A Hypothesis of Circular Causality
Let us speculate freely a bit on the nature of Nature. The basis of the "time-loop" hypothesis I propose in this essay is a relatively new perspective in quantum theory put forth by physicist John Cramer. While not universally accepted, his approach has enjoyed some success in scientific circles. In short, Cramer's Transactional Interpretation of quantum physics states that at such a time as the wave function of a given quantum mechanical object such as a subatomic particle 'collapses' due to its having assumed a definite state, that particle emits an 'advanced wave' which travels backward in time to the instant of the particle's creation and determines its future course. The present, then, is determined not only by the past, but by the future as well.
If we consider the Universe as a whole to be a quantum mechanical object with its own wave function (as some physicists do), it becomes possible to imagine that at such time as the Universe reaches a final state (either of 'heat death' through thermodynamic equilibrium or singularity through a 'big crunch'), its wave function will collapse and an advanced wave encompassing the entire 'worldline' or history of the universe as a whole will be travel backward in time to the instant of the first quantum fluctuation which triggered inflation, causing the creation of the Universe and determining its course.
Here we encounter the most startling implications of the 'backward' causality inherent to the Transactional Interpretation. If the end of the universe will be the cause of its creation, we see that all existence is a 'time loop' of sorts. We now have 'circular causality' - the beginning of the universe leads to its end, which leads to its beginning, and so on, ad infinitum. Dizzying, perhaps, but not contrary to quantum mechanics.
A moment's thought will lead to some rather bizarre implications. Firstly, each of our lives will repeat (and has repeated) infinitely. After death, one can envision an incredibly long period of which we will have no consciousness during which the second law of thermodynamics will lead to final collapse of the Universe's wave function, then a (relatively) shorter period of non-existence after the creation of the Universe (which was caused by its end). Then we will be born. The next thing we will know after death is our own birth. This is not really 'another' birth in any meaningful sense, but much more accurately our original birth, which is a mind-twisting idea that lends an entirely new perspective to the feeling of 'deja vu' that we all experience from time to time.
The picture becomes even more bizarre when we add Andrei Linde's self-replicating inflationary theory to the mix. Linde suggests that each universe which undergoes inflation (a 'Big Bang') has within itself the capacity to trigger new inflations, resulting in a never-ending chain of universes budding off from their predecessors. Since this larger, 'mulitiversal' sequence will never end, it cannot have a beginning, according to the Transactional Interpretation, since there would be no definite final state from which an advanced wave could travel backward to determine the future course of creation.
Therefore, we have not only a universe which is infinitely circular, we have an infinite number of such universes. Not only does everything possible exist, it exists eternally.
This is very difficult to envision due to our experiential bias toward linear causality through forward time, which (according to the Transactional Interpretation) is an imcomplete understanding of events on the quantum level. In reality, the Schroedinger equation, foundation of quantum mechanics, has solutions not only in forward time but in 'backward' time as well. If one wonders how a universe can both be caused by itself and yet be dependent on a predecessor universe for its existence, it must be remembered that the predecessor universe itself would experience circular causality, allowing it to spawn the inflation of the new universe repeatedly, in an infinite loop. Rather than picturing the sequence of universes expanding over time, it is more useful to picture the sequence as eternally infinite, since time itself is a property only of the laws of physics operating in each individual universe. There are an infinite number of universes creating themselves an infinite number of times over - a logical conclusion if one is trying to envision the greatest reality imaginable. If my speculations are anywhere near accurate (which is of course debatable), we may have glimpsed the 'Omniverse,' an endless interconnected whole that is beyond imagination in its scope.
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