Saturday, January 01, 2022

Peter van Inwagen and Anselm's Ontological Argument/Descartes (In Progress)

In the fourth edition of his highly acclaimed Metaphysics, Peter van Inwagen reviews the ontological argument set forth by Anselm of Canterbury: he explains that Anselm evidently thought atheism or the utterance of atheistic statements makes the atheologian produce formal contradictions. Now contradictions may be implicit or explicit: an explicit contradiction would be "It is snowing and it is not snowing," assuming the speaker had the same referent in mind for "snow" and other qualifications were met. Another example is "That object is a square and that object is a circle." Both utterances are blatant contradictions given the fundamental assumptions for traditional western logic, and for that reason, they're both necessarily false. Logicians also label contradictions as logically impossible statements--they are incoherent as well as Richard Swinburne notes. Should one view the profession of atheism in a similar light? Are statements about the nonexistence of God inherently contradictory? That is the way van Inwagen seems to interpret Anselm's ontological argument: atheism ostensibly entails an explicit contradiction. But the reader should not assume that van Inwagen necessarily agrees with this ostensible entailment.

Van Inwagen builds on the points outlined above; he contends that Anselm's ontological argument possibly addresses the question, why should there be anything at all? He then poses a conditional proposition, namely, if Anselm logically demonstrates that God necessarily exists, then he establishes that there must be something that exists (i.e., there cannot be nothing). While the ontological argument does not prove that this cosmos must exist, it indicates that something must obtain (pp. 129-130). However, two monks (Gaunilo and philosopher-theologian Thomas Aquinas) have resisted this argument. So has philosopher Arthur Schopenhauer and astrophysicist Paul Davies. Therefore, to simplify the discussion, van Inwagen leaves Anselm in order to discuss the ontological argument devised by Rene Descartes, the French philosopher and mathematician (1596-1650 CE). I must admit that the move is a curious one to me but I will not demur: van Inwagen reckons that the Cartesian version is easier to state and follow. Why not start with it at first?

Like its argumentational predecessors, some philosophers accuse the Cartesian ontological argument of being faulty, invalid, or possibly absurd. Immanuel Kant decided to challenge the argument by noting that it assumes existence is a real predicate which can be added to other properties that characterize a thing (i.e., it can be attributed to a subject). However, Kant maintains that existence is a conceptual predicate: by using the reckoning of Kant, van Inwagen demonstrates why opponents of the ontological argument might think the argument is incoherent, absurd or invalid. He wields the example of someone pitting existent Homer (the Ionian poet) against non-existent Homer (the non-existent version of the Ionian): another work sets forth the example of existent versus non-existent steak. Or what about imputing existence to things we know do not exist, like unicorns? Such arguments have ruled the day until now, but van Inwagen accuses such philosophical objections of concentrating on the periphery of the ontological argument instead of its center (p. 132).

To show the potential difficulty with Kantian thinking, Metaphysics introduces the concept of necessary existence. For the sake of parsimony, let's define a necessary being as an entity that obtains in all possible worlds; regardless of the possible world under consideration, a necessary being would exist in it. Another denotation of "necessary being" is that such an entity must exist or obtain (it cannot not exist). A necessary being is not contingent upon anything or anyone: it existence is a se, not ab alio. Furthermore, the non-existence of a necessary being is just as impossible as a round square, square circles, a four-sided Euclidean triangle or a married bachelor.

Armed with the concept of necessary existence which stands in opposition to contingent existence or even bare existence, van Inwagen then demonstrates that one problem with Kant's rejoinder to the ontological argument is that it can be shown that necessary existence is a property and it's possible to construct an argument that resembles the Cartesian argument, but yet does not treat "existence" as a real property. Nevertheless, it is important to make a distinction between existence and necessary existence.

Van Inwagen gives some examples of things that do not have necessary existence (they are not necessary beings) such as all human beings, the Taj Mahal, Mount Everest, the sun, and "for all we know," this universe is contingent (not necessary) because it's possible that although it exist, if the initial conditions were different, then this universe would likely not have existed. The point of these examples is that necessary existence is a property whereas mere existence is not: an object can exist without being a necessary object (p. 132-133).

