The Universe expanded from a singular mathematical nothing-point, literally called a singularity.
On this page we can explore four arguments:
This is relevant because,
“At this singularity, space and time came into existence; literally nothing existed before the singularity, so, if the Universe originated at such a singularity, we would truly have a creation ex nihilo” [J. Barrow and F. Tipler, The Anthropic Cosmological Principle (Oxford, 1986), 442.]1
But so what? Plausibly…
General relativity is true or adequate, describing with sufficient accuracy the full birth and growth of space from a singularity.
See this page to analyze 3 arguments
This is relevant because,
“If we push backwards far enough, we find that the universe reaches a state of compression where the density and gravitational force are infinite. This unique singularity constitutes the beginning of the universe—of matter, energy, space, time, and all physical laws. It is not that the universe arose out of some prior state, for there was no prior state. Since time too comes to be, one cannot ask what happened before the initial event. Neither should one think that the universe expanded from some state of infinite density into space; space too came to be in that event. Since the Big Bang initiates the very laws of physics, one cannot expect any scientific or physical explanation of this singularity.” [Bruce Reichenbach, “Cosmological Arguments,” in The Stanford Encyclopedia of Philosophy (2017)]
But so what? Plausibly…
Any Universe eternally expanding on average ends up requiring the possibility of infinitely-fast (and therefore faster-than-light) travel speeds for inertial objects. See experts on this, 1, elaboration of the concept2, and a simplified illustration 3.
See this page to see details and see:
This is relevant because space has been expanding, and yet an object traveling infinitely fast in space is impossible. (It both produces philosophical absurdities and violates the causality principle in Einstein’s special relativity).
But so what? Plausibly… … [All forthcoming]
• Alexander Vilenkin: “It is said that an argument is what convinces reasonable men and a proof is what it takes to convince even an unreasonable man. With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe. There is no escape: they have to face the problem of a cosmic beginning.” [Many Worlds in One (Hill and Wang, 2006), 176.]
• William Lane Craig & James Sinclair: “The Borde–Vilenkin–Guth (BVG) singularity theorem is now widely accepted within the physics community. As of this writing, it has gone largely unchallenged.” [The Blackwell Companion to Natural Theology (Blackwell, 2004), 142.]
• Gott-Li: “The question of first-cause has been a troubling one for cosmology. Often, this has been solved by postulating a universe that has existed forever in the past. Big Bang models supposed that the first-cause was a singularity… with a proper theory-of-everything, one could perhaps push through to earlier times. Inflation has solved some of these problems, but Borde and Vilenkin have shown that if the initial inflationary state is metastable, then it must have had a finite beginning also. Ultimately, the problem seems to be how to create something out of nothing.” [J. Richard Gott and Li-Xin Li, “Can the Universe Create Itself?” (1997), p.41]
• Audrey Mithani, Alexander Vilenkin: “Did the universe have a beginning? At this point, it seems that the answer to this question is probably yes. Here we have addressed three scenarios which seemed to offer a way to avoid a beginning, and have found that none of them can actually be eternal in the past. Both eternal inflation and cyclic universe scenarios have Hav > 0, which means that they must be past-geodesically incomplete. We have also examined a simple emergent universe model, and concluded that it cannot escape quantum collapse. Even considering more general emergent universe models, there do not seem to be any matter sources that admit solutions that are immune to collapse." [Did the universe have a beginning?, http://arxiv.org/pdf/1204.4658.pdf]
• James Sinclair: "Vilenkin affirms that any universe (including universes modeled by higher dimensional cosmology, pre–Big Bang cosmology, and so forth,) which, on average, expands has to connect, in a finite time, to a past boundary (pers. comm. with Sinclair, March 4, 2004).
• Alexander Vilenkin: "Our argument shows that null and time-like geodesics are, in general, past-incomplete in inflationary models, whether or not energy conditions hold, provided only that the averaged expansion condition Hav > 0 holds along these past-directed geodesics. (Borde, Guth, & Vilenkin 2003, p. 3)39 A remarkable thing about this theorem is its sweeping generality. We made no assumptions about the material content of the universe. We did not even assume that gravity is described by Einstein’s equations. So, if Einstein’s gravity requires some modification, our conclusion will still hold. The only assumption that we made was that the expansion rate of the universe never gets below some nonzero value, no matter how small. This assumption should certainly be satisfied in the inflating false vacuum. The conclusion is that past-eternal inflation without a beginning is impossible. [Many Worlds in One (2006), 175).]
Although the 2nd law of thermodynamics says the total entropy of an isolated system can never decrease over time, the Universe's entropy in fact is far from its maximal amount; its useable energy is still winding down.
For example, consider 1 simple evidence:
This is relevant because, if the Universe were past-infinite, the 2nd law of Thermodynamics demands that the universe would have already reached a state of thermodynamic equilibrium (“heat death”; no more useable energy).1
The 2nd Law of thermodynamics applies to black holes and similar types of horizons (hence the “Generalized 2nd Law”), suggesting that even in a quantum-gravity context (like the Planck era), the conclusion of the Penrose singularity theorm applies.1 This is relevant because...
- Aron Wall (Studies quantum gravity and black hole thermodynamics as a Lecturer at the University of Cambridge): “…it strongly suggests that either the universe had a finite beginning in time, or else it is spatially finite and the arrow of time was reversed previous to the Big Bang [i.e. tornadoes put houses back together, and eggs unscrambled themselves]. In the latter case, it could still be said that the universe had a beginning in a thermodynamic sense, because both branches of the cosmology would be to the thermodynamic future of the Big Bang” [Classical and Quantum Gravity Vol 30 No 16 (2013), p.27 on arXive.]
Using pure a priori reasoning, we can discern that the the number of previous events up until now needs to be finite in number, meaning there was inevtiably a first event.
See this page to explore two arguments:
This is relevant because if the number of previous events is finite, then tracing history backwards brings one to a beginning of the first event.
A cosmic model is true wheren the contiguous whole of space and time lacks a beginning.
This is relevant because, “If we were able to construct a complete and compelling naturalistic account, the necessity of appealing to God would be diminished.” [Sean Carroll, The Blackwell Companion to Science and Christianity]