In this blog post, we look at the second premise and our justifications for thinking that the universe began to exist out of nothing.
Our first scientific argument for believing that the universe began to exist is the expansion of the universe.
General Theory of Relativity
In 1917, Albert Einstein made a cosmological application of his gravitational theory, General Theory of Relativity. To his dismay, Einstein found that his theory of relativity is inconsistent with an eternal universe unless he fudged the equations (which he did by dividing by zero) in order to offset the gravitational effect of matter. As a result, Einstein’s universe was balanced on a razor’s edge, and the least deviation would result in a universe that is either imploding or expanding.
Friedman-Lemaitre Model (aka The Standard Big Bang Model)
By taking this part of Einstein’s theory seriously, the Russian mathematician Alexander Friedman and the Belgian astronomer George Lemaitre were able to formulate independently in the 1920s solutions to his equations which predicted an expanding universe.
Confirmation by Edwin Hubble
In 1929, the American astronomer (and agnostic) Edwin Hubble showed that the light from distant galaxies is systematically shifted toward the red end of the spectrum. This redshift was taken to be a Doppler effect indicating that the light sources were receding in the line of sight.
The model does not describe the expansion of the matter in the universe into empty space but rather the expansion of space itself. The galaxies are at rest with respect to space but the space itself is expanding. Think of galaxies as buttons on a balloon. As the balloon inflates, the buttons grow farther apart. This is what is happening in our universe.
William Lane Craig states, “This has the astonishing implication that as one reverses the expansion and extrapolates back in time, the universe becomes progressively denser until one arrives at a state of infinite density at some point in the finite past. This state represents a singularity at which spacetime curvature, along with the temperature, pressure, and density, becomes infinite. It therefore constitutes an edge or boundary to spacetime itself.”[1]
P.C.W. Davies comments, “If we extrapolate this prediction to its extreme, we reach a point when all distances in the universe have shrunk to zero. An initial cosmological singularity therefore forms a past temporal extremity to the universe. We cannot continue physical reasoning, or even the concept of spacetime, through such an extremity. For this reason most cosmologists think of the initial singularity as the beginning of the universe. On this view the big bang represents the creation event; the creation not only of all the matter and energy in the universe, but also of spacetime itself.[2]
The 2nd Law of Thermodynamics
Our second scientific argument for believing that the universe had a beginning is the evidence from thermodynamics. According to the second law of thermodynamics, processes taking place in a closed system always tend toward a state of equilibrium. In other words, unless energy is constantly being fed into a system, the processes in the system will tend to run down and quit.
As an example, if I had a bottle that was a sealed vacuum inside, and I introduced into it some molecules of gas, the gas would spread itself out evenly inside the bottle. It is virtually impossible for the molecules to retreat, for example into one corner of the bottle.
Let’s consider another example. Suppose someone enters a room and discovers a cup of coffee which is still warm. He would be able to tell that it had not been there forever; in fact, given the right information, he could even calculate how long it had been cooling off. The second law states that the cup will cool off and the temperature of the room will move toward a state of uniform temperature distribution.
Based on the second law of thermodynamics, we can conclude that the universe can’t be eternal because otherwise the universe would already be out of energy. We know it has energy based on the fact we still have stars. Every star has an end date, they are not eternal. Eventually energy will disperse in the universe and there will be no stars. Just lifeless chunks of matter.
For further reading on this subject, be sure to check out the following resources:
Reasonable Faith: Christian Truth and Apologetics by William Lane Craig
Scaling the Secular City: A Defense of Christianity by J.P. Moreland
I Don’t Have Enough Faith to be An Atheist by Frank Turek and Norman Geisler
The Blackwells Companion to Natural Theology edited by William Lane Craig and J.P. Moreland
End Notes
1. Reasonable Faith by William Lane Craig, 126.
2. P.C.W. Davies, “Spacetime Singularities in Cosmology,” in The Study of Time III, ed. J.T. Fraser (Berlin: Springer Verlag, 1978), 78-79.
