Dear Zeeya Merali:
About your august 28 "Nature" article, which I wasn't able to read on the magazine, but I read that on it you discuss some of the theories, that are trying to explain the origins of space and time. I suppose this interest many people, But knowing that most physicists say, that while there is consensus on the mathematical significance of "space-time" in theoretical physics, for a hundred years there has been no consensus on the nature of "space-time" itself. I question myself, we shouldn't know first, or at least have consent of what is the "space-time" nature, before explaining its origins?
The paradox is that before explaining the origins of an actual "space-time" without consent about its "nature", I suppose we should research the "construction origin" in "space" and "time" with the hope of reaching a consensus about "space-time" nature, after we do that, I suppose it would be licit to ask ourselves about the detailed constitution of the construction and explain how it come to be: "its origins".
"Space" and "time" was called by Einstein pre-scientific concepts, of which mankind forgot its meanings, we should try to search as anthropologists with their origins.
Most of the first civilizations and cultures on earth in their languages, had the words that represents in those days concepts like "space" and "time". Then I think we should look for their origin, with the primitive men relation with nature, instead of given by known its "nature" and keep going to their detailed constitution origins with theories like: Gravity as thermodynamics, Loop quantum gravity, Causal sets, Causal dynamical triangulations, or Holography.
If we really want to know the "space" and "time" origin, from where they emerge, it seems basic to start with, how those words representing such primitive concepts born, and why they reach our days unharmed and indestructible, why didn't change. These were and are always, observation related with the same reality. "space", the only reality we can sense of it are their limits. "Space" itself can`t be sensed by any of our senses.
On the "The deep nature of reality" essay in the "It from Bit or Bit from It" FQXi contest, I made a demonstration based on centuries old proves, were I show that the "time empiric meaning" is "motion". I also show that "time itself" has not physical existence, just because consist in a measuring system of all kinds of "motions". With the celestial bodies or clock "constant, uniform and regular motions", that you can fraction in equal parts, that we should call "motion-units" as hours, minutes and seconds, with which comparatively we measure every "no constant, uniform change and transformation" of our choice, that were allowed by "motions", those are integrated in every physical existing thing". The truly "time problem" is that men are not conscious of the "system" and they just called all this system "time", That's why "time" I always say, just become a remnant word of this important pre-scientific measurement concept.
Forcing an emergence of "space" and "time", from not proved theories which did not become scientific yet, and taking into account, that when those concepts were originated, science as such did not exist as a reality, until many thousands and thousands years later, seems to me at least no convenient.
Considering everything we said, I think we should incline ourselves to an anthropic origin of those concepts, represented by "space" and "time" words. Anthropic in the restricted meaning of the word, meaning that without men observation, the words and specially the concepts represented by them, wouldn't exists as such, and as I think wouldn't have a comprehensible physical existence either, till revolutionary general relativity became a mostly proved physical reality with "space-time" construction.
"Space, time, and event, are free creations of human intelligence, tools of thought" Einstein, "Ideas and Opinions" IBN Nº 440-04150-150, pag. 354
On those old days, like today, most people use "space" and "place" indistinctly, in reference to the absences of solids and liquids, air and their gases CO2,N, O2 mostly did not count, at least till they didn't have wind strength.
"Place" seems a word, that means not only that can be occupied by a solid or a liquid, but also have the meaning of location. "Space" also can be occupied but without location meaning.
Like today most people from most cultures when they look to the stars they choose "space", immense, without limits, but still is used with earthly purposes too.
After science born, especially natural science, or physics later, "space" and "time", like many other knowledge, to become scientific, should be proved and there were the problems with "space" and "time" begun, nobody could.
After twenty five hundred years, more than a curiosity, for the first time it becomes necessary especially for theoretical physics. Now days is not enough to measure distances, or hours, we need to know if "space" and "time" are physical entities and if those have physical existence.
At first "space" was considered a distance, without anything in it, a vacuum, later on the vacuum existence, couldn't be proved in the laboratory and in space either, everywhere there was something.
So revolution came to science, and with general relativity it was use the Minkowski "space-time" construction in a theory, for the first time by Einstein who used as it was, inseparable in "space" and "time".
