the ontological argument

This tag is associated with 4 posts

Really Recommended Posts 8/19/16- singing the Psalms, the Ontological Argument, and more!

snowl-owl-post-arpingstoneHello friends! Another week has passed and it’s time to kick back on Friday and relax with some Really Recommended Posts that I’ve collected for your perusal. This edition is a snowy owl edition for two reasons. 1) New Harry Potter Book (check out my post on it here); 2) hopefully it will bring in colder weather. By the way, if you ever have suggestions for future Really Recommended Posts, let me know!

The Ontological Argument– check out this page and video from William Lane Craig at Reasonable Faith that gives the basics of the ontological argument. Be sure to also check out my own posts on the topic.

Response to Peter Jones on “Conservative Moms” and “Stunted Masculinity”– Here’s a thoughtful response to a surprising accusation from a pastor who argues for men leading in the home. His argument is basically that, despite doing everything right, “conservative moms” are the ones responsible for “stunted masculinity” that comes from their male children.

“You Lift My Head” based on Psalm 3– A frankly beautiful song that is based on a Psalm. Overview Bible is also going through all the Psalms to try to make a hymnbook that includes every single one. Check it out and follow this excellent site.

A 60,000 Year Varve Record from Japan Refutes the Young-Earth Interpretation of Earth’s History– Did you know that varves, tree rings, and radiocarbon dating align on coming up with dates? It’s awfully hard to just dismiss this kind of interwoven evidence. How could they line up if they are are faulty ways to date the age of the Earth?

Really Recommended Posts 10/9/15- Gospels, Domestic Abuse, Dinosaurs, and more!

postI am pleased to present this wide range of topics to you, dear readers! I hope you enjoy the reads as much as I did. We have posts on the origins of the Gospels from an atheistic perspective, domestic abuse, the ontological argument, soft tissue in dinosaurs, and Bill Nye on abortion. Let me know what you think, and be sure to thank the authors as well!

Where the Gospels Came From– This is a satirical post that highlights how broad swaths of internet atheism tend to view the origin of the Gospels. It’s well worth reading as it highlights some of the major errors.

When Staying in an Abusive Relationship is Part of Your Theology– It is Domestic Violence Awareness Month, and this post from Christians for Biblical Equality highlights one major difficulty with some theologies- they argue that one should stay in an abusive relationship from theological reasons.

The Probability of God’s Existence is Either 0% or 100% (video)– Kenneth Keathley offers this analysis and presentation of Alvin Plantinga’s ontological argument. He defines terms and answers some major objections, with the objections offered by atheists themselves.

“Soft Tissue” Found in Dinosaur Bones– Creationists sometimes claim that the finds of “soft tissue” undermine the possibility for an old earth perspective. Is that the case? Here is some analysis of this claim and some more recent findings regarding allegations of blood and other soft tissue found in ancient fossils.

Responding to Bill Nye’s Abortion Video– Bill Nye “The Science Guy” made a lot of claims about science and abortion in a video recently. Here’s a thorough analysis and refutation of his claims.

Quick Links: Craig on the Ontological Argument

A common objection to the ontological argument for the existence of God is that existence is not a property. People often misunderstand that modern versions of the argument don’t rely on making existence a property, but upon the idea that necessary existence is greater than contingent existence. William Lane Craig has some clarifying comments on the ontological argument in response to two questions regarding this confusion:  here.

The Ontological Argument: Question Begging?

Is the ontological argument question begging? Short answer: some versions yes, others, no. For the long answer, read on:

Many versions of the ontological argument appear to beg the question. The Anselmian version of the argument seems invalid, but there are other formulations of it which avoid its invalidity (cf. Maydole’s chapter on the Ontological Argument in The Blackwell Companion to Natural Theology, eds. Craig + Moreland, 553ff). Then, Alvin Plantinga came along and introduced the modal ontological argument, which relies on S5 modal logic. I have discussed Plantinga’s argument elsewhere, as well as demonstrated its validity.

