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An ontological and teleological argument for the existence of God

Philosophy of Religion Essay 2021


The existence of God is a controversial topic which potentially has many implications for how one ought to live. In philosophy, the discussion focuses on three main arguments and their various models: the ontological argument, the teleological argument, and the cosmological argument. This evaluation will focus on the former two. Alvin Plantinga’s modal ontological argument is often postulated as the most compelling of its kind, drawing from modal logic to demonstrate that if God exists in some possible world, then God exists necessarily in the actual world. The argument falls apart, however, when the fundamental “possibility premise” is reformulated to demonstrate that if God does not exist in some possible world, then God necessary does not exist. Responses to this objection fail to offset the balance of intuitions at the core of the debate, and so the argument fails to prove that God exists. The fine-tuning teleological argument, one of the most popular of its kind, relies upon intuitions about apparent design in the universe. A life-permitting universe is much more likely to have come about if there were a designer – and this remains true even when postulating a multiverse. However, being largely a probability argument, fine-tuning alone fails to prove God’s existence. Nonetheless, because intuitions are very much in favour of theism, the argument makes a valuable contribution to a cumulative argument for the existence of God.


An ontological argument attempts to show that God exists using premises derived solely from reason (an a priori argument). The first and most well-known ontological argument was formulated in the 11th century by St Anselm of Canterbury. In his Proslogion, Anselm defined God as “that than which nothing greater can be conceived,” arguing that such a being must therefore exist, for it is greater to exist in reality than to exist in the understanding alone. The success of Anselm’s argument remains controversial, though it is generally accepted that various objections have proved fatal (eg, Gaunilo’s greatest island and Kant’s “existence is not a predicate” criticism). Remodelling Anselm, Alvin Plantinga’s modal ontological argument may be one of the strongest constructions of the ontological argument to date – however, it ultimately fails. Plantinga employs modal logic semantics to argue that if God is possible, then God is necessary, and therefore exists. The argument proceeds as follows:

1. It is possible that a maximally great being (MGB) exists.

2. If it is possible that a MGB exists, then there is a possible world in which a MGB exists.

3. If a MGB exists in some possible worlds, then a MGB exists (and is necessarily maximally excellent) in all possible worlds.

4. If a MGB exists (and is necessarily maximally excellent) in all possible worlds, then a MGB exists (and is necessarily maximally excellent) in the actual world.

5. Therefore, a MGB (ie God) exists in the actual world.

(Inspired by Meister’s formulation, 2009)

A basic understanding of modal logic semantics is required here. A possible world is a world that is logically possible (that is, it contains no contradictions). To describe something as necessary is to say that it exists in all possible worlds. On the other hand, if something is impossible,it exists in no possible world, and if something is contingent, it exists in some possible worlds. Plantinga defines God as a maximally great being (MGB). A MGB has all “Great-Making Properties"[1] (properties that are better to have) to their maximal extent (referred to as maximal excellence). Therefore, God is omnipotent, omniscient, omnibenevolent, etc. By extension, God must be a necessary being, because being necessary is a better property to have.

Plantinga’s modal ontological argument is formally valid (its premises suit the conclusion), so the concern is whether it is sound (whether its premises are true). The strongest objections target the viability of the first premise, “It is possible that a MGB exists.” Sceptics might argue that the concept of a MGB is incoherent, because:

o there is contradiction in a single Great-Making Property (eg, the omnipotence paradox),

o there is contradiction between two Great-Making Properties (eg, omnibenevolence and omnipotence), or

o Great-Making Properties do not align with observed facts about the universe (eg, problem of evil).

However, none of these seem to prove convincing, as many such objections have satisfactory replies. Similar things can be said of the objection that Plantinga’s argument is question begging.[2] Another objection is that it may be the case that modal logic is being used incorrectly in this ontological argument. There is no consensus regarding what ontological or functional role possible worlds should play in metaphysical discussion. However, this seems to be less of an objection and more of a precautionary footnote in the case that a consensus should ever be reached.

Perhaps the most powerful objection to the modal ontological argument is the reverse argument, starting from the premise that, “It is possible that a MGB does not exist.” Using the same modal logic, the sceptic can claim that “Therefore, a MGB (ie God) does not exist in the actual world.” If a MGB, being necessary by definition, can fail to exist in a possible world, then a MGB exists in no world. The point is made that our modal intuitions cannot be relied upon. This objection directly targets the “possibility premise” in Plantinga’s argument, which is largely supported by intuition – it seems true that God could possibly exist. However, proponents of the reverse argument argue that a person can have equally strong modal intuitions about the possibly of God not existing. If a person does not already accept the claim that there is a MGB being, then they are unlikely to be persuaded that it is more reasonable to accept Plantinga’s premise over the reverse premise. William Rowe, considering this objection, adds that if God’s existence is only possible in the sense that God may or may not exist in the actual world, then God’s greatness could be superseded by a God who could not fail to exist (2009). Because God is defined as maximally great, this leads to a contradiction.