While it's possible for someone to doubt that necessary existence could be an actual property of an object or thing, the point is that necessary existence is a possible property and it's a property (i.e., predicate) in the way that existence apparently is not. More importantly, necessary existence is not susceptible to the Kantian rejoinder since necessary existence, if it is a real property, could be added to a subject in a subject-predicate construction. So when van Inwagen establishes that necessary existence is a potential property, he then sallies forth this argument:

• A perfect being has all perfections.
• Necessary existence is a perfection.
Hence, A perfect being has necessary existence.
• Whatever has necessary existence exists.
Hence, A perfect being exists.

How should we evaluate the foregoing argument? To be sure, it's an improvement upon the Anselmian and Cartesian ontological arguments, but does this argument have its own flaws? While it is certainly better to posit necessary existence as a perfection instead of mere existence, van Inwagen points out why this version of the ontological argument is flawed. 

One problem is that the argument is invalid for the same reason the Cartesian version misses the mark: the premises of the retooled argument do not strictly entail its conclusion. To illustrate what's wrong with the "improved" version of Descartes' argument for the existence of God, van Inwagen introduces the notion of a negmount, which is a necessarily existent golden mountain. This object has three all negmontanic properties (i.e., necessary existence, being made of gold, and being a mountain). With this apparatus at hand, van Inwagen produces a counterexample to the improved Cartesian argument in order to test its validity. The argument goes this way (p. 134):

• A negmount has all negmontanic properties.
• Necessary existence is a negmontanic property.
Hence, A negmount has necessary existence.
• Whatever has necessary existence exists.
Hence, A negmount exists.

How does this argument fare. The answer to this question is fairly easy since negmounts do not exist; that tells us the conclusion is false and it's possible that the argument could never be true. A similar argument could be produced to show that round squares necessarily exist, but we've already established that such a conclusion would be false. But where does the argument for a necessarily existence negmount go wrong? Why is the conclusion not necessarily entailed by the premises?

18 comments:

Roman said...

Given modal reasoning (possible worlds), wouldn't one just need to posit the existence of a possible world in which God does not exist (i.e. a world in which nothing exists), to demonstrate that the argument is false? Since it would imply that both that God necessarily exists and necessarily does not exist?

Edgar Foster said...

I think van Inwagen addresses this point in the chapter but in the world of modal logic, if a being is necessary, then the being exists in all possible worlds. There is no possible world in which a necessary being does not exist because that's part of what it means to be a necessary being. It's like saying there is a possible world in which triangles are not three-sided. Someone could make the claim but they would be uttering a contradiction.

Another line of reasoning employed is that if God is possible, then God is actual. From that initial premise, then assert that God is possible, therefore, God is actual, with "God" being defined as a necessary being.

See https://www.oxfordbibliographies.com/view/document/obo-9780195396577/obo-9780195396577-0249.xml

Edgar Foster said...

I always liked Paul Davies take on atheistic statements in his book, The Mind of God. Davies wrote that "There is no God" might not be a formal contradiction but it could be false in every possible world like the statement, "Nothing is red and green all over."

Roman said...

Triangles have three sides is an analytic statement, God exists is a synthetic, So if you just say God exists because he's necessary by definition, one could simply argue that such a being is logically impossible because there is a possible world in which God does not exist, it's not a contradiction because "God exists" is not an analytic apriori statement.

So I guess if you start from the question of God's existence it can work.

1. If God exists, God is necessary (God exists in all possible worlds)
2. God is possible (God exists in one possible world).
3. Therefore, God exists in all possible worlds.

But let's say you go the other way:

1. If God exists God is necessary (God exists in all possible worlds).
2. If one possible world exists in which God does not exist, then God exists in no possible worlds.
3. There is a possible world in which God does not exist: One in which absolutely nothing exists.
4. God is impossible (God exists in no possible world).