Therefore, we will focus on a new considerations. Consider the following very simple version of the modal ontological argument:

1) Possibly, God necessarily exists

2) Therefore, God necessarily exists

The argument seems, at first face, to be a very strange argument. However, the argument does not beg the question when viewed through modal logic. 1) does follow from 2) in a non-tautological way, but 1) must be established.

Symbolically, the argument is written as the following (Take “T” to be “God exists”):

1) ◊□T

2) □T

S5 modal logic is based upon this very axiom. Namely, ◊□x⊃□x or  ◊□x iff □x (Hughes & Cressewell, A New Introduction to Modal Logic, 58). For in modal logic:

3) that which is “possible” exists in “some possible world.”

4) That which is necessary exists in all possible worlds

Therefore, if something is possibly necessary, then it must obtain in some possible world (3). however, if it is necessary, then it exists in all possible worlds (4). Therefore, if something is possibly (exists in some possible world) necessary (exists in all possible worlds), then it exists in all possible worlds.

Is this argument question begging? If it is, then it is not obviously so. Alexander Pruss has argued out that the argument is question begging only if it is directed at one who does not understand that 1) entails 2) (Pruss, The Principle of Sufficient Reason, 232). I’m not convinced that this is correct. Soundness of arguments don’t depend upon whether people understand them–they depend on whether they are valid or true.  However, it seems Pruss has an intuitive point here, in that even if this argument isn’t question begging, it appears to be.

How might the theist respond? Well, Pruss argues that if the theist argues for the establishment of S5, then it is no longer question begging (232). Alvin Plantinga does just that in God, Freedom, and Evil, as Pruss points out. We’ve already established elsewhere that Plantinga’s argument doesn’t beg the question regardless (see here), but this symbolic proof is bolstered by providing an argument for S5.

Then, it seems to be the case that if S5 modality is valid, God necessarily exists.

Are there versions of the ontological argument that resist this reduction to the “simplistic” version offered here? Yes, there are.  For example, Stephen Parrish’s ontological argument:

5) The concept of the GPB (Greatest Possible Being) is coherent (and thus broadly logically possible)

6) Necessarily, a being who is the GPB is necessarily existent, and would have (at least) omnipotence, omniscience, and moral perfection essentially.

7) If the concept of the GPB is coherent, then it exists in all possible worlds.

8 ) But if it exists in all possible worlds, then it exists in the actual world.

9) The GPB exists (Parrish, God and Necessity, 82)

This argument may initially seem to be susceptible to the same reduction, but it can avoid this reduction by lengthening it to:

10) the GPB is coherent (and logically possible)

11) the GPB’s coherence entails modal possibility

12) the GPB is necessary

13) modally, if something is possibly necessary, then it is necessary

14) the GPB exists necessarily

The key premise here is 10), because if it is true, then the rest of the argument follows necessarily. What reasons do we have for thinking 10) is true? Such a debate is beyond the scope of this post (good discussions can be found throughout theistic philosophy of religion–see, in particular, Craig and Moreland, Philosophical Foundations for a Christian Worldview and Swinburne, The Coherence of Theism; see also my brief discussion in the post on the argument here); but it seems to me that there is no incoherence in the concept. If that is the case, then I am justified in holding 14).

Therefore, it seems the modal ontological argument is not question begging, particularly if one argues first for the validity of S5 modality. Furthermore, there are other modal arguments which don’t rely on a reduction to a simple modal argument. For example, Parrish’s ontological argument relies instead upon the coherence of the GPB. Such arguments are successful if arguments against the GPB’s coherence are shown to be unsuccessful. In either case, God exists.

Ergo deus est.



Maydole, Robert E. “The Ontological Argument.” The Blackwell Companion to Natural Theology. Edited William Lane Craig and J.P. Moreland. Blackwell, 2009.

Parrish, Stephen E. God and Necessity. University Press of America. 1997.

Pruss, Alexander. The Principle of Sufficient Reason. Cambridge. 2006.


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