Plantinga anticipates the central point of this objection and concedes that not everyone will accept the premise that God possibly exists. However, he adds, there is nothing unreasonable or irrational in accepting this premise. Plantinga’s modal ontological argument, he himself claims, “establishes, not the truth of theism, but its rational acceptability,” which surely achieves something for natural theology.

Elizabeth Burns argues that Plantinga concedes too much here and proposes a reconstructed argument (drawing from work done by Iris Murdoch) for a belief in a God who exists necessarily. Burns argues that we can reason from our experience of different degrees of goodness that there exists a maximal goodness, of which there is no higher good. Our ability to identify goodness in the world can only be explained by “the necessary existence of a perfect standard of goodness,” which is God. Burns formulates the argument as follows (summarised):

1. It is possible that there is Maximal Excellence (= Unsurpassable Greatness) in every possible world.

2. Necessarily, Maximal Excellence exists in any world that contains degrees of goodness.

3. Varying degrees of goodness exist in the actual world.

4. If (3), necessarily, Maximal Excellence exists in the actual world, and it is reasonable to suppose that all possible worlds contain degrees of goodness.

5. If (4), necessarily, Maximal Excellence exists in all possible worlds.

6. Therefore, Maximal Excellence (= Unsurpassable Greatness) exists.

We can refer to Jacobus Erasmus’ similar attempt (drawing from the Moral Argument for God’s existence) to expand upon Burns’ argument. Erasmus notes that certain properties are (qualitatively) greater than others, and certain properties are objectively greater than others (that is, their greatness exists independent of humans). For example, being healthy is greater than being unhealthy. Erasmus argues that these observations are strongly intuitive, and to deny that certain properties are qualitatively and objectively greater than others lead to uncomfortable consequences. Additionally, those who deny these intuitions cannot consistently claim that others are unreasonable if they accept these intuitions, as this implies that one claim is greater than another. Erasmus concludes that the best explanation for the objective truth value of some greatness-propositions is the existence of a MGB, serving as the metaphysical basis for greatness. And so, the argument takes familiar shape: if it is possible that greatness exists, then a MGB (ie God) necessarily exists.

At the core of the debate outlined here is the trustworthiness of intuitions. At first glance, Plantinga’s modal ontological argument seems as convincing as an ontological argument can be in attempting to prove God’s existence. It should be noted that, as Bertrand Russell observes, it is much easier to be convinced that ontological arguments do not work than it is to describe just exactly what is wrong with them. In an attempt to demonstrate where Plantinga’s argument goes wrong, the reverse argument makes the valid point that it is not obvious whether a MGB possibly does, or possibly does not, exist. Burns and Erasmus make a noble effort to reconstruct the argument in order to overcome the need to rely upon intuitions. While the reconstruction does still rely upon intuitions about degrees of greatness, it is apparent that this is a much stronger intuition, and difficult to counter. The main issue with this reconstruction, for the purposes of this evaluation, is that it no longer takes the form of a true ontological argument – it depends upon the human experience of degrees of greatness and is thus largely a posteriori. Burns predicts this objection and argues that even Anselm (the originator of the ontological argument) felt the need to offer supporting arguments – experience strengthens the a priori argument. Perhaps it is true that arguments for God’s existence are better off interwoven, but that is not the concern of this evaluation. Burns seems to admit that the reconstruction is ultimately a cumulative argument, therefore admitting that Plantinga’s modal ontological argument cannot stand on its own. The premise, “It is possible that a MGB exists,” remains problematic in an a priori sense, and so the argument fails to prove. It may well be the case, as Plantinga concedes, that some success exists in the modal ontological argument in the fact that the conclusion follows the premises, and that it is no less reasonable to accept these premises than it is to reject them. And “perhaps that is all that can be expected of any such argument” (1974).

