Pruning the Multiverse
1. The Multiverse
At present, cosmological physicists propose an unruly welter of universes (despite the evident contradiction involved in using the plural of that noun).
Three types of coexistent universes are postulated:
1. In a spatially flat and infinite universe filled homogeneously and randomly with matter and subject to the limit speed of light, there must be an infinite number of “universes”, separated from each other by enormous distances and thus the lack of intersection of their light cones or event horizons. Here every possible universe based on the present local laws of physics should exist, including an infinite number of perfect replicas of this one.
2. If in the originating event of any universe the values and types of the fundamental constants are randomly distributed, every possible universe based on any combination of physical laws and constants would exist.
3. If every possible outcome of every quantum event is the case, and each outcome determines a different future universe, every possible permutation of every possible quantum event must be branching out at any moment from any universe based on quantum mechanics.
Time is usually described by such cosmologists as being not different in nature from space–for instance, our timeline is just a configuration of quantum universes whose connections are consistent with the laws of physics; we perceive that configuration as a sequence purely because of the biological limitations of our senses.
The multiverse, however, with its infinite dendrification, can perhaps be pruned in the light of both logical and physical considerations.
1. Let us define “the universe” as everything in existence at one time or another. Thus there cannot be “universes” because the word, like “everything” itself, is not usable in the plural. However, I shall adopt the plural form as used by cosmologists in order to demonstrate the logical flaws implied by such a usage.
2. Any perfect repeat of this universe, on the principle that a distinction that makes no difference is no distinction, is in fact this universe. We are all the identical versions of this universe there are. If hugely distant parts of this universe are identical in every way to this part, then those different parts of the universe are in fact this part; we would simply need to adjust our theory of the topology or multidimensional shape and embedding space of the cosmos so as to allow for various ways of returning to this part of the universe. Thus the universe, if there are “repeats” of its “wallpaper pattern”, turns out to be more like a compact knot–since all the repeats of all the other parts of the universe would be similarly the same part, reached by different paths, and thus there would be exactly one universe, made of all the possible configurations of matter, arranged in a space that would allow for all possible spatial orientations among them.
3. We can prune away all “universes”–or rather, parts of the universe–that are perfectly deterministic, since they would be describable without the use of the concept of time. The definition of “universe” includes time–i.e. a universe that does not last even one moment is no universe. A timeless universe cannot be; this is trivially true in physics, since all physical objects are vibratory in nature, and a vibration requires time to take place in. The definition of “deterministic” involves the requirement that the cause-effect relationship is perfect and unique, that is, the difference between logical inference and cause is eliminated. Every cause must perfectly imply its effect, and every effect must perfectly imply its cause. Logically cause and effect are reversible. But the distinction between space and time is that while space is reversible, time is irreversible–we can go from London to New York, and from New York to London; but though we can go from 1992 to 2004, we cannot go from 2004 to 1992. Thus in a perfectly deterministic universe there are no distinctions of before and after, only distinctions of logical priority and posteriority. A deterministic universe does not require time to be accurately and fully described. Thus a perfectly deterministic universe cannot exist. (The argument that time does not really exist except in the sensory systems of animals like ourselves is only germane to the argument if sensory systems, with their attendant world of temporal sequence, do not exist in the universe; and as we have seen, if they are not part of the universe they do not exist, which is a contradiction since sensory systems are what are writing and reading this.) A universe must be open-ended to be temporal and thus to have existence.
4. We can prune away all “universes” in which, at the other end of the scale from perfect determination, perfect randomness prevails. The reason is the same as in (3.). If the next event bears no relation to any previous event, there is no basis on which it can be asserted that there is any relation btween them, including that of time. Time includes in its definition some duration, even if it is only the “chronon” or minimum period of a vibratory entity. But duration implies some continuity between moments, and moments can be infinitesimally short. In a perfectly random universe, there could be no continuity among moments, and thus no time, and thus no universe. A universe must be minimally law-abiding to have existence.
