We as Christians have several very convincing arguments for the existence of God. Arguments such as the Kalam Cosmological Argument, the Argument from Design, Argument from the Resurrection of Christ and others are often the forefront of any debate with our atheist friends. One often highly overlooked and rarely used argument is the Modal Ontological Argument.

The reason why the Modal Ontological Argument (from now referred to as the MOA) is rarely used is not because it is in some way flawed or unsubstantiated, but because the concepts it is making use of are often very hard for most people to grasp.

The Craig/Plantinga argument goes like this:

  1. It is possible that God (the Maximally Great Being) exists
  2. If it is possible that God exists, then God exists in some possible worlds
  3. If God exists in some possible worlds, then God exists in all possible worlds
  4. If God exists in all possible worlds, then God exists in the actual world
  5. (C) God therefore exists.

Now, most people when they look at this argument usually “scratch their head and walk away”. The purpose of this article will be to explain the underlying concepts of the argument in the simplest ways possible and then address commonly raised objections, from both people who do not, and those that do understand its concepts.

Firstly, the argument makes extensive use of Modal Logic. In simplest terms, Modal Logic usually deals with possibility, impossibility and necessity of beings. For this purpose, a “being” is simply defined as some conceivable concept, thing or person, whether such a being is possible, impossible or necessary.

To explain this further, in Modal Logic, there exists a semantic of what we would call “possible worlds”. A possible world is simply defined as a conceivable world ruled by the laws of logic. An actual world, the world we live in is also a possible world, it can be conceived and it is ruled by the laws of logic. A possible world is not some universe, region of space or anything like that, although such beings can exist in possible worlds.

To distinct these types of possible worlds, for example, we can conceive of 2 possible worlds.

1.A world in which Donald Trump won the US Presidential Election of 2016

2.A world in which Hillary Clinton won the US Presidential Election of 2016

We know that in the actual world, Donald Trump won the election. However, there is nothing problematic with stating that Hillary Clinton could have won the election and thus in some conceivable world ruled by the laws of logic (possible world) Hillary Clinton HAS won the election.

Keeping all of this in mind, let’s further expound on what kinds of beings we can have in Modal Logic. As hinted above, there exist 3 kinds of such beings:

  1. Impossible beings: These are the beings that could not exist in any possible world. Examples would include square circles, four sided triangles, married bachelors etc. Such beings are plainly illogical and thus could not exist in any possible world.
  1. Possible (or Contingent) beings: These are the beings that could exist in some possible worlds but do not exist in others. Examples would include unicorns, humans, cars, planets etc. We can easily conceive of worlds with or without such beings.
  1. Necessary beings: These are the beings that must exist in every possible world such as for example numbers and mathematical axioms (if they have concrete existence), laws of logic etc.

Anything that could, could not, does or does not exist can be put in these 3 categories. Thus the question arises, in which one do we put God?

God is properly defined as a Maximally Great Being. A Maximally Great Being would be the greatest conceivable being. A Maximally Great Being is an Omnipotent (All Powerful), Omniscient (All Knowing), Morally Perfect being that Necessarily exists.

Now, why would it be the case that if God exists in a single possible world he exists in all of them?

Join me now, in trying to conceive a being that would possess the Maximallity of Great Making Properties, let us try to conceive of THE Maximally Great Being.

We can conceive of a variety of beings in possible worlds, but if we ought conceive of THE Maximally Great Being, we have to assign it certain specific attributes.

It is certainly a great making property to be maximally powerful, as such, a Maximally Great Being, ought have maximal power, that is, Omnipotence.

It is also certainly a great making property to know all things that can possibly be known, as such, a Maximally Great Being, ought have maximal knowledge, that is, Omniscience.

It is also certainly a great making property for one’s nature to represent THE Moral Standard of conduct, as such, a Maximally Great Being, ought be Morally Perfect.

Certainly, all of this is the case, but could we conceive of even a greater being, than the one who possesses these 3 Great Making Properties? Well, we think one can indeed do that.

