Ghetalion said:
Talk about not knowing enough on the topic! But it fascinates me to no end...
I've read that, according to Lee Smolin, there are discrete units of space and that there is mathematical support that upon dividing this space, it creates another unit of space of equal "volume".
Furthermore, if there is discrete parts of space, then they must contain systemic properties (direct or indirect) of their own. (depending on what you are using to explain these bits of void)
Would it be possible to entangle two (or more) units of space so that their causality networks (for lack of a better term... the "thing" that determines that void bit A is connected to void bit B so all matter passage from A will go to B) would be identical but inverted? Or is proximity alone enough to describe the causal connections between void bit A and B?
Basically: causality between two quantum bits of space... is it theoretically possible to reassign it via entanglement or another similar process?
So, going back to the OP, I can't speak for Smolin, but I have had similar thoughts on my own.
Ghetalion said:
"I've read that, according to Lee Smolin, there are discrete units of space and that there is mathematical support that upon dividing this space, it creates another unit of space of equal "volume"."
If there is a smallest space (that is, a discrete unit), and you divide it, then the quotient is once again the smallest space. Since the smallest space must be equal to the smallest space, there you have it. There can be no smaller volume. No matter how many times you divide the smallest volume, it is still the smallest volume. This is the same result as dividing zero by any number in math, or the same as saying it requires infinite energy to divide the smallest space.
Really, in physics now intead of philosophy or math, there is a more practical limit on how small a space we can divide. Dividing a small space is equivalent to inserting a wave into that space. We know that waves confined to small spaces are more energetic than waves in large spaces. This means that to divide a smaller space, we need a more energetic wave. But we only have so much energy available to us. Even if we could convert all of the energy of the observable universe into dividing one small space, that space would still have a definite size greater than zero.
There is still one more way to see this. I don't know if it is mathematics, physics, or general philosophy. Start by imagining an entirely empty universe, no boundaries, no interior structure of any kind. Now mentally insert a single fundamental unitary object...how big is it? It has no internal structure. There is nothing outside of it to compare it to. How big is it? Do not be surprised if you cannot find a reasonable answer. Now divide this object any way you wish. Is there any way, consistant with the universe we have just created, to compare the parts of the divided object? Are they close together or far apart? Are they equal in size or different? Is there any way to uniquely name the parts as individuals?
I suggest from the above logic that there is no way to evolve complexity from uncontained emptyness.
How then is complexity obtained?
It would seem that complexity requires a bounded universe (call it a background if you wish) containing two or more fundamental, comparable, inequivalent objects. It seems to me now that there is no other way to construct a basis. Without these conditions we cannot talk meaningfully about size, location, motion, or any of the other physical quantities.
Ghetalion said:
"Furthermore, if there is discrete parts of space, then they must contain systemic properties (direct or indirect) of their own. (depending on what you are using to explain these bits of void)
Would it be possible to entangle two (or more) units of space so that their causality networks (for lack of a better term... the "thing" that determines that void bit A is connected to void bit B so all matter passage from A will go to B) would be identical but inverted? Or is proximity alone enough to describe the causal connections between void bit A and B?
"
I am not sure how you came to the conclusion that discrete parts of space must contain systemic properites of their own, nor how these supposed properties would differ directly or indirectly. Of course if you are imagining discrete parts as pieces of a larger structure, what you say would have to be true. In physics, we can crush salt into smaller and smaller bits, each of which has the structure of salt, until we come to a certain limit. Anything smaller than the size imposed by that limit is not salt.
Objects smaller than the limit have new properties of their own which we can investigate. Sodium and Chlorine are atoms which make up salt. If we reduce the limit further we find sub-atomic and then sub-nuclear particles. Protons and neutrons have internal parts, called quarks and gluons. The standard model of particle physics lists the most fundamental known objects. There is some speculation that quarks may be made of preons or axions or some other more fundamental bits. However we have now passed beyond the limit of energy available to our technology. We have no current means to physically define discrete objects smaller than that.
But these limts are still actually rather large. A proton is about 10^-9 cm. It has three quarks. Each quark then would occupy about a third of the volume of the proton. Compare this to the size of the Planck length, the smallest theoretical length in physics, at 10^-33 cm. You must realize that this is an exponential scale...the Planck length is as much smaller than the proton as you and I are smaller than the known universe. The Planck length was determined by calculating the size of the space a proton mass would have to be compressed into to turn it into a Schwartzchilde singularity, or black hole.
If you have followed this logic of scale, you will see that matter in the forms we know it cannot be thought of as inhabiting a fundamental unit of discrete space. In fact, the smallest units of matter we know would have to occupy billions upon billions of discrete fundamental units of space.
The questions of interest on this board have to do with the geometry such fundamental discrete units of space would have to obey in order to produce the large statistical effects we know as phenomenology. How can we account for the behaviors of matter such as mass, electomagnetics, the weak force which holds nucleons together, the strong force responsible for quark confinement into nucleons?
Returning to the top of this liturgy, space and time are equivalent, and at the Planck scale, in fact, anywhere below the Fermi scale, it will not do to consider one without the other. This is why it is better to think in terms of action rather than of spatial continuity or temporal flux alone. An electron emits a photon. This action occupies both space and time in some measurable quantities. The photon has a length and a velocity. The electron occupies a position and has a momentum. You would think we could pin everything down quite nicely with this information. But HUP and SR throw in some wrenches. Quantum effects at measurable scales are counterintuitive. Time and space are not well-behaved. They stretch and compact and require topological logic instead of rulers and clocks.
Actually, causality itself is under siege. I have become suspicious that causality will have to be relegated to a secondary effect...dependent on the state of the observer, and not a thing in itself. Sure, we all agree that A causes B, but that may only be because we are all in roughly the same region of space and all headed roughly in the same direction at roughly the same velocity. We are free to imagine contrarian observers, for whom B causes A, or other observers for whom B and A have no logical connection whatever.
Fortunately we are saved from total confusion by the practical fact that we cannot discuss A, B, or C with such observers. They would be outside of our light cone.
Now I intend to occupy what time remains to me in considering the possibility that somewhere below the Fermi scale, where quantum effects predominate, there is a measurable region in which the light cones all must interact. If so, then there is a very small, very short, but ubiquitous region in which we do communicate with our banished other selves. I suspect that in these regions there are only a few possible alternatives, maybe a handful, but not the infinity of multiverses that so disturb the economists among us. I think we shall find, not far beyond our current limits, a fundamental space-time structure in which there are perhaps two or three alternative optional universes, probably not more than eight from any juncture.
Happy New Year.
Richard T. Harbaugh
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