Barth on Intelligent Design
... familiar with the groaning of all creation, we lend our support to all honest, secular, scientific and historical research; but we dissociate ourselves from every semi-theological interpretation of Nature and of History.—Karl Barth, The Epistle to the Romans, trans. Edwyn C. Hoskyns (London: Oxford UP, 1933), 318
Comments
Suppose, for instance, the American Academy of Science issues a statement that "All life on earth is a product of blind evolution, i.e. by chance rather than divine intervention." I cannot imagine that Barth would applaud such a statement, rather, I think he would be happy with someone like Plantinga who pointed out to the AAS that this was really a politicized religious claim rather than an empirical, scientific one.
But, of course, perhaps this is what Barth is pointing to by endorsing "honest, secular" research. Of course, such notions are problematic, because of the way descriptive and normative statements are entangled, etc. etc. But let's grant Barth that there are things that are much closer to being "honest, secular" scientific claims (mathematics, chemistry) and others that are much more like dishonest, covert religious claims in scientific claims' clothing (sociology, history).
But if we think it's good that there are Christian philosophers and scientists who work quite diligently to expose the difference between the two kinds, then we should ask what kind of inquiry are they involved in? In order for a Christian philosopher to make a persuasive argument to the AAS, he has to make a "secular" argument, i.e. one which you don't have to be a Christian to believe.
"So far so good," I think Barth would say. But here's the problem: If Plantinga's job is to make secular or public arguments, why should Plantinga not also try to produce secular arguments for the existence of God? Barth would presumably be happy with the former (more negative) activity, but deeply unhappy with the latter (more positive) one.
But what is really the difference between the two. Let's say that Plantinga is quite aware of the difference between proving that there exists an infinite, necessary being and proving that God was incarnate in Christ, so it isn't that Plantinga would be trying to prove Christianity true--more it would be trying to advance secular arguments that would prove certain propositions which are necessary, but not sufficient for Christian belief. (The tradition calls them the "preambles" of faith.)
Barth could say that natural theology is impossible, but if he would say so he'd be making an empirical, not a theological claim. Because if Plantinga comes up with one successful proof for the existence of an infinite, perfect being, then bam! natural theology works. To claim that natural theology is impossible is to claim that there are no propositions about God which can be proven in a secular, publicly accessible way. But this is an extremely bold claim, which to my knowledge, has no adequate support.
Shane,
I'm curious whether God's existence is necessary for Christian "belief" as you put it, or for Christian truth. By belief do you mean human ascent or the idea itself? I assume you mean the truth itself.
As for your view of Barth, it seems to be a straw man argument (although perhaps there's deeper history with Barth that's not showing up here). The "Barth that could ____" is far from the Barth that did _____ in this case. What did he do? As far as I can tell, Barth did not claim that natural theology is impossible. He claimed that it's irrelevant for the job of the theologian. A case and point of natural theology is when a theologian tries to prove the existence of God.
Plantinga may have an argument for the existence of God, but the only reason we might say "it works" is because it happens to convince people that it's true. That is the world of honest, secular, scientific and historical research as I understand it: it completely works off of pragmatic assumptions. If God's existence is somehow pertinent to public secular society, then they'll find ways of making it work I'm sure. My hope is that they do, if only so that Plantinga can stay employed.
Of course, the Christian looks back and sees (as Ben has pointed out) the utter contingency of creation upon God. Hence, we should not be surprised that proofs for the existence of God show up in philosophy, that evidence for the existence of God shows up in science, etc. - all as "groaning of creation," a reflection of God. Our own attempts to get at that which transcends us also reflects this.
Theology and science have different pragmatic tasks. Arguments for the existence of God aren't necessary. This is different from saying that God's existence is necessary. Theology already assumes God exists (as you put it, it is necessary but not sufficient for theology). This is just axiomatic. Now suppose a scientist decides he wants to be a theologian because he comes across a robust argument by Plantinga. There's a paradigm shift inherent in that switch in terms of "what works." The scientist belongs now in the community of theologians. The relevant question becomes "Who is this God and how does it exist in relation to us?"
Christian philosophers work ultimately work for secular society, not for theology. They made add numbers of converts to the church based on their arguments. They may provide science with a critical realism that opens itself the wonder and mystery of creation, creating new methods of study that get us more knowledge about the world (that's their job after all).
But when the agenda of secular society begins to creep into theology, that's when Barth declares "Nein."