Teleological arguments attempt to infer the existence of God from various properties of the world by arguing that they are intelligently designed. These arguments are persuasive largely due to their intuitive value. Whether or not one believes in a designer, it is difficult to deny that the physical world is design-like. William Paley is popularly known for his watchmaker analogy, in which he compares the design in a watch to the apparent design in nature. However, the modern consensus is that Paley’s argument has since fallen apart with Darwinian evolutionary theory, which describes a natural world evolving by chance. Many contemporary proponents of the teleological argument now look beyond biological process, focussing instead on universal constants. Richard Swinburne distinguishes between arguments from temporal order (design in order/beauty) and arguments from spatial order (design in complex natural objects). Of the latter kind, perhaps the most widely discussed is the fine-tuning argument. Recent developments in physics have revealed that, had the fundamental physical parameters of the universe been slightly different, life (as we understand it) would not have been possible. That is, the constants of the universe are “fine-tuned” for life. For example, if neutrons were not about 1.001 times the mass of protons, life would not be possible. If the strong nuclear force differed by 0.4%, life would not be possible. If the expansion rate of the universe differed by more than one part in 1060, life would not be possible. And the list continues.[3] The chance of life is lowered evermore by the fact that many of these constants are unrelated. Lee Smolin comments that this fine-tuning demands an explanation, and “luck will certainly not do here” (1999). Given the incredible epistemic improbability of biological life coming about by chance, the fine-tuning argument concludes that the universe must have a designer. One formulation is as follows (Craig, 2003):

1. The fine-tuning of the universe is due to either physical necessity, chance, or intelligent design.

2. The fine-tuning of the universe is not due to physical necessity or chance.

3. Therefore, the fine-tuning of the universe is due to intelligent design.

It is unsurprising that there have been many objections to the fine-tuning argument that target the second premise (being the most contentious), some of which will be briefly discussed here. One of the most interesting is the weak anthropic principle which argues that it is necessary for the universe to be fine-tuned, for if that were not the case, we would not exist to comment on the fact. Fine-tuning should not surprise us, for life can find itself only where life is possible – there is no need for deeper explanation. Swinburne dismantles this objection by applying an analogy, summarised as follows: Suppose a kidnapper traps a victim in a room with a card-shuffling machine which draws ten random cards out from ten shuffled packs of cards. Unless the draw consists of an ace of hearts from each pack, the machine will kill the victim, in which case he will not see the draw. Shockingly, an ace of hearts from each pack is drawn, and the victim thinks that this merits an explanation – perhaps the machine was rigged? The kidnapper, disagreeing, tells the victim that he should not be surprised at the draw, for he would not have been alive so see anything else. But the kidnapper is wrong. The fact that the draw was a necessary condition for it being perceived does not make the draw any less extraordinary. The point is not that we perceive fine-tuning, but that fine-tuning is there.

Perhaps the most popular objection to the fine-tuning teleological argument is the multiverse hypothesis, according to which our universe is simply one of many (maybe infinite) universes with varying constants. Given such a large number of universes, it is unsurprising that at least one of them would be fine-tuned for life. If there are many universes, the chance of a life-permitting universe coming to exist is much greater than if there were only one universe. While still largely controversial and speculative, with no experimental evidence in its defence, recent developments in inflationary cosmology and string theory have motivated some physicists to take the multiverse hypothesis more seriously. Given this, it does not seem to do the objection justice if we dismiss it based solely on its lack of support.

Robin Collins argues that, even if there were a multiverse, it would need to be produced by some multiverse generator. This mechanism, however, would itself need to be finely tuned, and would thus need to be explained. The multiverse generator could only produce life-permitting universes if the necessary background laws and processes were in place. By invoking a multiverse generator to explain fine-tuning, one only succeeds in raising the design debate up a level, regarding the design of the multiverse generator and its background laws and processes. One might then object that there may still be perfectly natural explanations for these more fundamental laws which scientific progress is yet to discover. However, as Ratzsch and Koperski note, the appeal to what science might yet discover is not itself a rival hypothesis. Swinburne adds by arguing that scientific explanation must come to an end somewhere, and it is unlikely that the universe is fundamentally unexplainable. It is reasonable then to seek personal explanation (ie mental states, intention), which implies that there exists some intelligent designer.

Along similar lines of thought, Swinburne responds to the multiverse hypothesis by application of Occam’s razor – that is, we ought to prefer the explanation which is simplest. The existence of a multiverse with a multiverse generator is a far more complex conjecture than the existence of a sole universe without a generator. In this case, we ought to prefer theism as an explanation for fine-tuning. One might then object, as J. J. C. Smart does, that positing a designer does not solve the problem, because “If we postulate God in addition to the created universe we increase the complexity of our hypothesis” (1981). This objection stems from the idea that a designer must be at least as complex as the designed object. This is problematic, however, as the majority understanding is that God is a metaphysically simple being. Smart therefore has a lot of arguing to do in order to make this objection convincing.

