Is the Concept of God Rational?

Ernest Hemingway famously wrote “All thinking men are atheists.”[1] This is often the position of those who claim the concept of a supreme being—commonly known as God—should simply be dismissed as a delusional fairy tale of the simple-minded and uneducated. But is this assertion valid? In contrast with such an attitude, numerous men and women of great intellect throughout history and into the present age have held the view that belief in an ageless, powerful, and creative intelligence is not only beneficial but rational.  If this proposition is indeed a sensible one, even in theory, the ramifications are important enough to merit further enquiry. To stimulate this quest, two logical positions—the cosmological and moral arguments—are introduced to show that the existence of God is indeed a rational proposition worthy of further study.

Before we explore the validity of belief in a supreme being, note the following: (1) although the author is a born-again Christian, the arguments proposed in this essay in no way demonstrate supremacy of faith in the God of the Old and New Testaments. (2) As with most truths, the evidences are not presented as final proof of the existence of God. Rather, they show such a belief is rational and are intended to generate curiosity for further exploration of the topic.

To commence our investigation, we start at the beginning of all things.

The Cosmological Argument for God

To establish the idea of God as a rational worldview, we first consider the origin of the universe. As presented by Copan, the kalam cosmological argument posits the following:

  1. Whatever begins to exist has a cause of its beginning.
  2. The universe began to exist.
  3. Therefore, the universe has a cause of its beginning.[2]

The first assertion follows the conventional understanding of modern science. For example, Hawking writes, “All the evidence seems to indicate, that the universe has not existed forever, but that it had a beginning, about 15 billion years ago.”[3] Much research by world-class physicists, mathematicians, and astronomers has gone into development of this consensus view. A primary supporting proof for this theory is the 2nd Law of Thermodynamics, which states that heat always moves from hot to cold toward equilibrium. At some point far into the future, all heat in existence will have dissipated. This provides a sound basis for the temporality of the universe since, as Copan observes, “If the universe were eternal, why has this heat death not already occurred?”[4]

The second claim—that the universe began to exist—is evident through the concept of an actual infinity. If the universe has always existed, then it has existed from eternity, and is therefore infinitely old. Since part of an actual infinity is another actual infinity, the universe would have had to have already passed through an eternity to reach its present state. But according to Geisler and Brooks, this is logically infeasible because the cosmos cannot, in fact, have passed through infinity to reach today.[5] To exist as it is and for us to be observers, it must have had a beginning. Again, we agree with Hawking.

The third claim is where we encounter God. If we accept that the physical universe had a beginning, then it was certainly caused. The question is, did that which produced the universe itself have an origin? Has this causality been going on endlessly with one caused thing begetting another? As with the argument for the universe not having an origin, we are faced with the issue of infinite regress. If everything with a cause were itself caused, we are stuck with no beginning. The rational choice, then is that the ultimate cause of everything is itself beginningless.

If this is true, then what is this ultimate cause? If the originator has no origin, then logically it is eternal, existing outside the confines of space and time. Since the universe is massive and full of energy, the origin must be extremely powerful. Also, inexplicable order that exists within the universe—crystalline structures, seasonal cycles, and life itself—strongly implies that this first cause has intelligence and what Moreland calls “spontaneous choice.”[6] Thus, we argue that it is reasonable for an uncaused origin to have always existed and possess tremendous power and intelligence. Does this not fundamentally describe the concept of God?

We have contended that cosmology logically points to the existence of a God. But the investigation does not end here—our evidence also includes ethics.

The Moral Argument for God

Another strong evidence for the rationality of belief in God is the existence of objective moral truth. The reality of objective morality may be clear to most people (granted, not all—we will not get into that here), but how does it provide evidence to the existence of God? This is where we must look at the nature of values themselves. Moral truths are not simply fact claims—they tell us what ought to be. They act as imperative.  One should not steal. One should not torture.  One should not murder. Violation of such ethics brings with it a sense of personal guilt that goes beyond societal shame.[7] Essentially, as imperatives, moral laws have a sense of force behind them. Where does this force come from? Natural evolution over time? Does it not make more sense that an uncaused cause of everything created these laws and upholds them? And if something caused these morals to exist, would that entity not have to have the same characteristics of power and intelligence some ascribe to God?


We have argued that belief in an ultimate deity is a rational worldview worth considering. That claim is shown to be supported by both the cosmological and moral arguments. The evidence discussed herein only scratches the surface of logical and natural proofs developed over years of honest study and research by the cited experts and others. It is the hope of this author to plant a seed of interest for the reader to pursue further study of this important topic.

Works Cited

Copan, Paul and William Lane Craig. 2018. The Kalam Cosmological Argument: Volume I. New York New York: Bloomsbury Academic.

Geisler, Norman L. and Ronald M. Brooks. 2013. When Skeptics Ask: A Handbook on Christian Evidences. Grand Rapids, Michigan: Baker Books.

Hawking, Stephen. “The Beginning of Time.” (Accessed 28 July 2019)

Hemmingway, Ernest. 1929. A Farewell to Arms. United States: Charles Scribner’s Sons.

Moreland, J. P. “Arguments for the Existence of God.” Defending the Faith I—CSAP 601. Biola University, Los Angeles. 2019.

[1] Ernest Hemmingway, A Farewell to Arms, (United States: Charles Scribner’s Sons) 8.

[2] Paul Copan and William Lane Craig, The Kalam Cosmological Argument: Volume I (New York, Bloomsbury Academic), 4.

[3] Stephen Hawking, “The Beginning of Time,” accessed on 28 July 2019,

[4] Paul Copan and William Lane Craig, The Kalam Cosmological Argument: Volume I, New York, Bloomsbury Academic, 7.

[5] Norman Geisler and Ronald Brooks, When Skeptics Ask: A Handbook on Christian Evidences, Grand Rapids, Michigan: Baker Books, 11.

[6] J. P. Moreland, “Arguments for the Existence of God,” Defending the Faith I—CSAP 601, Biola University, 3.

[7] Ibid, 5.

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