If we ought talk of a Maximally Great Being, an attribute that one cannot fail to exist would also most certainly be great making. As such, an attribute of Necessity has to be added.

Now, if this is the case, what changes? Well, if there exists, in one possible world, a being that cannot fail to exist, then necessarily, by the implications of its existence in a single possible world, which grants it possibility of existence, such a being has to exist in all possible worlds, as it is necessary. If it failed to exist in all possible worlds, it couldn’t exist in the single possible world we originally conceived of it in, since its attribute of necessity would not be exemplified, and as such we would not have this being. If this being is possible in a single possible world, it means that its attribute, of “cannot fail to exist” is validated, and as such, implies its existence in all possible worlds. (This paragraph is the key to understanding the argument and ought be reread and studied several times).

Of course, if God is not possible, then he cannot exist.

Norman Malcolm correctly stated that God is either Impossible or Necessary. He CAN NOT be simply Possible.

This is thus the very climax of the MOA: You either have to demonstrate that God is Impossible, or accept that God exists, and exists necessarily.

This is therefore the part of the article where we get into objections, both from the scholarly and other, less informed sources.

I will begin by restating what has to be done in order for MOA to fail. One has to demonstrate that a Maximally Great Being (God) is Impossible, that is, refute the first premise. If this cannot be done, premises 2-5 follow necessarily.

Objection #1 “The Reverse MOA”
Some Atheists, sadly, even from the more Philosophical spectrums, have undertaken on themselves to make a caricature out of the MOA by attempting to reverse it against the position of Theism.

Namely, their argument would go like this:

  1. It is possible that God (the Maximally Great Being) does not exist
  2. If it is possible that God does not exist, then God does not exist in some possible worlds
  3. If God does not exist in some possible worlds, then God does not exist in any possible worlds
  4. If God does not exist in any possible worlds, then God does not exist in the actual world
  5. (C) God therefore does not exist

An obvious problem with this argument is in its very first premise. To state that it is possible that God does not exist is to state that in fact, God is illogical.

Why is this the case? Well, to assert that God possibly does not exist in some possible world is to state that the idea of a being that is Necessary, that is, exists in all possible worlds is possibly incoherent. Our Atheist friends however, cannot say that God is incoherent without showing that God actually is incoherent. Thus the entire charade falls apart. Unless the Atheist can demonstrate that God is in some way illogical, he cannot assert that God is possibly incoherent.

To put it in the words of Shaun Doyle of CMI (who wrote an awesome article on the topic,linked bellow): “Many people when they hear “It’s possible that God doesn’t exist” don’t hear what the first premise is actually positing. They hear things like “As far as I know, God might not exist” or “God could’ve existed, but doesn’t actually exist”. Neither of these are right; the first is an issue of what we know, not an issue of what’s really possible, and the second makes God out to be a contingent being, which is nonsense. Rather, it’s asserting that ‘God’ possibly can’t exist, like how we could assert that ‘married bachelors’ possibly can’t exist. Remember that part of the definition of ‘God’ these arguments work with is that ‘God’ cannot fail to exist. In other words, the first premise isn’t simply asserting the idea that God might exist, but doesn’t actually exist; it’s asserting that the concept of God is possibly incoherent.” (1)

It has in fact been shown that “maximal greatness” is in fact a possible property. This provides basis for the first premise of the Modal Ontological Argument and thus shows that premise 2 of the reverse is at best baseless. Philosopher Robert Maydole developed an ontological argument in 2003 to demonstrate the possibility of the property of maximal greatness. It is quite a complex modal proof. There are three premises to the Modal Perfection Argument:

M1 A property is a perfection only if its negation is not a perfection.

M2 Perfections entail only perfections.

M3 The property of being supreme is a perfection.

(The defense of the argument is rather complex and out of the scopes of this article, links are provided below to Maydole’s work) (*)

Objection #2 “The Omnipotence Paradox”

The basic purpose of the argument is to attack the possibility premise of the MOA. It attempts to show that the very idea of God is incoherent and thus is not to be regarded as possible in any possible world.

