How did Norm Geisler Argue for the Existence of a Theistic God?
From the first principles of thought, from the laws of logic, and from reasoning from effects to their causes, we can and should know that there is a God. But which God? There are several competing worldviews (or God-world models) that present very different Gods/ gods: Atheism, Agnosticism, Pantheism, Panentheism, Polytheism, Finite-Godism, Theism, and Deism. As a point of reference, when the Apostle Paul was speaking to epicurean and stoic philosophers in Athens (Acts 17), Paul was the theist, the Stoics were pantheists or panentheists, and the Epicureans were functional atheists who may have ranged between deism, finite godism, polytheism, and monism-pantheism. The theistic view maintains a wide gulf between Creator and creation and says that God is to the world like a painter is to his painting, a programmer is to his program, and a gardener is to his garden. In panentheism, lines begin to blur between Creator and creation.
After clarifying which concept of God reason leads towards, Norm typically used five arguments for God. His first argument is what he called the horizontal form of the cosmological argument. It argues from a beginning of the world in time to a Beginner. The second argument he called the vertical form of the cosmological argument. It argues from contingent being to Necessary Being. Whereas horizontal suggests a timeline, vertical indicates metaphysical or ontological dependency. The horizontal tends to appeal to science-minded people who respect the implications of the second law of thermodynamics, general relativity theory, and the expansion of the universe from a beginning point. But it leads to a vague idea of God. The vertical may appeal to those who are more philosophically minded. It was considered by Norm to be the strongest and most important argument, and concludes not with a vague God but a God who seems to be described in the Bible (e.g., Exod. 3:13-16; Isaiah 44-51; Col. 1:1-2:15, Rom. 4:17; Acts 17:23-31; Rev. 1:8). The vertical argument is showcased particularly in Geisler’s books Philosophy of Religion, Christian Apologetics, and God: A Philosophical Argument from Being. It is also discussed in Christopher T. Haun, The Geislerian Argument for God (Arlington, TX: Bastion Books, 2026).
The third argument he presents is the teleological argument. It argues from designs to a Designer. The designs he focused on were the fine-tuning of the cosmos before it began to expand and the information encoded into all living cells. He talks about the anthropic principle, specified complexity, and irreducible complexity. Norm was keenly aware that both of these lines of evidence were instrumental in converting Anthony Flew, once known as the world’s most notorious atheist, into a deist. While he did not consider this is strongest argument for God, he was nevertheless pleased to use it regularly. The vertical argument was the main argument to prove that there is a theistic God and the argument from design was a supplemental argument to prove that God is not just an infinite, necessary, yet impersonal force (which the vertical argument arguably leaves us with) but an intelligent, personal, and purposeful being. For comparison, the Apostle Paul argued that God’s design of the world’s ecosystems was not simply just an intelligent design but one that shows his benevolence towards us. (Acts 14:17: “Yet he did not leave himself without witness, for he did good by giving you rains from heaven and fruitful seasons, satisfying your hearts with food and gladness.”) In chapters 6-8 of Philosophy of Religion, 2nd edition, Geisler and Corduan survey five forms of the teleological argument, seven forms of the moral argument, seven forms of the ontological argument, and sixteen forms of the cosmological argument. While not rejecting the most refined forms of the teleological, moral, ontological, horizontal cosmological arguments, and contingency cosmological arguments, they surprise us by conceding that several of the criticisms are valid. Geisler seems somewhat neutral in disposition to these many traditional arguments, neither fully embracing them nor rejecting them. He rather champions one specific argument for God—the existential, Thomistic, vertical form of the cosmological argument. When they could only use one argument, Geisler and Corduan would use that one best argument. When Geisler had room to use other arguments as well, he would add good-but-imperfect arguments as supplemental facets. Whereas a few Thomistic philosophers have been harsh with the imperfections of arguments presented by ID pundits, Geisler is somewhat rare in that he was a Thomistic philosopher who was an early and constant supporter of the ID movement.
The fourth argument rallied was the moral argument. It argues from the fact of moral absolutes and moral laws to a Moral Law Legislator. This argument also indicates that the God that must exist is a personal, caring, purposeful, and moral. This also provides a segue into dealing with the problem of evil, which is arguably the biggest obstacle to belief in God.
The fifth and final argument was the argument from religious need—that if there is a real need (not imagined but real) for God in humans, there must be a real referent to satisfy that need. He followed C.S. Lewis closely on both. As a nice touch, he added a collection of several quotes from famous atheists who confessed that they could not bear to live with the atheism they had chosen. These arguments perhaps reached some people that the other arguments failed to reach.
In one sense, using these five arguments was like a locksmith using five different skeleton keys to lift the tumblers on a variety of locks. Most of the intellectual obstacles to belief in God would be severely challenged if not outright destroyed. While Norm was an extremely formidable defender on all twelve points in his system, throughout his long career his specialty was arguably points 1-3. In his final public lecture, Norm chose to speak on points 1-3 (of his twelve points that show Christianity is true apologetic) and presented them as if they were really what the world most needed to hear and apologists most needed to offer. See Norman Geisler,“Defending the Faith in the Postmodern World,” 2017.
Norm Used 5-7 Arguments for the Existence of God
Norman L. Geisler was a classical Christian apologist who loved to “destroy arguments and every lofty opinion raised against the knowledge of God” (2 Corinthians 10:5). He gained some notoriety as a powerful debater for God in public debates with noteworthy secular humanists on American college campuses in the 1970s and 1980s.