As it was with Plantinga’s modal ontological argument, intuitions seem to play an important role in the worth of the teleological argument. This is because the teleological argument largely relies upon probability, which inherently cannot postulate certainty. However, unlike Plantinga’s argument, these intuitions are considerably more in favour of the existence of God. Without a designer, it is highly improbable that a sole universe would be fine-tuned for life. With a designer, it is very likely, for God has many reasons to make life possible – such as, Swinburne argues, the fact that life is good and beautiful. Similar logic applies in the context of a multiverse, though perhaps the probability divide is lesser. A designed universe also has greater explanatory power than an undesigned universe, and for many physicists, fine-tuning demands explanation. C. Stephen Evans summarises by saying that “if the world appears to us to have a certain characteristic, then that is a reason to think it has that characteristic” (2018). Intuitions mean something, and it is uncontroversial to claim that the universe appears designed.[4] Even avowed atheist Richard Dawkins describes biology as “the study of complicated things that give the appearance of having been designed for a purpose” (1987). It should here be noted, however, that the teleological argument does not prove the existence of God, but merely demonstrates the profound reasonableness of such a belief. By itself, fine-tuning cannot provide sufficient reason for someone like Dawkins to adopt theism (though it might be argued that no reason would be sufficient for a man like Dawkins). The teleological argument simply constitutes one additional part of the voluminous case for theism.


In light of this brief overview of selected versions of these arguments, it seems true that both the ontological argument and teleological argument fail to prove the existence of God. They do, however, succeed in contributing to a cumulative case for the existence of God. Not one argument alone is sufficient to be able to claim to have proved God’s existence. However, one might imagine that many arguments combined could justifiably make that claim. It is apparent that much of the philosophical discussion about God is ultimately grounded in intuition. For Plantinga’s modal ontological argument, intuition can go both ways – both in favour and against the existence of God. While for the fine-tuning argument, intuition quite strongly urges in favour of God’s existence. These intuitions mean something, and people are known to trust them very regularly. Perhaps such discussion about intuition is appropriate, and to be expected, when debating the reality of a maximally great designer.




[1] And by implication, no “Lesser-Making Properties.” [2] Unfortunately, deeper discussion into these objections is beyond the scope of this short evaluation. [3] There are around twenty-five finely tuned variables. [4] Design language is difficult to avoid even in academia.





Meister, Chad V. Introducing Philosophy of Religion. Oxford: Routledge, 2009.

Burns, Elizabeth D. “The Ontological Argument.” In Two Dozen (or so) Arguments for God: The Plantinga Project. New York: Oxford University Press, 2018. https://doi.org/10.1093/oso/9780190842215.003.0008

Erasmus, Jacobus. “Why It Is Difficult To Defend the Plantinga‐Type Ontological Argument.” Heythrop Journal, 2020. https://doi.org/10.1111/heyj.13682.

Oppy, Graham. “Ontological Arguments.” Stanford Encyclopedia of Philosophy, 2019. https://plato.stanford.edu/entries/ontological-arguments/

Narde, Devonte. “Recent Objections of Ontological Arguments.” Quaerens Deum: The Liberty Undergraduate Journal for Philosophy of Religion 5, no. 1 (2020): 1.

Plantinga, Alvin. The Nature of Necessity. Oxford: Oxford University Press, 1974.

DePoe, John M. “The Heavens Are Declaring the Glory of God: Contemporary Teleological Arguments.” Review and Expositor (Berne) 111, no. 3 (2014): 244–58. https://doi.org/10.1177/0034637314533331.

Swinburne, Richard. The Existence of God. 2nd ed. Oxford: Clarendon, 2004.

Manson, Neil A. “The Fine-Tuning Argument.” Philosophy Compass 4, no. 1 (2009): 271–86. https://doi.org/10.1111/j.1747-9991.2008.00188.x.

Ratzsch, Del, and Jeffrey Koperski. “Teleological Arguments for God’s Existence.” Stanford Encyclopedia of Philosophy, 2019.

Smolin, Lee. The Life of the Cosmos, New York: Oxford University Press, 1999.

Craig, William Lane. “Design and the Anthropic Fine-Tuning of the Universe.” In God and Design: The Teleological Argument and Modern Science. London;: Routledge, 2003. https://doi.org/10.4324/9780203398265.

Collins, Robin. “The Teleological Argument.” In The Rationality of Theism. London: Taylor & Francis Group, 2003. ProQuest Ebook Central.

Friederich, Simon. “Fine-Tuning.” Stanford Encyclopedia of Philosophy, 2017.

J. J. C. Smart, “Laws of Nature and Cosmic Coincidence,” The Philosophical Quarterly 35 (1981): 275–6.

Evans, Stephen C. “The Naïve Teleological Argument.” In Two Dozen (or so) Arguments for God: The Plantinga Project. New York: Oxford University Press, 2018. https://doi.org/10.1093/oso/9780190842215.003.0007

Dawkins, Richard. Blind Watchmaker, New York: Norton, 1987.

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