I don't see how the former is valid but the latter is not.

Edgar Foster said...

I have posted about this before, but the ontological argument for God's existence does treat the statement, God exists, as analytic a priori. It defines God as a necessary being or as that than which a greater cannot be conceived. It treats "God exists" like "triangles are three-sided."

Now I agree that one could treat the statement as synthetic like cosmological arguments do, and start the argument with conditional statements, then avoid a contradiction. But for Anselm, the argument seems to be a priori and it does not start with a conditional statement.

Note how Anaheim makes use of the reductio ad absurdum inference after making the assumption that God is a necessary being. Descartes likewise treats God as a perfect being from the outset, a priori.

Edgar Foster said...

Also see http://edwardfeser.blogspot.com/2010/12/plantingas-ontological-argument.html?m=1

Edgar Foster said...

Anaheim should be Anselm. Another autocorrect.

Roman said...

I don't know of X exists could be an apriori statemnet, not since Kant's objection that existence is not a real predicate. i.e. X has three sides tells you something about X, X exists tells you nothing about X other than whatever it is, it exists, so a conception of a triangle that exists external to my conception doesn't differ from one that does not in conceptual content (Jean-Luc Marion, however, presented an argument once that existence is a real predicate, and he gave the example of money and time, I'll post if I remember where I found it).

Thanks for the Blog post by Feser, I suppose Plantinga accepts that the ontological argument doesn't demonstrate God, but only that if God does exists possibly he exists in all possible worlds, and if state of affairs exist in which God does not exist he exists in no possible worlds.

The problem is one would have to demonstrate that it is impossible that not anything exist ... I don't see why this is the case, Feser goes with Evil as a privation ... perhaps.

My hunch here is that applying modal logic to a being which is said to be necessary is gonna lead to problems (what seems to me to be a straight up contradiction, God is both necessary and impossible).

Edgar Foster said...

Thanks for the point from Jean-Luc Marion: I want to make a brief comment on that point along the way.

Peter van Inwagen basically agrees that mere existence might not be a real predicate, so he uses "necessary existence" instead which he thinks is not defeated by the Kantian objection and is a real predicate. Besides, van Inwagen submits that the existence objection deals with the periphery of the ontological argument instead of its center. He finds other problems in the Anselmian and Cartesian models, and the example you give about the triangle is similar to what Kant says about real thalers (currency) and conceptual thalers; Descartes employs triangles and mountains in his ontological argument. If memory serves me, Anthony Kenny presented an interesting argument for existence possibly being a real predicate: some have also treated it as a second-order predicate instead of a first-order property.

From what I remember about Plantinga, he was also trying to show that one could construct a version of the ontological argument that would not be invalid or subject to criticisms like the Anselmian version: two other interesting types of ontological arguments are Kurt Godel's and Robert Maydole. If you read all of van Inwagen's argument in Metaphysics, you will see that he winds up deciding the ontological argument shows that God's existence is possible but it does not close the case on the matter.

I think the last problem you mention can be avoided, if one starts with the assumption that God exists in all possible worlds (he is a necessary being). If the argument is set up with conditional statements, then someone could run an argument both ways, for theism and atheism. IMO, Anselm's ontological argument blocks that path.

Here is the short version of Anselm's argument:

1) God is that than which a greater cannot be conceived.

(2) Now that which exists in the understanding (in intellectu) and in reality (in re) is greater than that which exists in the understanding alone (in solo intellectu).

(3) If that than which a greater cannot be conceived exists in the understanding (in intellectu) and not in reality (in re), then that than which a greater cannot be conceived is one than which a greater can be conceived (reductio ad absurdum). But surely that cannot be.

(4) Therefore, that than which a greater cannot be conceived without a doubt exists both in the understanding (in intellectu) and in reality (in re).

Here is also Maydole's version: https://appearedtoblogly.files.wordpress.com/2011/05/maydole-robert-22the-ontological-argument22.pdf

Here's another argument for God's existence inspired by Scotus:

1) The existence of God is either necessary or logically impossible.

