Up until this point, we have been laying the ground work for the ontological argument without really knowing how it all contributes to the outcome of God’s existence. In this blog, we will actually set out the argument and consider some initial objections.

“God” in the Ontological Argument

Because of the limitations of natural theology, the word “God” does not refer to any particular deity in any religion. In addition, as far as the ontological argument is concerned, it is actually more helpful to re-identify God as a “maximally great being.” This maximally great being is one who possesses all great-making properties to the highest degree in every possible world (this definition will be explored later in greater detail). With the necessary framework in place, we are now ready to look at the premises of the modal ontological argument in a formal arrangement:

• It is possible that a maximally great being exists.
• If it is possible that a maximally great being exists, then this being exists in some possible world.
• If a maximally great being exists in some possible world, then this being exists in every possible world.
• If a maximally great being exists in every possible world, then this being exists in the actual world.
• If a maximally great being exists in the actual world, then a maximally great being exists.
• Therefore, a maximally great being exists. [1]

Ignoring for a moment whether or not you think the argument is ridiculous, it is at least easy to see that the argument is logically valid. That is, one can see that the conclusion follows inescapably from the other premises. Since the argument is logically valid, the only other condition that must be met for it to be sound is that the premises be true. This being the case, we will turn our attention to one of the more difficult premises.

If in One, Then in All?

At first glance, there seems to be something self-serving or contrived about premise 3: If a maximally great being exists in some possible world, then this being exists in every possible world. To help work through this obstacle, recall the equation we used last time to aid our thinking about epistemic and metaphysical possibility: (√784 – 18)² = 3⁴ + 19. Mathematical equations, because of the nature, are either necessary or impossible – they are either true in every possible world or no possible world. To help yourself out, you can plug this particular equation into a calculator and see for yourself that the equation really is true. Knowing that the equation is true, we can use it in a sort of round-about way to illustrate what is going on with premise 3. Using the structure of the ontological argument, consider this example:

• It is possible that (√784 – 18)² = 3⁴ + 19 is true. (Remember, “possible” means actually, metaphysically possible, not epistemically possible for all we know.)
• If it is possible that (√784 – 18)² = 3⁴ + 19 is true, then this equation is true in some possible world.
• If (√784 – 18)² = 3⁴ + 19 is true in some possible world, then this equation is true in every possible world.
• If (√784 – 18)² = 3⁴ + 19 is true in every possible world, then this equation is true in the actual world.
• If (√784 – 18)² = 3⁴ + 19 is true in the actual world, then this equation is true.
• Therefore, this equation is true.

When this equation is used in the argument instead of a maximally great being, premise 3 becomes much less controversial. This is because we already know that true mathematical equations are the kinds of things that are necessary. In the same way, a maximally great being is one, by its very nature, that is also necessary. Think, which being would be greater: The one who is responsible for the creation of a single possible world, or the one who is responsible for the creation of a hundred possible worlds? Clearly, the maximally great being would be responsible for the creation of every possible world. By definition, therefore, a maximally great being is one who exists in every possible world. And if this being did not exist in every possible world, then he would not be maximally great.

Conclusion

Making the jump from a possible world to the actual world is not as far-fetched as one might first imagine. It works perfectly fine when applied to true mathematical equations because those are the kinds of things that are necessary. The claim, therefore, is that a maximally great being is also the kind of thing that is necessary. It seems easy to show that such a being would have to be necessary if his existence were possible, and so the possibility of this being’s existence will be explored in-depth in the coming blogs.

[1] Craig, William Lane. Reasonable Faith: Christian Truth and Apologetics, third edition, p. 184-85.