There are many different forms this argument can take. A common one would be to state that God is Omnipotent and Morally Perfect. So if God can do all things and yet is Morally Perfect, can he perform evil actions? If he can then he is not Morally Perfect. If he cannot he is not Omnipotent. Without either of these, he is not God.

The problem with this argument is improper defining of Omnipotence. An Atheist would simply define Omnipotence as someone “being able to do everything”. This, however is a very simplistic and incorrect definition and it presents a strawman.

Now, the theistic definition of Omnipotence is “being capable of bringing about all logically possible states of affairs.”

Now then, let us give a task to being some Omnipotent being B to, by its Omnipotence make the  Maximally Great Being (for these purposes let’s name this being A) perform a Morally Imperfect action.

Is such logically possible?

It would be a logically impossible state of affairs for a Morally Perfect Being to Perform a Morally Imperfect action, regardless of what potency might try to make it happen, it is just nonsense.

As such, a Morally Imperfect action being unable to be performed by an MGB is not a detriment to its Omnipotence, since no potency is capable of bringing about a state of affairs such that a Morally Perfect Being performs a Morally Imperfect action.

But a smart atheist might say that this is surely not the case. Being B, that is not morally perfect could conceivably for example, torture a child simply for fun, while Being A, since it is Morally Perfect, cannot do that, as such, Being B is more potent than Being A.

This however, is false. Let us conceive of 4 scenarios.

S1: A can make B do an imperfect action

S2: B can make B do an imperfect action

S3: B cannot make A do an imperfect action

S4: A cannot make A do an imperfect action

So as we see, B is in no scenario more potent than A, even though B can itself perform something morally imperfect, it is incapable of making a Morally Perfect being do such a thing itself. A on the other hand, with its Omnipotence, faces no issues in making B do an imperfect action, if that be A’s will, since B is not a morally perfect being by definition.

Thus, by the proper definition of Omnipotence, such arguments are shown to be inapplicable, while our Atheist friends demonstrate that they argue without even knowing the basic definitions that are in use, at the very core of the argument.

Objection #3 “Goldbach’s Conjecture Argument”

Some have attempted to parody the argument by “solving” mathematical problems using the form of the MOA.

The Goldbach’s Conjecture states that: “Every even integer greater than 2 can be expressed as the sum of two primes.”

So they would make an argument in this form:

  1. It is possible that Goldbach’s Conjecture is true
  2. If it is possible that Gold. Conj. is true then Gold. Conj. is true in some possible worlds
  3. If Gold. Conj. is true in some possible worlds then Gold. Conj. is true in all possible worlds

4.If Gold Conj. is true in all possible worlds then Gold. Conj. is true in the actual world

5.(C) Therefore Goldbach’s Conjecture is true

Since Goldbach’s Conjecture is a mathematical problem, it is like God, either Necessary or Impossible. If it is true in one world, it is true in all of them.

This however is a nonsensical presentation as we do not have any sort of a way in which we could test the possibility of Goldbach’s Conjecture as Goldbach’s Conjecture is an infinite set of numbers. To the contrary, we can examine if ontological properties of God (Omnipotence, Omniscience etc.) are possible.

The argument therefore, is absolutely useless against the MOA.

Objection #4 “The Maximally Great Pizza”

Some less scholarly Atheists have attempted to state that we could substitute God for a Maximally Great Pizza (or whatever other physical thing might come to your mind) and as such demonstrate the ludicrousness of the MOA.

This however, as previously explained is nonsensical, as pizzas are Contingent, not Necessary beings.

What would make a Pizza maximally great? Is Pizza an all knowing all powerful person? Couldn’t we always conceive of a Pizza that has one more pepperoni on it? If so, how can a Pizza be defined as maximally great?

Objection #5 “The Logical Problem of Evil”

Atheists would attempt to state that God’s existence is impossible since evil exists. They would form an argument in this form:

1.If an Omnipotent, Omniscient, and Omnibenevolent (All Good) God exists, then evil does not.

2.There is evil in the world.

3.Therefore, an Omnipotent, Omniscient, and Omnibenevolent God does not exist.

