A theist and an atheist enter into a friendly dialogue about all things science, philosophy, theology, and where they overlap.

Thursday, September 19, 2013

General Relativity Entails that the Universe has No External Cause

By L.A. Mitchell

I: Introduction

The expansion of the universe, and thus the basis of the Big Bang theory, is inferred based on equations derived from the theory of relativity. The theist who uses Big Bang cosmology to argue for the existence of god must accept these equations. Are these equations consistent with the arguments used by theists? In this paper, I will demonstrate that Big Bang cosmology actually contradicts the existence of god. Many of these arguments will be based on my previous essay titled “God and Physics: Why general relativity disproves god”. This paper will serve as a better argued and more concise alternative to the last paper.

II: Preliminary Definitions

A half-open state of time can be thought of a line segment with a maximum value, but no minimum value.

A first state of time can be thought of as a line segment with a maximum value and a minimum value.

In the context of this argument, I use sufficient cause to refer to a condition that, when it has been actualized, will inevitably lead to something else. For example, if people are playing checkers, then there is also a board and pieces in use. [1] The act of playing checkers requires the use of a board and pieces.

III: Entailment Argument

P1: Every state of the universe is sufficiently caused by a previous state.
P2: If every state of the universe is sufficiently caused by a previous state, then every state of the universe has a causal explanation with reference to another state.
P3: If every state of the universe has a causal explanation with reference to another state, then there is no state of the universe that was not caused by a previous state of the universe.
P4: An external cause of the universe can only exist if there is a state of the universe that was not caused by a previous state of the universe.
C: By P3 and P4, The universe has no external cause.
C2: God does not exist.

IV: Support for the entailment argument

The theory of general relativity is one of the most supported theories in science. The Hafele-Keating experiment demonstrates time dilation, which is a prediction of general relativity. The orbit of Mercury is experimental vindication of the theory of relativity’s equations. For many centuries, it was noted that the orbit of Mercury was slightly different from what Newton’s equations would predict. Instead of orbiting in a perfect ellipse like other plants, the orbit of Mercury precesses (which means it does not return to the same point after one orbit, but shifts slightly). When Einstein calculated the orbit of Mercury using the equations of general relativity, it predicted the orbit of Mercury with perfect accuracy. This is a strong indication that the theory of relativity is true.

Physicists derive equations from relativity called metric tensors (or metrics for short), which describe the geometric and causal structure of space-time. Ever since Einstein created general relativity in 1915, four physicists have derived metrics from his theory that describe the universe we live in, which are now called Friedmann-Lemaitre-Robertson-Walker (FLRW) metrics. The FLRW metric describes a universe that is isotropic, homogenous, and expanding. These metrics also state that every state of time is half-open.

The reason why this is true is that FRW models of the universe are singular. This means that it has an ideal point which is never reached. According to FRW, there is no T=0 state. This is because there are no space-time coordinates where T is equal to zero. Thus, every state of time on a FRW model is half-open. [2]

If every state of time is half-open, then this creates problems for a first state of time. A first state of time has a minimum value and a maximum value. However, this contradicts the theory of relativity. The theory of relativity tells us that every state of time must have no minimum value, but a maximum value. Therefore, the theory of relativity tells us that a first state of time does not exist. Not only that, but the existence of a first state of time would actually be impossible! This diagram is useful for imagining a FRW universe.

Every end-point (represented by the U shape) sufficiently causes the next end-point, and is sufficiently caused by a prior end-point. If one end-point represents the first hour after the Big Bang, and the next end-point represents the second hour after the Big Bang, then the first hour after the Big Bang sufficiently causes the second hour, because once it has been actualized, it will lead to the second hour. The first premise is warranted, and I believe that the other premises logically follow from its truth.

V: Big Bang Cosmology

The argument I give is consistent with standard Big Bang cosmology. The universe still had a beginning in the sense that every state of time must be less than 13.9 billion years old, the age of the universe. In algebraic terms, if T represents a state of time, then every T < 13.9 billion years ago. I think this explanation will solve any questions about how my view of the universe is compatible with standard Big Bang cosmology, which has a finitely old universe. As the Catholic physicist E.A. Milne writes, ‘’the Universe is meaningfully infinitely old because infinitely many things have happened since the beginning”. [3]

Some may argue that the initial cosmological singularity represents a beginning point. This is refuted by FRW models, which state that the singularity is merely an ideal point. However, some arguments can be made against a physical interpretation of the singularity. For example, the philosopher of physics Quentin Smith has pointed out problems with this interpretation. The singularity supposed to have infinite temperature, but it’s a zero dimensional point. Temperature relates to molecules moving around, like spreading out when heated, or getting closer together when cooled. How can temperature make any sense at a zero-dimensional point, which by definition, has no movement? [4] Dr. Craig also points out that a physical object with no duration and no physical extension hardly qualifies as a physical thing at all. [5]

VI: Conclusion

The theory of relativity contradicts the idea of a first cause of the universe. There is no easy way for the theist to escape this situation. One can deny the theory of relativity and a FRW model of the universe, but this entails that Big Bang cosmology is false, and that it cannot offer any support for the existence of god. The only plausible solutions are to invoke a more complex idea of gods causal relation with the universe, which will have problems being consistent with mainstream cosmology.

VII: References
  1. “Causation and Correlation.” 9.2 Causality. N.p., n.d. Web. 11 Sept. 2013.
  2. Halvorson, Hans, Halvorson,. “Cosmology and Theology.” Stanford University. Stanford University, 24 Oct. 2011. Web. 11 Sept. 2013.
  3. Milne, E. A., 1948. Kinematic Relativity, Oxford: Clarendon Press.
  4. “Does God Exist?” ReasonableFaith.org. N.p., n.d. Web. 11 Sept. 2013.
  5. Craig, William L., and Quentin P. Smith. Theism, Atheism, and Big Bang Cosmology. N.p.: Clarendon Paperback, 1994. Print

1 comment:

  1. The "last paper" referenced by Mitchell can be found here: http://doubtingdave.com/god-and-physics-why-general-relativity-disproves-god/2/