5. We can prune away all “universes” which are purely probabilistic, and in which there are only quantum superpositions of possible events. A universe in which everything is possible is one in which nothing is actual. A real universe is one in which wave functions are collapsed, in which either ensembles of entangled virtual particles gradually actualize themselves through interactions in space and time until they cross the boundary between the quantum microcosm and the classical macrocosm, or already-actualized entities, their wave functions having been collapsed, act as the “observers” or informational termini that transform quantum probabilies into actualities.
6. One part of any definition of “universe” must be that it contains space, i. e. the possibility of separation and connection among its parts. A universe that is nowhere is no universe; a universe whose parts are nowhere is a universe that is nowhere. Being somewhere does not take much forcing: even as weak a spatial measure as the difference between entanglement and non-entanglement has been shown to be enough to create highly localized ensembles of particles. But the collapse from nonlocality into locality is always a unique historical event, which imposes further constraints on what kinds of universe could exist (see (8.)). In any case we can prune away all purely nonlocal universes.
7. We can prune away most of the content of the “parallel universes” that are thought to branch out from this one at every juncture where there is a random quantum event. The reason is simply that, lacking a means of instantaneous transport to some very distant place, those extra timelines, filled with matter, would remain here, and in aggregate would be so massive as to crush everything instantaneously into a huge black hole. If they were transported somewhere else, the energies required to accelerate them would be such as to destroy every piece of coherent matter by tidal and inertial forces. Obviously, too, the spontaneous creation of such huge amounts of matter and energy out of nothing would violate the fundamental conservation laws of physics, without which any physical reasoning would be impossible.
If new timelines do branch out from this one, their determinative weight would consist in each case of a single superposition of a single quantum event, which would need to fight the entire momentum of the rest of the universe to have any chance of initiating a new full-blown timeline in the universe of classical physics. Their fate would be like that of the random mutation in the genes of a living organism, that is almost always rapidly eliminated by natural selection. However, some of those deviations might survive locally in favorable circumstances, producing the characteristic fuzziness or wave-particle duality or nonlocality of objects at very small scales. Physicists have been able to create very small bunches of matter that exist in two places at once, thus preserving two timeline branches for observation. But such situations are extremely fragile and are easily erased by the crushing force of thoroughly actualized matter around them. Still, some such “ghosts” may exist in nature, and they may have accumulated in some quantities. The universe does, apparently, contain a good deal of massive “dark matter”, which may be in fact whatever timelines survive, by means of sequestration from most forms of physical interaction, the pressure to conform to the general consensual flow of things.
8. Given the limitations on initial conditions implied by (1.)-(7.), we can prune away any universe histories that require non-universe-producing beginning states (however coherent and law-abiding and open-ended such universes might be later on), or physics that would put a historical end to that universe before the present time. In all coherent physical science, a statement of the laws and constants must be supplemented by a statement of the unique historical situation, usually dismissed as “accidental” because not retrievable within the net of physical concepts being used, but indispensable if any prediction of experimental outcomes is to be made. Even physical constants and laws themselves–and the distinction between laws and constants begins to blur at the most fundamental level–may themselves have been the result of historical accidents and symmetry-breakings. Thus we can prune away any universe that does not contain specific initial conditions and a unique history consistent with its existence at any particular time.
What Is Left
What survives all this pruning?
Potentially a very big universe, but one with only one copy each of every possible configuration of matter, tied into an extremely complex topological knot. “Possible” here has several futher constraints. This universe must possess a perhaps unique set of physical laws and physical constants, so as to ensure the existence of time–that is, an almost paradoxical “saddle” of mixed randomness and determinativeness between two basins of total order and total disorder, neither of which crosses the threshold into a time regime within which vibratory entities are possible. The renormalized universe must contain actualities as well as virtualities, localities as well as nonlocalities. It must have a way of disciplining local branchings of superpositions to avoid too great an accumulation of different material timelines in one place. Its possible configurations of matter must be consistent with its initial conditions and history of accidents.
What we have left may very well be just this “one” universe, with its penumbra of virtual particles, its microstructure of quantum foam, and its hidden load of dark matter consisting of timelines that are only weakly–through gravitation–connected to the main line of the universe’s history. It is an open-ended universe, with plenty of wiggle room between the determined and the random for self-organizing entities such as complex cyclic chemistry, plants, animals, and human beings to take their place in helping determine the future.