In 1927, Monsignor Georges Lemaître, a Catholic priest, noted cosmologist, and colleague of Einstein’s, postulated what would later come to be known as the Big Bang theory. Lemaitre theorized that galaxies were not moving in fixed Euclidean space but rather that the space between the galaxies was stretching and growing (which might be analogized by a balloon being inflated).
Today there is only a finite distance between galaxies, so we know that the universe could not have been expanding forever in the past. All of the points must have been arbitrarily close to one another at some time in the finite past. If the Big Bang marks the initial expansion of the universe, then could it be the beginning of the universe?
Fr. Lemaître’s hypothesis of the expansion of our universe, which was confirmed by observations made by the astronomer Edwin Hubble in 1929, enabled other physicists to formulate theorems (proofs) about the necessity of a beginning. The most recent one is called the Borde-Vilenkin-Guth proof (or the BVG proof).
In this post, we’ll discuss the BVG proof and entropy as physical and scientific evidence for the beginning of physical reality. We’ll then look at the ancient philosophical dictum, “nothing comes from nothing.”
In 2003, three scientists by the name of Borde, Vilenkin, and Guth formulated an elegant proof of a boundary to past time in all cosmologies where the average Hubble expansion is greater than zero.
While one could write pages on the BVG Theorem, here, we will summarize it in 5 points:
The BGV proof is virtually universally applicable and very difficult to disprove (because it has only one condition). It even applies to eternal inflation, where the universe's expansion lasts forever throughout most of the universe. Vilenkin states it as follows:
“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.” —Alexander Vilenkin
We should not underestimate the implications of Vilenkin’s statement. He is claiming that the proof is valid almost independently of the physics of any universe (except for the one condition that the average expansion rate of the universe or multiverse is greater than zero). He is further claiming that such a universe without a beginning is impossible!
At this point, it seems as if physics is coming very close to proving an absolute beginning of physical reality itself. If no physically realistic exception can be found to this proof (and to the problems of an eternally static universe), it would make an absolute beginning of physical reality quite probable.
This takes us to the threshold of metaphysics. Before moving in that direction, let’s first consider another vastly applicable datum that also indicates the likelihood of a beginning of physical reality: that of entropy.
Entropy is a technical concept that measures the amount of thermal energy in a system available to do work, but it can also be used to describe the “disorder” or disorganization of a system.
Entropy can be explained like so: work requires a change of one form of energy into another. In a physical system, the available amount of energy decreases when work is done. Because energy is released by changes in molecular order (think of wood burning or ice melting or even water boiling), ordered molecular arrangements lose some of their order and become "disordered." This measure of disorder (or loss of energy available to do work) is known as entropy.
The famous Second Law of Thermodynamics says that, in isolated systems, entropy always increases or stays the same and never decreases. That is why some processes are irreversible. If a process changes the entropy, then it can only go one way: the way that entropy (disorganization) increases. That is why dead bodies decompose, but do not recompose!
Of course, these are, ultimately, probabilistic statements. Entropy can have random fluctuations downward, but these are usually very tiny decreases, and the larger the decrease in entropy, the more unlikely it is to happen.
Entropy is a universal phenomenon and has relevance to the question of whether the universe had a beginning.
If the universe did not have a beginning, it would have been around for an infinite time. In a sense, the universe would then be a “perpetual motion machine,” a system that never “runs down” or “wears out,” violating the Second Law of Thermodynamics.
The argument against an infinite universe can be broken down into five steps:
Therefore, the universe has not existed for an infinite amount of time (and therefore has a beginning). The fact that our universe must have had low entropy at its beginning is one of the arguments for a finely tuned universe.
The discussion in the two foregoing sections shows that the preponderance of cosmological evidence favors a beginning of the universe where, prior to which, there was no physical reality. Is this evidence sufficient to show the beginning of physical reality itself?
If the beginning of physical reality is a point at which everything physical (including mass energy, space and time, and physical laws and constants) came into existence, then prior to this beginning, all aspects of physical reality would have been nothing. It seems likely that this is the case because quantum gravity, the general theory of relativity, and field theory all suggest that everything physical is interrelated.
This means that prior to the beginning, physical reality was most likely nothing, including physical space and time, physical mass and energy, and the laws and constants—every aspect of physical reality.
This encounter with “nothing” brings us into the domain of metaphysics, which many physicists have unwittingly entered because of the strong evidence for a beginning of physical reality. However, It seems that any attempt to hypothesize something coming from nothing will result in a host of problems—such as “sneaking” something into nothing, equivocating on the term “nothing,” and/or postulating an unacknowledged transphysical mentative state which allows laws (without physical reality) to generate the whole of physical reality.
If we are to avoid these confusions, we should follow the example of Parmenides and allow “nothing” to be nothing (the complete absence of reality). This means not putting any content into “nothing” such as continuity, dimensionality, or orientability (as might be found in a spatial manifold) or confusing “nothing” with physical laws without a physical universe (entailing an unacknowledged transphysical mind or mentative state). Anything else argues the most fundamental of contradictions.
We can know something else about nothing—namely, that it can only do nothing. As metaphysicians since the time of Parmenides have recognized, “From nothing, only nothing can come.”
We may now proceed to our conclusion—combining a first premise from physics and a second premise from metaphysics:
Premise 1: Space-time geometry proofs and entropy give physical and scientific evidence for a beginning of physical reality (prior to which physical reality was literally nothing).
Premise 2: From nothing, only nothing comes (apriori true).
In light of these two premises, it is highly likely that the universe came from something which is not physical reality (i.e., beyond physical reality). This is commonly referred to as the “transcendent cause of the universe” (or “a transcendent cause of physical reality”)—in short, “a creator.”
Interested in learning more about the beginning of the universe? Download a free chapter from Father Robert Spitzer's book, "The Soul's Upward Yearning."