The ontological argument for the existence of God is one of the few arguments originating in logic rather than observation. Teleological and cosmological arguments, for instance, demonstrate how the existence of God best explains apparent design in nature and the nature of causality, respectively. In contrast, the ontological argument relies on pure reasoning. The argument has both strengths and weaknesses. Few consider the ontological argument convincing, even among Christian believers. Carefully considering it does, however, lead to ideas that strongly support the existence of God.
The ontological argument has been phrased in many ways. The most well-known comes from Anselm in the eleventh century. The core of Anselm’s position is that God is “a being than which no greater can be conceived.” According to Anselm, existing is “greater than” not existing; therefore, God must exist as the “greatest” thing of which one can conceive. In somewhat plainer language, Anselm suggested that God is the “best” thing possible, and to exist is “better” than to not exist; therefore, God must exist.
Those who encounter the ontological argument for the first time typically react in one of two ways. For some, it’s abstract enough that it makes no sense. Most others find it unconvincing, whether or not they can articulate a specific reason. A few people find it compelling, perhaps after long study, but this is not a common response. Even those who reject it, however, have a difficult time explaining exactly why it is wrong.
The main drawback of the ontological argument is logical: it’s not clear how concepts such as “greatness” and “existence” apply in a purely logical setting. It would be circular and illogical to simply say, “God by definition exists; therefore, He exists.” Still, adding the stipulation that God is the “greatest possible” being doesn’t seem to do much to break that circle. Further, problems such as the liar’s paradox prove that logic can form irrelevant loops: statements that are self-contained and not meaningful in reality.
Most who reject ontological arguments do so for that reason, even if they can’t articulate why. It simply “feels” wrong; our rational instincts react against the idea of simply defining something to exist. For most people, non-believers in particular, the ontological argument carries little impact.
And yet the ontological argument has not completely faded and disappeared. In part, that’s because, the more closely one tries to define its terms, the more the biblical God emerges. Two points summarize why this is the case: the attributes of God and the concept of objective truth.
Efforts to debunk the ontological argument sometimes apply it to a different object or idea to show the structure is absurd. A common example is to posit a “perfect island”: since existing would be “more perfect” than not existing, this island must exist somewhere. That’s clearly not true, in practice, but not for the reasons the skeptic assumes. The problem there is that the term island itself expresses limits. Anything called an “island” must be finite and limited. Sooner or later, ideas like “perfection” or “greatness” contradict the requirements of calling something an “island.”
God, however, does have the ability to fully meet the definition of an “absolutely great” or “absolutely perfect” thing. That’s because all God’s attributes are equally perfect. An island can’t be omniscient, by definition, but God can be—and only because He is also omnipotent and omnipresent. If we stretch the definition of island so it can become as “perfect” as anything can be, it winds up becoming all-powerful, all-wise, and all-present—which means it would be God. In an effort to debunk the ontological argument, one winds up repeating it: the greatest conceivable thing must exist, by definition.
The other reason the ontological argument clings to life is the idea of objective truth. Concepts such as power, knowledge, goodness, and so forth assume there is some standard by which to judge those ideas. We don’t measure distances or weights against “infinite distance” or “infinite weight,” since infinity doesn’t literally exist and, even if it did, there’s no way to measure something against infinity. Yet we instinctively realize that things like power and morality are real and make sense only in respect to some absolute standard. Claiming otherwise is self-defeating: “subjective morality” is virtually a contradiction in terms. We’re inevitably pressed to recognize the existence of absolute benchmarks for those ideas.
Notice, however, what that statement entails. If there is an absolute measure of goodness, then—forgive the awkward grammar—the “most good” thing must exist. The same is true of power, knowledge, etc. Once again, this turns into a re-statement of the ontological argument: there must be something in existence than which no greater or more perfect thing can be conceived. That we have standards for morality, etc., suggests something very close to the premises of the ontological argument. It also implies there is only one being for whom the argument would work, anyway: one being ultimately perfect in every possible way—and that being would be God.
The ontological argument is neither as powerful nor as useless as extreme views might suggest. It has little practical value, especially for skeptics or non-believers. Like Pascal’s Wager, the ontological argument sometimes gets a bad rap: it’s not simplistically arguing that “conceiving” of something is sufficient to make it real. However, the more one tries to untangle it, the more the ontological argument digs in and refuses to be disproved.
It’s much easier to say, “The ontological argument doesn’t work for me,” than it is to say, “The ontological argument is false because—.” It’s an interesting example of arguments for God’s existence, and an important one, even if it’s not held in high regard by many people.