Thursday, November 15, 2007

An ontological argument

  1. The best accounts of what it is to be a perfection all define perfection in terms of God: e.g., that to be a perfection is to be an intrinsic property of God, or that to have a perfection is to be like God, or that to have a perfection is to be God or to participate in God. (Premise)
  2. Therefore, the true account of what it is to be a perfection defines perfection in terms of God. (Probabilistic inference from 1)
  3. Either there is no definition of God or God is defined in a way dependent on the concept of a perfection (e.g., as the being that has all perfections). (Premise)
  4. If God is defined in terms of perfection, then an account of perfection in terms of being had by God is a circular and (hence) false account. (Premise)
  5. Therefore, God is not defined in a way that is dependent on the concept of a perfection. (By 2 and 4)
  6. Therefore, there is no definition of God. (By 3 and 5)
  7. If x does not exist and has no definition, then an account of a natural (i.e., non-gerrymandered) or ethically significant concept does not involve x. (Premise)
  8. The concept of a perfection is natural or ethically significant. (Premise)
  9. Therefore, if God does not exist, then the true account of what it is to be a perfection does not involve God. (By 6, 7 and 8)
  10. Therefore, God exists. (By 2 and 9)

The best way to challenge this argument is, of course, to come up with an account of perfection that does not involve God. This argument is also closely related to Aquinas' Fourth Way.


Ap said...

I have to say...a lot of your arguments are interesting, new, and sometimes weird.

What's interesting about your argument is that when I think of perfection, I think of capacities or potentialities being actualized. So your argument is good in that traditional thomism is there or at least can taken from it.

But here is an argument against your argument. Perfection is relative to an object, being, or situation. A perfect score in a test is such that there is no question where person S answered wrongly and every question is answered correctly. So..that's one account of perfection that does not involve the definition of God.

Vlastimil Vohánka said...


My thoughts:

It really maters whether I torture a baby (for fun), or not, only if there is a God. The reason for this is that the only live options are theism and naturalism, and on naturalism it doesn't really matter whether I torture a baby (for fun), or not. See my post on this issue at

Could this line of thought be used to support your premise (1)?

David said...

Suppose one takes a standard list of God's perfections: omniscience, omnipotence, omnibenevolence, etc. Then, if one says that God is the only being possessing these perfections, I don't think there is a problem of circularity of the sort you raise. One has characterized God as a being with certain qualities: the definition of each of these qualities isn't dependent on the definition of "perfection". The fact that reference to God is involved in the best account of the concept of perfection doesn't bar a definition of God in terms of qualities that count as perfections under this definition.

Alexander R Pruss said...


I don't know about that. I think the omniproperties aren't going to be a definition, because there is no fact of the matter as to how many and which ones we need to include. They will provide a necessary and sufficient characterization of God, but that's not a definition.

I think I can accept your point, distinguishing between defining God in terms of the concept of perfection and defining God in terms of particular perfections, and do some work to make the argument continue to go through. What I'd have to do is modify (7), removing the "and has no definition", possibly replacing it with something else.


I think the Thomistic picture you're assuming on which goodness is relative to the natural kind is missing a part of the story. Some things are perfections simpliciter, though they are not possible to members of all kinds (and hence the members' not having them is a lack but not an evil). Consider: It is intrinsically good to know the Pythagorean Theorem, and this is good in every kind of being capable of knowing the Pythagorean Theorem (God, angels, and humans). No shark can have this perfection. But if per impossibile a shark had this knowledge, it would be a good thing. On the other hand, some things cannot be good for any being--for instance, the ability to cease to exist with no benefit to any other entity.

I think there is a sense of perfections simpliciter, and the relative perfections of particular species are going to be cases of perfections simpliciter. Perfections simpliciter do not have built-in limitations. For instance, wolves' concrete ability to reproduce have built-in limitations: Wolves do not choose the genes of the offspring, they require pre-existing matter, and they need a co-parent. God doesn't have our concrete ability to reproduce except in virtue of the Incarnation. However, wolves' ability to reproduce is a special case of a perfection simpliciter, namely the ability to produce a wolf, an ability that God has. I am thinking of a perfection simpliciter as something that does not include limitations. For instance, birds have the ability to fly. But that, in my book, involves limitations, and is a special case of the perfection of being able to produce effects at widely disparate locations at times close to each other (a perfection God has in virtue of omnipotence), or maybe it is a special case of the perfection of being able to be present in widely disparate locations at times close to each other (a perfection God has in virtue of omnipresence).

If the Aristotelian has no room for such a notion of perfection that transcends the species, so much the worse for Aristotelianism. But I think there is room for such a thing--one of our grad students, David Alexander, thinks that focal meaning will basically get you that.

David said...

I think the intuitive plausibility of (7) rests on the thought, "an account of a natural concept can't depend on what neither exists nor can be conceptually 'pinned down'." If you want to take (7) so that the difference between giving necessary and sufficient conditions and providing a formal definition matters, then I'm not seeing why one should accept (7). If you modify (7) so that "and has no necessary and sufficient conditions" replaces "and has no definition", then you won't be able to use the modified (7) to prove that God exists.

Alexander R Pruss said...


I do think it's implausible that a natural concept would be defined in terms of a non-existent being, whether definable or not.

Here are two thoughts:

Claim 1: No natural concept is defined in terms of an impossible being.

Claim 2: Either God is indefinable, or God is defined in terms of the concept of perfection, or God is impossible, or God exists.

Claim 1 is plausible. How to argue for Claim 2. Well, I don't have a knock down argument. But suppose the disjunction is false. So, then, God is defined in some way without making use of the concept of perfection. Moreover, he is not impossible and he does not exist. Hence, he contingently fails to exist. Consider some plausible proposal of how God might be defined not in terms of the concept of perfection. Suppose that, say, he is defined as an omniscient, omnipotent, perfectly good creator (oopgc) of everything contingent. Now, if God is a contingent being, it is plausible that there be distinct contingent beings in different worlds, say G1 in w1 and G2 in w2, each of which is an oopgc. I don't have much of an argument for this plausibility claim, but it does seem plausible to me.

Moreover, it seems to me that there could well be infinitely many perfections, going far beyond the perfections of being omniscient, omnipotent, perfectly good and creator. And we have no reason to suppose, unless we think that God exists necessarily, that the oopgc in w1 will have exactly the same perfections as the oopgc in w2.

Another argument. Necessary existence is a perfection. Hence, if God has all perfections, he is either a necessary or an impossible being. But by Claim 1, if we can define perfection in terms of God, God is not an impossible being. Hence, God is a necessary being.