# Is a cyclical model of time and the universe logically valid, and which philosophers (if any) have proposed such a model?

If we accept the following premises:

1: An event (such as a Big Bang) happened. (I use the phrase Big Bang, because many are familiar with that as the "Initial Cause", but this theory would necessarily utilize a different understanding in that regard) 2: Every event necessarily causes some other event 3: Identical events yield identical causes

Is it logically valid to state that an event (A), such as the Big Bang, necessarily caused events B, C, D... and necessarily caused the conditions (events) extant at this very point in time- And that said series of events could eventually lead to an event (and associated conditions) necessary for the event which caused the initial event (A) (such as the Big Bang). Thus this event (A1) will be identical to the earlier event (A), and thus yield an identical series of causes and events, necessarily causing another identical event (A2). So on.. so on...

Issues of fundamental physics aside, is the above valid? My question stems from the fact that this seems like a very appealing and intuitive model of existence, but I have not seen it discussed in any of my classes. I assume that may be due to some obvious problem with the logic that I am missing.

Also, if anyone knows of a good text to deal with the question, I would love to read it.

Nietsche held this view. As a materialist with an assumption of Newtonian physics, and without the notion of chaotic strange attractors, which would not come along for quite some time, you are kind of stuck with it. Newton's time and space are infinite, so either things endlessly converge on a boring ending, or they eventually all align in the same state as one they occupied previously, and therefore endlessly loop.

Most folks found the latter conclusion too weird, and supposed 'death in fire or in ice'. But this option seems more likely statistically -- things would either actually repeat, or converge so close that the difference could no longer matter.

It emphasized for Nietsche that infinities and idealizations really do not remove the urgency of single acts, because time may be infinite, but freedom is still finite. The world may not end, but it might as well, as far as moral decisions go. We need to whip humanity into shape 'this time around'.

However, issues of elementary physics cannot be put aside -- Our physics has changed. We now assume premise (3) is flawed: quantum mechanics requires that actual outcomes in particle interactions are necessarily random to a certain degree, and not totally determined by the properties and internal state of the particles themselves.

Nor can modern mathematics -- Strange attractors do exist, continuous behavior can devolve into discontinuous chaos and lose all convergent qualities. So there could be causal threads that necessarily have different states at the end of each cycle and bleed into the next, without ever converging, no matter how long the cycle plays itself out.

(I guess I did not answer the first part of the question. If mathematics is all part of logic, then no, by this last observation, the OP is no longer logically valid. It is at least no longer reasonable to assert it as necessary or likely, because chaotic behavior is ubiquitous.

If advanced mathematics at some point becomes something beyond a part of logic, you need a whole theory about what mathematics is, in order to decide your answer.)

1. Is a cyclical cosmology logically valid in principle?

Yes.

1. Is a cyclical cosmology physically valid in principle?

Yes, as there are several physically plausible ways whereby a contracting universe would not contract to a singularity but would bounce and start to expand, so that a "Big Bang" could actually be a "Big Bounce" from a "Big Crunch".

Such a bouncing cosmology is seriously offered by a small minority of scientists as an alternative to mainstream inflationary cosmology [1].

1. Is a cyclical cosmology physically valid in practice?

No, because it is inconsistent with the conclusively established finding that the expansion of the universe has been accelerating during the second half of its history [2] [3].

Taking into account this finding, anyone postulating a cyclic cosmology must necessarily also postulate:

• either that some presently unknown mechanism will change the currently accelerating expansion into decelerating expansion, stop, and then contraction,

• or that something changed between all previous instances of the universe and the current instance, whereby all previous instances decelerated their expansion and reversed into contraction whereas the current instance will expand for ever.

Either postulate can be described with just two words: fanciful thinking.

References

[1] Anna Ijjas, Paul J. Steinhardt, and Abraham Loeb, Cosmic Inflation Theory Faces Challenges, Scientific American February 2017. https://www.scientificamerican.com/article/cosmic-inflation-theory-faces-challenges/

[2] David Rubin and Brian Hayden, Is the expansion of the universe accelerating? All signs point to yes, The Astrophysical Journal Letters, Volume 833, Number 2 (2016). https://arxiv.org/abs/1610.08972

[3] Balakrishna S. Haridasu, Vladimir V. Luković, Rocco D’Agostino and Nicola Vittorio, Strong evidence for an accelerating universe, Astronomy & Astrophysics, Volume 600, L1 (2017). https://arxiv.org/abs/1702.08244

• Roger Penrose proposed CCC, a conformal cyclic cosmology, and in 2010 published a popular book about it, 'Cycles of Time'. Jan 20, 2018 at 22:01
• See these CCC reviews: preposterousuniverse.com/blog/2010/12/07/… and forbes.com/sites/briankoberlein/2015/12/12/… Both reviews note that mathematically mapping the smooth late stage of this universe (10^100 years from now!) onto the smooth early stage of the next universe does not mean that there's any physical process that could actually cause that to happen. "What causes the low-density late universe to come alive into something like the high-density early universe?" Jan 20, 2018 at 23:59

Hindu scriptures hold that the universe is eternally without beginning and without end, a series of cycles. The present universe is one such cycle. After a period of time, the universe falls back to a potential state of quiescence and then after some time is projected out again. There is no creation in Hinduism, the literal word used is projection. The question is whether previous and subsequent universes have the same physical laws or different. The other thing to contemplate is that when rolling dice, the same combination of rolls will sooner or later repeat themselves. Given an infinite number of universes in infinite time, our universe and all of us and all our experiences will sooner or later exactly repeat themselves........

• That last line is what I find to be a particularly interesting point. Not only will the exact same sequences repeat themselves, according to that understanding, but they will do so infinite times. And if physical space is set to infinity or near infinity- They are right now!
– Dog
Oct 11, 2014 at 14:01
• Yes, it says in the Brahmavaivarta: "But the universes side by side at any given moment...who will estimate the number of these? Beyond the farthest vision, crowding outer space, the universes come and go, an innumerable host. Like delicate boats they float on the fathomless, pure waters that form the body of Vishnu [Brahman]. Out of every hair-pore of that body a universe bubbles and breaks. Will you presume to count them?" Oct 11, 2014 at 14:47
• This sounds great. Is there an online source? Oct 14, 2014 at 14:07
• Also do the Hindu scriptures specifically state that universes must sooner or later reoccur in exactly the same way? Or is this a later, modernist extrapolation? Oct 14, 2014 at 14:08
• 1) No online source I am aware of. 2) This was I believe a later extrapolation by Swami Vivekananda (1863-1902). the extrapolation is in his Complete Works under the heading Juana Yoga (online available). Oct 14, 2014 at 14:51