points; no change is possible; nothing can happen. One is therefore compelled, in the analysis of known Reality, to postulate a fifth positive idea, which is that of Motion.
This implies the idea of Time, for only through Motion, and in Time, can any event happen. Without this change and sequence, nothing can be the object of sense. (It is to be noticed that this No. 5 is the number of the letter He' in the Hebrew alphabet. This is the letter traditionally consecrated to the Great Mother. It is the womb in which the Great Father, who is represented by the letter Yod which is pictorially the representation of an ultimate Point, moves and begets active existence) ....
(Crowley)
Liber LXXVIII is Aleister Crowley's exploration of the tarot, and this context should always be remembered; it is
metaphysical, despite Crowley's self-aggrandizing outlook.
But it points to something that
science might—perhaps
ought to—be able to explain, which is the necessary relationship between time and change. And that is where things like the Cesium Clock come in. One can reasonably propose that there is something more fundamental by which we might measure time than a cesium atom. And I have great faith that science will figure it out. At some point, it is fair to say that there are two limitations to science according to humanity: Our ability to measure, and our ability to contain and manipulate data. It is my general
belief, for instance, that there are more factors to account for in discovering the fundamental truth of the Universe than the finite human brain is capable of containing and manipulating.
(Reversing this consideration toward metaphysics, it is the reason why no human being can perceive and comprehend "God". A cosmic-scale "TMI", if I might be permitted a sad
cliché.)
Fundamentally, though, understanding time requires us to identify and comprehend the most basic devices of change in the Universe. To wit, and perhaps just for a mindflog, any event you perceive in real-time is actually
history by the time you recognize it. That is, the event you perceive has already occurred. This appears to be absolute. Whatever signal you perceive is
not simultaneous; the light that reaches your eyes has traveled for a period; the sound that reaches you has traveled for a period; the thoughts that occur in your mind are processed after the fact. Even with something like a car-bomb going off in your proximity, whatever you perceive is already over. Since I'm delving in metaphysics and philosophy, then, I'll simply make the joke that
history kills.
The bottom line is that metaphysically I understand time as a fundamental component of change; that time is subject to gravity; and that basic atomic functions (e.g., cesium oscillation) are the most accurate means we have to measure time. Whether this means science has discovered a fundamental (unchanging, if you want an ironic phrasing) definition of time is not known to me, though I have great faith that this particular answer is well within humanity's faculties.
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Notes:
Crowley, Aleister. The Book of Thoth: A Short Essay on the Tarot of the Egyptians (Liber LXXVIII). 1944. BibliotecaPleyades.net. October 15, 2011. http://www.bibliotecapleyades.net/crowley/libro_thoth.htm