They would attempt to say that if God is good, perfectly good, and omnipotent then he would not allow for evil to exist. If he does allow for evil to exist but is Omnipotent, he is not good. If he is good but not Omnipotent, how is he God? If he is neither why call him God?

There are 3 avenues of attack against this argument:

1.The basis of Objective Morality

2.Omniscience Defense

3.Free Will Defense

1.The basis of Objective Morality

The Atheist has to assume that God exists in order to argue that he does not. Why is this the case? The Atheist assumes the existence of Objective Moral Values by which he would judge if God’s actions, or actions he allows are evil or not. If he does not have an objective standard, this argument is nonsensical.

An Atheist cannot have an Objective Moral Standard without such a standard being based on the perfect, eternal and unchanging nature of God. In any other case it is simply subjective.

If he argues that no Objective Morals exist (he would be wrong) but for the purpose of this argument, he just sealed its fate.

  1. Omniscience Defense

God is by definition Omniscient. Humans are not. It is impossible for a human to examine all the various reasons as to why God would have allowed evil and since “Evil Exists” and “God Exists” are not explicitly logically contradictory statements, one cannot thus propose that the existence of evil would be contrary to the existence of God.

     3.The Free Will Defense

Dr. Alvin Plantinga would argue that God would have a sufficient reason to allow evil to exist since free will of human agents is valuable.

“God’s creation of persons with morally significant free will is something of tremendous value. God could not eliminate much of the evil and suffering in this world without thereby eliminating the greater good of having created persons with free will with whom he could have relationships and who are able to love one another and do good deeds.” (2)

Plantinga pointed out that God, though omnipotent, could not be expected to do literally anything. God could not, for example, create square circles, act contrary to his nature, or, more relevantly, create beings with free will that would never choose evil. Taking this latter point further, Plantinga argued that the moral value of human free will is a credible offsetting justification that God could have as a morally justified reason for permitting the existence of evil. (3) (4)

Dr. Plantinga argues for this position in much more detail than I could do justice in this article so for further detail on the argument, one can refer to his book “God, Freedom and Evil”.

Most contemporary philosophers consider his argument successful in dealing with The Logical Problem of Evil.

Getting into the only objections I would actually consider serious , the one proposed by Dr. Peter van Inwagen (who is actually a Christian Philosopher) we would get the “Correct Atheist Argument”.

Objection #6 “The Correct Atheist Argument (Modal Knowno)”

To counter the Modal Ontological Argument Dr. Inwagen would propose that there possibly exists a being that he would call a Modal Knowno. A Modal Knowno is a being that knows no God exists.

His argument would go like this:

  1. It is possible that a Modal Knowno exists

     2.If it is possible that a Modal Knowno exists in a single possible world, then God does not exist in that possible world

    3.If God does not exist in a single possible world God is Impossible

    4.(C) Therefore God is Impossible

Dr. Inwagen would further argue that since both God and a Modal Knowno are equally as possible, the MOA is not to be used as a serious argument for either the Atheist or the Theist position.

However, there are several problems with Dr. Inwagen’s argument in this case.

When speaking of possibility in the first premise of these arguments we are speaking of 2 kinds of possibilities.

  1. Purely Logical possibility
  2. Metaphysical possibility

Logical possibility would be simply examining if something makes logical sense, while Metaphysical possibility is regarded as something making logical sense, in addition to also having some other reasons for thinking it is possible.

In my defense I am going to attack the possibility of the Modal Knowno on both of these bases.

Firstly, when considering both God and the Modal Knowno on the basis of Metaphysical Possibility, the existence of God is possible from various arguments for his existence such as the Kalam Argument, Moral Argument, The Teleological Argument, Argument from the Resurrection of Jesus etc.

The Modal Knowno enjoys no such Metaphysical support.

Modal Knowno is also a very Metaphysically problematic concept. How would a being know that God does not exist if God is not an illogical concept? The Atheist would pretty much have to give the Modal Knowno the property of Omniscience in order for this to be the case, in which case this would turn into a very funny charade.