2) God's existence is not logically impossible.

3) Therefore, God's existence is necessary.

Hence, God exists in all possible worlds. The argument is valid and the premises are true, so I wonder how it would be susceptible to atheist rejoinders.

Roman said...

What about this reverse argument?

1) A state of affairs without God is either necessary or logically impossible.

1a) If God is a necessary being and exists there exists no possible world in which he does not exist.
1b) if a possible world exists in which God does not exist, either God is not a necessary being or he is impossible.

2) A existence of a state of affairs without God is not logically impossible.

2a) For example: a state of affairs in which nothing exists.

3) Therefore, A state of affairs without God is necessary: There is no God (conceived of as a necessary being).

I can't see why the Scotus inspired argument is sound but this atheist version is not?

I suppose one would have to deny (2), but I can't see why the existence of nothing what so ever is logically impossible.

I'm not nearly as learned as you are in logical issues, so perhaps I'm missing the boat. But I wonder necessary existence AS a logical necessity is not a contradictory notion, and thus cannot work within modal logical arguments, given the fact that both the modal ontological argument, and the atheist ontological argument seem to me to be equally sound.

Edgar Foster said...

Roman, there is a difference between soundness and validity. The common definition for validity in formal logic is "if the premises are true, then the conclusion necessarily follows from the premises" or "the premises necessarily entail the conclusion." On the other hand, soundness means that the argument is formally valid and the premises and conclusion are both true. Validity is easier to establish than soundness is: so I can tell you why the Scotus inspired argument is valid and why it's sound.

The argument is valid because the conclusion is necessarily entailed by the premises: it's simply a disjunctive syllogism. I say the premises are true because given the definition for God premise 1) must be true: it's pretty much saying that God either exists or God's existence is logically contradictory; hence, God does not exist. Those alternatives seem to be viable and true to reality as we know it. Additionally, it seems true that God's existence is not logically impossible since his existence does not involve a logical contradiction. Therefore, the other disjunct is affirmed in the disjunctive syllogism. Again, the argument is valid but whether it's sound is another matter.

Regarding the atheist argument: premise 1) has one disjunct being that a state of affairs without God is necessary. What does that mean? That it's possible for a state of affairs to be such that God cannot not exist? Why should we believe that premise?

I would not deny 2) because I don't think a state of affairs in which nothing exists is contradictory (logically impossible) although William Vallicella argues that something must exist (something exists necessarily). His argument may be valid but I'm not sure how sound or compelling it is.

I don't think logical necessity is a contradictory notion: these things are normally easy to demonstrate with truth tables and diagrams of arguments. But Inwagen points out that modal arguments for God's existence have limited value. The argument is not going to get us all the way there, contra what Anselm or Descartes thought. There will always be room for disputation with modal ontological arguments no matter how well they're constructed but the same could be said for cosmological arguments.

Just remember that soundness would mean the premises and conclusion are true and the argument is valid. Even if the atheist argument is formally valid, I would not say it's necessarily sound. To posit a state of affairs that is necessary is also not the same as positing a being like God who analytically is either necessary or maximally great.

Also see https://maverickphilosopher.typepad.com/maverick_philosopher/2016/12/is-the-modal-ontological-argument-compelling.html

Edgar Foster said...

To word matters another way, I think the ontological argument (formulated correctly) demonstrates that God's existence is logically possible, but the atheist rejoinder does not demonstrate that God's non-existence is either necessary or logically impossible since it doesn't show that God cannot not exist or that necessary non-existence for God is even possible. Secondly, the atheist argument does not demonstrate that the existence of God is self-contradictory.

Roman said...

Thanks for your patience, I may have been mixing up my terminology.

Perhaps soundness isn't the right term.

I think my issue is the statement "The existence of God is possible" when the object is a logically necessary being, because I don't know how necessity can be talked about as being possible or not meaningfully; is it possible that a triangle have three sides? I suppose so, but using the phrase possible implies that the contrary is also possible. So perhaps I would deny the second premise of the Scotus inspired argument, God's existence (in the sense of a logically necessary existent being) is impossible because a world in which nothing exists is possible.

