CHAPTER 5: The Ontological Argument
CHAPTER FIVE
THE ONTOLOGICAL ARGUMENT
Discovered by St. Anselm in the 11th century, the ontological argument has been reformulated and defended by contemporary philosophers such as Alvin Plantinga, Robert May-dole, Brian Leftow, and others. Let’s consider the version formulated by one of the argument’s most eminent defenders, Alvin Plantinga. In order to grasp Plantinga’s version of the argument, we need to have some understanding of the notion of a “possible world.”
By a “possible world” one doesn’t mean a planet or even a universe; rather, we mean a complete description of reality, or a way reality might be.
By a “possible world” one doesn’t mean a planet or even a universe; rather, we mean a complete description of reality, or a way reality might be. Perhaps the best way to think of a possible world is as a huge conjunction, whose individual conjuncts are various descriptive statements. A possible world is a conjunction that includes every statement or its negation, so that it yields a complete description of reality—nothing is left out of such a description. To say that God exists in some possible world is just to say that there is a possible description of reality that includes the statement “God exists” as part of that description.
Now in his version of the argument, Plantinga conceives of God as a being that is “maximally excellent” in every possible world. Plantinga takes maximal excellence to include such properties as omniscience, omnipotence, and moral perfection. A being that has maximal excellence in every possible world would have what Plant-inga calls “maximal greatness.”
THE ONTOLOGICAL ARGUMENT: A SIMPLE FORMULATION
What shall we make of this argument?
It might surprise you to learn that premises 2 through 4 of this argument are relatively uncontroversial. Most philosophers would therefore agree that if God’s existence is even possible, then He must exist. The principal issue to be settled with respect to Plant-inga’s ontological argument is what reason exists for thinking that the key premise, It is possible that a maximally great being (God) exists, is true.
Premise 1: It is possible that a maximally great being (God) exists.
The idea of a maximally great being is intuitively a coherent idea, and so it seems plausible that such a being could exist. In order for the ontological argument to fail, the concept of a maximally great being must be incoherent, like the concept of a married bachelor or a round square. But the concept of a maximally great being doesn’t seem even remotely incoherent; on the contrary, it seems perfectly coherent. This provides prima facie warrant for thinking that it is possible that a maximally great being exists.
For the ontological argument to fail, the concept of a maximally great being must be incoherent.
But won’t this appeal to intuition lead to a sort of overkill? One of the most important strategies employed by detractors of the ontological argument has been the construction of parodies of the argument. By showing that analogous notions like that of “a most perfect island” or “a necessarily existent lion” also seem prima facie to be coherent concepts, critics have tried to show that one is forced by the logic of the argument to postulate the existence of all sorts of ridiculous beings.
A maximally excellent being, if it is immaterial, could transcend such physical limitations and so be conceived as necessarily existent.
But the argument’s defender may plausibly maintain that the idea of God differs crucially from supposedly parallel notions traditionally put forward by the argument’s detractors. For one thing, the properties that go to make up maximal excellence as Plantinga defines it have intrinsic maximum values, whereas the excellent-making properties of things like islands do not. For example, omniscience is the property of knowing only and all truths; it’s impossible to know any more truths than that. By contrast, in the case of islands, there could always be more palm trees or native dancing girls; therefore, there cannot be a most perfect or greatest conceivable island. Moreover, it is far from clear that there even are objective excellent-making properties of things like islands, for the excellence of islands seems to be relative to one’s interests—does one prefer a desert island, or an island boasting the finest resort hotels?
The idea of something like a necessarily existent lion also seems incoherent. As a necessary being, such a beast would have to exist in every possible world we can conceive. But any animal which could exist in a possible world in which the universe is composed wholly of a singularity of infinite space-time curvature, density, and temperature just is not a lion. By contrast, a maximally excellent being, if it is immaterial, could transcend such physical limitations and so be conceived as necessarily existent.
Moreover, we also have independent grounds for affirming the truth of premise 1. Other theistic arguments like the cosmological argument and the moral argument may lead us to think that it is plausible that a maximally great being exists. The cosmological argument issues in a necessary being—a being that exists in every possible world—as the explanation of why anything at all exists. Similarly, the moral argument yields a necessarily existing being as the ground of moral values and duties, some of which hold necessarily, in every possible world. Therefore, the cosmological argument leads to a metaphysically necessary being which is the ground of existence for any concrete reality, and the moral argument to a paradigm of moral value which must be as metaphysically necessary as the moral values it grounds. On the basis of considerations like these, we might well consider ourselves to be warranted in believing that it is possible that a maximally great being exists.
The question that arises at this point is whether the ontological argument has not become question-begging. An argument is question-begging if one’s only reason for accepting a premise in the argument is that one already accepts the conclusion, so that one in effect reasons in a circle. In the present case, it might seem that the reason one thinks that it is possible that a maximally great being exists is that one has good reasons to think that a maximally great being does exist.
An argument is question-begging if one’s only reason for accepting a premise in the argument is that one already accepts the conclusion.
But this misgiving may arise as a result of thinking of the project of natural theology in too linear a fashion. The theistic arguments need not be taken as links in a chain, where one link follows another so that the chain is only as strong as its weakest link; rather, they are like links in a coat of chain-mail, in which all the links reinforce one another so that the strength of the whole exceeds that of any single link. The ontological argument might play its part in a cumulative case for God’s existence, in which a multitude of factors simultaneously conspire to lead one to the conclusion that God exists. Anselm was perhaps wrong in thinking that he had discovered a single argument which, standing independently of all the rest, served to demonstrate God’s existence in all His greatness. Nevertheless, his argument does encapsulate the thrust of all the arguments together to show that God, the Supreme Being, exists.