"Space" that mainly represented a vacuum, in GR becomes "the field" which represents everything, the complete universe. When "time" "motion" is added, that made it alive.
What I am going to say now will sound incredible. There is an Einstein "space-time" short verbal description, that I never read, quoted by any physicist, in no place. I can't believe that nobody could know better than him, the nature of "space-time" itself, the first physicist that used the construction in a theory. The only place where I read it, is in Einstein "Ideas and Opinions" page 365, ISBN - 440 04150 150. And he says "There is no such a thing as an empty space without field. Space-time does not claim existence on its own, but only as a structural quality of the field"....." "It requires the idea of the field as the representative of reality, in combination with the general principle of relativity".
It is said that in general relativity, "space-time" is assumed to be smooth and continuous, but an "structure", speaks of "parts" determinate composition, for the "field" at least when it is referred to the "space" part of the construction, planets, galaxies and subatomic particles, we can find many people that can agree with this, but when we put in place "time" to complete de construction, mathematically they had no problem, but not knowing what "time" means, seriously difficult to understand the "construction nature" we should say that as a separated part of the construction "time" it is not "structural" but instead it's the "motion" of the "space structure" which make "space-time" only "one thing" satisfying the inseparable condition of the construction.
Everywhere seems that not knowing the empiric "time" meaning, which is "motion" becomes and impediment, to continue forward in theoretical physics, they say, since the last fifty years.
"field-motion", which is "space-time" in Einstein words "reality in motion". I said in the essay, seems a gross description of everything. Certainly is not a "freeze universe" and let clear why can't be separated.
I think that knowing "time" empiric meaning, restrict so many different interpretations of the "space-time" nature.
When we know "time empiric meaning" is "motion" we can experimentally understand that a "speeding field part, as a clock" will slow its functioning, why? because of "inertia". Gravitational force also can do it. With those forces, what slows is not "time" but clock functioning (that's why Einstein always said that the clock slows, not "time" slows).
If we ask a physicist why an speeding clock will slow "time", if he knows the clock speed and light speed (c), they will show you the speeding clock "time dilation" but, instead if you ask him to explain to you, with simple words, experimentally, why "time" slows, what forces act on it to slow it, and even if he agreed with you that is not "time" but the clock what slows, and you ask him, why it slows?. What forces act on it, and slows it, I am afraid he wouldn't know. Why? because nobody would know how a force, of any kind would act on "time" Why? because nobody knows "time empiric meaning", so how you would explain a force acting over something you don't know what it is? which its physical characteristics are.
Nobody need to prove "inertia" and "gravity" existence, we experiment both every day. Of course it was mathematically proved, that speed and gravity slow "time", but experimentally it was impossible to understand how?
We understand this because "motion" is a "quality or property" of every physical existing thing, Instead if you do not know the "time" empiric meaning, that's why people have not a physic empiric explanation of why "time slows",
So these also explain "time dilation" or "relativistic time", "every clock" including atomic ones on those conditions slow its functioning "is not time that slows", but the clock.
The same phenomenon applied to the astronaut twin, because "inertia" molecules and atoms in his body metabolism would slow their "motion" living slowly, aging less than his brother on earth. It is not just the clock that works slower, but everything that speeds, would change and transform slower.
That's why in different parts of the "field" (space), gravitational force is different, so clocks would work at different speed functioning.
That is all about those paradoxes. Why? because we know that the empiric meaning of "time" is "motion".
When they are trying to quantized GR and come to a "the Wheeler-DeWitt equation" equation without a "time variable" resulting in a "freeze universe".
They are wrong, the "time variable" is there, "Changes" on the three spatial dimensions describing an event, also represent "motion", this is the supposedly "disappeared time variable, The problem is that it is not recognized as such. The fourth Ds. is an especial kind of "motion", constant, uniform, regular, "the clock" Einstein sometimes call it "imaginary".
May I said, that now we know a little more about "space-time", I suppose that maybe, this should make some difference on "Loop quantum theory" an "String theory" .I am also think if we would agree of what we said here, it could be reach a greater consent on the "nature" of "pace-time", and after that, just then, look for the constitution of the "field", It's origins.
Héctor D.Gianni