In his Systematic Theology, Norm recommends six arguments for God: (1) the horizontal form of the cosmological argument, (2) the vertical form of the cosmological argument, (3) the teleological argument, (4) the ontological argument based on the idea of a Perfect Being, (5) the ontological argument based on the idea of a Necessary Being, (6) the moral argument. [Norman Geisler, Systematic Theology, Volume 1 (Bastion Books 2002, 2025), 27-38. Note that he does not hold that the two forms of the ontological arguments actually prove that a God exists.]
In his “twelve points that show Christianity is true” lectures and book, which he tailored towards college students and the general public, Norm recommends five arguments for the existence of God: (1) the horizontal form of the cosmological argument, (2) the vertical form of the cosmological argument, (3) the teleological argument, (4) the moral argument, and (5) the argument from religious need. [Norman Geisler, The Twelve Points that Show Christianity is True (NGIM, 2012), 16-25.]
In his book Christian Apologetics, Norm offers only one proof for the existence of God, the argument from Being, which he also refers to as the vertical form of the cosmological argument. [Norman Geisler, Christian Apologetics (Baker, 1976), …. Christian Apologetics, Second Edition (Baker, 2013), 265-279.] In 2015, Norm published a booklet titled God: A Philosophical Argument from Being (Bastion Books, 2015) which was essentially this exact same argument with very minor revisions and slight expansion.
Norm Focused on the Metaphysical Argument for God
While he was delighted to use variations of the kalam cosmological argument, teleological arguments, the moral argument, and the argument from religious need to make his cumulative case for the existence of the God of the Bible, he thought the “metaphysical argument” of Aquinas, which he called the “vertical cosmological argument,” was the most profound, most powerful, and most foundational argument for God. “The strongest argument for the existence of God is the ‘vertical form’ of the cosmological argument.” (Reference). It was arguably his favorite meditation and the area that he hoped to see more metaphysical philosophizing devoted to. Towards the end of his life, in 2015, when I asked him what he would do if he had his whole life to live over, without hesitation he said he would earn bachelors, masters, and PhD degrees in philosophy from schools that focused on metaphysics. When he asked me to publish his booklet God: An Argument from Being for him, it was very clear that the topic was extremely dear to his heart and that he was eager to get feedback from other philosophers about any weaknesses in the argument he might reconsider and bolster.
Not the Same as Leibniz’s Contingency Argument
This Thomistic “metaphysical argument” argument is somewhat similar to the more famous “contingency argument” of Gottfried Wilhelm Leibniz and could arguably be classified as a contingency argument. However, Leibniz’s contingency argument uses the principle of sufficient reason (PSR) and Aquinas’s metaphysical argument does not. Norm argued that the use of the PSR made the former logically weaker than the latter (add reference). In some of his earlier public debates with secular humanists, Norm echoed this by using an illustration about effects needing causes, which illustrates the PSR-based argument, taken from Richard Taylor’s book on metaphysics (Reference1, Reference 2).
From Beings to Being? From existents to existence?
Norm was trying to argue from being itself rather than from beings. As Wilhelmsen wrote:
The Summa Theolgiae‘s famous “five ways” of proving the existence of God are not strictly metaphysical arguments, for they are rooted in beings rather than in being; the act of existence plays no role in them. Aquinas develops his properly metaphysical argument for the existence of God in On Being and Essence [De ente et essentia.] [Frederick D. Wilhelmsen, The Paradoxical Structure of Existence (Routledge, 2017), xxvi fn. 26
Norm was an Existential Thomist Metaphysician
Norm was known mainly as a classical Christian apologist and as an evangelical theologian. But arguably he was first and foremost a philosopher of existential thomistic metaphysics. He was a thomistic existentialist, an existential thomist. He was intrigued with and encaptivated by “De Ente reasoning” from his introduction to it in 1947 until the end of his life in 2019.
Norm tended to think of Thomism primarily as a moderate realist system of metaphysics and epistemology. He appreciated Gilson, Owens, Wilhelmsen, and the other Existentialist Thomism thinkers in part because they, with their “De Ente reasoning” saw a very powerful argument for the existence of the God of theism.
Norm frequently recommended existential Thomists to his students: Étienne Gilson Being and Some Philosophers (1949); Étienne Gilson God and Philosophy (1941); Joseph Owens An Elementary Christian Metaphysics (1963). The syllabi from his “Introduction to Metaphysics” courses at Veritas International University in the 2008-2015 era required the following Thomistic textbooks: Thomas Aquinas, On Being and Essence (de ente et essentia); Étienne Gilson, Unity of Philosophical Experience (1937); Joseph Owens, An Elementary Christian Metaphysics (1963); Reginald Garrigou-LaGrange, God: His Existence and Nature (1934); Frederick Wilhelmsen, Man’s Knowledge of Reality (1959). [https://normangeisler.com/thomism]
His own contributions to Aquinas’s metaphysical argument may be found in several books:
- Thomas Aquinas: An Evangelical Appraisal (Bastion Books, 2025)
- Christian Apologetics, 2nd Edition (Baker, 2012)
- Philosophy of Religion, 2nd Edition (Wipf & Stock, 2004)
- God: A Philosophical Argument from Being (Bastion Books, 2015)
- “God, Evidence for > A Cause Right Now,” The Big Book of Apologetics (Baker, 2012), 196.
- “First Principles,” The Big Book of Apologetics (Baker, 2012), 170-172.
- “The Universe Needs a Cause for its Continuing Existence,” When Skeptics Ask, 2nd Ed. (Baker, 2013), 12-13.
- Twelve Points that Show Christianity is True (NGIM, 2016), 28-30.
- Norman Geisler, Systematic Theology: In One Volume (Bastion Books, 2021), 24-25.
- Video: “Defending the Faith in a Post-Modern World”, 2017. (Ref.)
Click here (redirects to BastionBooks.com) to read more about Norman Geisler’s “vertical cosmological argument” or Thomistic metaphysical argument.