I'm not saying I believe that (I believe in God) but I just don't think it makes sense to speak of his existence in terms of modal logical necessity.

So perhaps my atheist formulation was unsound because of the first premise. But what I meant by that is that if a state of affairs exists in which God does not exist (in terms if a logically necessary being) then that logically necessary being does not exist in any possible worlds since if he exists in one he would have to exist in them all, so one only has to posit one possible world without God to throw the whole thing off.

Now it might be the case that there is no possible world without God.

I agree that logical necessity is not contradictory, but I think logical necessary existence might be; since that would entail that the existence of nothing at all is logically impossible.

Anyway, I'm sorry if I'm just being dense, but I appreciate your patience. And I think I may have been using the term "sound" in the correct way, perhaps I meant convincing.

Roman said...

BTW I have not yet read the two last links you posted, perhaps they'll turn on some light bulbs.

Edgar Foster said...

This book might be helpful: https://oxford.universitypressscholarship.com/view/10.1093/oso/9780198746898.001.0001/oso-9780198746898https://oxford.universitypressscholarship.com/view/10.1093/oso/9780198746898.001.0001/oso-9780198746898

It includes a defense of S5 logic.

Edgar Foster said...

I don't think you're being dense but one problem is how different sources use terms or define them.

One issue is what we mean by "possible" or possibility. Some types of possibility include epistemic possibility, modal possibility, sunjunctive possibility, but in this discussion, I am referring to logical possibility which some books define as a statement/concept that involves no contradiction or self-contradiction. In that sense, it seems that one can talk about whether a necessary being (the thing or concept) is possible because we're just asking whether the being is a coherent notion or not. Does the concept entail a contradiction? While someone might not question the possibility of triangles not having three sides, other things about triangles could be questioned, like whether it's possible for a triangle to exist outside the human mind. That would involve modal possibility. But in the case of God, we're talking about logical rather than modal possibility, then I don't think the contrary would necessarily be entailed. The logical possibility of 2 having a square root does not entail "2 does not have a square root." One statement does not entail a contradiction whereas the other one does; one statement is logically possible but the other is not.

I've also seen philosophers reason that if God is possible, then God is actual but we don't normally reason, if God is necessary, then God is modally possible. At least, that's not what I think Anselm or Descartes are doing. However, I emphasize that throughout this discussion, I've been using "possible" in the sense of logical possibility and it seems that not all things are logically possible.

Personally, I don't think the existence of nothing at all is logically impossible (formally contradictory), but it's questionable at least whether total nothingness is modally possible. Moreover, why should we believe that there is a possible world in which nothing whatsoever exist? Okay, the idea is not formally contradictory, but to argue that there is a possible world in which of necessity, there is nothing seems like an extremely strong claim to me. I'm not trying to be biased, but to say "God" is necessary makes more sense because the property is built into the concept like three sides of a triangle. When theistic philosophers say, "It's possible that there is a necessary being," I just think it's a way of articulating logical possibility, and this kind of possibility does not necessarily entail the truth of its contrary.

Edgar Foster said...

This conversation:

Plato: "It is possible that there are Martians"
Socrates: "It is possible that there are not Martians"

is different from:

Plato: "It is possible that p and not-p is true"
Aristotle: "It is possible that p and not-p is false"

Aristotle would definitely have the upper hand against Plato.

Edgar Foster said...

The IEP contains this formulation of Anselm's argument:

"God is, as a conceptual matter (that is, as a matter of definition) an unlimited being. The existence of an unlimited being is either logically necessary or logically impossible. The existence of an unlimited being is not logically impossible. Therefore, the existence of God is logically necessary."

Could we make a similar argumenr for a necessary world or universe? If so, that would mean a non-contingent universe (world) is logically possible. But all that we know about the world tells us the world is contingent, not necessary, and maybe that's the way things have to be.