In conclusion, purely on the Metaphysical basis, God is possible while the Modal Knowno is not.

The Modal Knowno however faces other problems, namely on the purely Logical basis.

When putting God and the Modal Knowno side by side and intuitively examining the possibility of their natures, the theistic confidence in God’s possibility is based upon the intuitive coherence of maximal greatness, considered in and of itself. He then INFERS that a world with a Modal Knowno is impossible.

When examining the nature of a Modal Knowno in and of itself, the possibility of its nature ASSUMES the incoherence of maximal greatness.

In other words, when looking purely at the nature of each of these beings in and of themselves, from God’s nature, which just by its properties does not assume anything, we can conclude that a Modal Knowno is impossible since this nature does make perfect sense.

However, when looking purely at the nature of a Modal Knowno, such a being, even in its own name has a property of knowing God does not exist, and thus for its possibility, it assumes that God cannot exist.

In conclusion the Modal Knowno fails to be possible on both the purely Logical and the Metaphysical bases and as such is not to be used as an argument against the MOA.

An examination in this manner is to be used against any other form of the Correct Atheist Argument (such as the world with only one particle, a world without sentient beings etc.)

In the conclusion to the article, The Modal Ontological Argument has stood the test of time against various attacks from various atheologians and philosophers and has firmly established itself as perhaps the most powerful argument in the theistic inventory.

Objection #7 “Next to Maximally Great Beings”

This objection can be validly sorted into the previous one, however, I’ll, for the purposes of this article, give it a more detailed treatment.

In my debates on the subject with Atheists I engaged, some would propose a being that exemplifies some Great Making Properties, but not all of them, and as such be contradictory to the existence of a Maximally Great Being. Why? Because a Maximally Great Being, would be one that is an originator to all other beings.

If there for example, exists a being such as a Highly Potent, Highly Knowing, Morally Perfect and Necessary being, then this being would conceivably be contradictory to the existence of God, even though it would have the same metaphysical reasons to be considered possible, as God (An Omnipotent and Omniscient being is a perfectly possible candidate for the creation of the Universe, Resurrection of Christ, Design of the Universe, Uncanny Efficiency of Mathematics and so forth)

The problem however with this argumentation is manifold. Firstly, the Atheist gives us essentially 2 possibilities, either that God exists, or that a being that explains the origin of the Universe, Resurrection of Christ and so forth exists. Two possibilities that are very problematic for atheism. Of course, an Atheist might propose that the third option is that neither exists, but he would have to demonstrate their logical incoherence, which cannot be done.

As such, at best, we are left with either a possibility of God being the explanation of these facts about our world, or a being with attributes closely aligned to that of God.

But would this really work? It seems to us possible, that potency can be exemplified to its highest order, that is, Omnipotence.

And it seems rather possible also, that knowledge can be exemplified to its highest order, Omniscience.

Why would it be the case that a being cannot have them, and then other attributes of this lesser being? No good argument can be brought forth against these individual attributes.

Therefore, in even still, further consideration of the facts about say, the Resurrection of Christ and the Christian faith, one can with certainty decide between the 2, similar albeit quite different options, in that the God who raised Christ certainly claims to be both Omnipotent and Omniscient, and that we have no reasons to consider either attribute impossible in combination with the rest.

In conclusion, the MOA has been thoroughly defended and objected to by the greatest philosophers of our time, the conclusion however, still remains quite unchanged. If God is possible, he exists.

If you cannot demonstrate that God is impossible, why do you reject his existence?

Many thanks to Timothy Bukowski for his help in writing the article.

May the Triune God be praised in all that we do.


(1) https://creation.com/reverse-ontological-argument

(2) http://www.iep.utm.edu/evil-log/

(3) Plantinga, Alvin (1977). God, Freedom, and Evil. Grand Rapids, MI:: Eerdmans. pp. Chapter 4

(4) “Evil and Omnipotence”. Mind. 64 (210): 455–465.

(*) https://www.pdcnet.org/philo/content/philo_2003_0006_0002_0299_0313