In order to avoid the “heat death” of eternal cyclic model, it is postulated that the universe expands with each cycle. However then, by the Borde-Guth-Vilenkin incompleteness theorem, this means that the eternal cyclic universe cannot be past-eternal.
Like the eternal inflationary model, the eternal cyclic model may be eternal in the future, but it cannot be eternal in the past.
Therefore, any eternal cyclic multiverse must have begun to exist.
The assumption of an eternal cyclic multiverse only pushes back the beginning of our universe.
Our universe, therefore, must have begun to exist.
Emergent cosmic egg model
In this model, the universe originated from a “cosmic egg” that existed forever until it breaks open to produce an expanding universe.
Since the “cosmic egg” is initially static and not expanding, the Borde-Guth-Vilenkin incompleteness theorem is not violated.
However, Mithani and Vilenkin prove that the emergent cosmic egg model collapses quantum mechanically and cannot, therefore, be past-eternal.[2]
Ockham’s Razor redundancy
Ockham’s Razor is a philosophical principle that “plurality should not be posited without necessity.” Therefore, it gives precedence to the simpler more comprehensive explanation in order “entities are not to be multiplied beyond necessity.”
By Ockham’s Razor, the simplest most comprehensive explanation remains the one universe model because the cause of the “first” universe would remain whatever the number of the universes, but the idea of more than one universe raises more questions, as we have seen above. Multiple universes are examples of “entities…multiplied beyond necessity.”
It is not necessary to explain the origins of our universe by postulating the existence of a multiverse. Therefore, the accelerating inflationary big bang model remains the best explanation for the origin of our universe.
The universe has an external cause
Since it is true:
- that everything that begins to exist has an external cause
- that the universe began to exist
it is true that the universe has an external cause.
Let’s call this external cause, God.