I think I can formulate a better response to the argument you regularly give in favor of natural theology — viz., that if a person gives a rationally compelling proof for the existence of God, natural theology is a demonstrable fact. Along with that, you say such proofs are a necessary though not sufficient condition for theology. I would like to give a much stronger response than Chris gave, though I stand behind what Chris wrote.
My response: Philosophers can give all the proofs for "God" that they can think of, and I'll go ahead and grant that all of them are rationally persuasive, but that isn't natural theology because no such proof will actually be talking about God, despite the use of the same word. No proof can possibly speak of the God of Jesus Christ. No proof can make the gospel rationally persuasive. That is why we must and do distinguish between a theist and a Christian. But unlike most Christians, I do not see theism as a building block toward the Christian faith. Theism has no material relation to Christian belief, since there is no indication -- I would even say, no possibility -- that the theist is talking about the same God to which Christians refer. Theism and atheism are just two sides of the same secular coin.
Now: you may wish to assert that rational proofs for the existence of God is in fact natural theology, and I would grant this as long as we sever any relation between natural theology and Christian theology. Here I would prefer the simpler distinction between philosophy and theology.
So, to get back to your comment, in my opinion, a Christian philosopher is like a Christian scientist: both work in an environment of "honest, secular" research. Neither should claim to be talking about God; they have their own specific fields of interest, but that interest is not God, at least not the Christian God. The Christian theology is on a whole different level, because she is not engaged in "honest, secular" research; she is engaged in the task of talking about God, the task of proclaiming and explicating the gospel of Jesus Christ. She does not work as part of the public arena; she works primarily as a member in the body of Christ. She does not make scientific or religious claims; she explicates the claim that God has upon us.
We need to distinguish between God's existence, which I accept as necessary but not sufficient, and the proofs for that existence (which I don't believe are necessary). I read Shane as saying the former, not the latter.
In my more modest response, I keep away from saying that there is no possibility that theism and Christianity are talking about the same God is simply because there can be no argument to prove that.
Furthermore, I'm not willing to throw out God's revelatory activity (however much Jesus Christ might be veiled and unrecognizable in it) within the world. Thus, if I allow creation's rational contingency on God's rationality, then I must allow that a scientist must see God's reflection (though not perceiving). If I do this for science, there's no reason why I shouldn't allow philosophers who posit God's existence to see God's reflection (though not perceiving). There's an infinite qualitative difference in knowledge, but the same God works in both.
God cannot be used in scientific accounts of the universe, because that would be to reduce the Creator to the status of a creature, the Maker of heaven and earth to a member of heaven and earth. Such a move lies behind the "God of the gaps" fiasco.
What would Aquinas say? Shane may correct me, but I think he'd agree. I think that while it's a no-brainer that the Angelic Doctor would affirm that there is an Intelligent Designer, he would be as scornful of the arguments for Intelligent Design as he would be of Paley's original (a "silly" argument, says the Dominican Herbert McCabe).
And Fergus Kerr has some interesting things to say to the point in After Aquinas: Versions of Thomism (2002). Citing Victor Preller, Kerr agrees "that Thomas clearly thinks that the proposition 'God exists', held as true by a non-Christian, on the basis of theistic proofs, does not mean the same as the proposition 'God exists' held by a believer. Pagans ... may believe on rational grounds that 'God exists'; but this would not be believing truly that 'God exists', since they do not hold this belief sub his conditionibus quae fides determinat." Fast-forward to Pascal - and Barth!
And speaking of Barth, Kerr also refers to the "intriguing argument" of Eugene Rogers that "Thomas and Barth end up maintaining essentially the same position about the possibility of natural knowledge of God... Natural knowledge of God's existence independently of the life of grace, Rogers insists, is not something that Thomas ever imagined. The functon of the cosmological arguments in Summa Theologiae, he concludes, is to 'fulfil the charge of sacred doctrine to leave no part of the world God-forsaken'."
And Ben's comment - it brings togethert Barth and de Lubac, in his massively influential re-interpretation of Thomas, does he not? (Cue a look at Barth's later "theology of lights".)
All this is part of what you might call the "new look" on Thomas' Five Ways.
Finally, slightly off-topic, I love the letter Barth wrote to his grandniece, who had apparently been wrong-footed by the seeming contradiction of Genesis and Darwin. Barth writes:
"Has no one explained to you in your seminar that one can as little compare the biblical creation story and a scientific theory like that of evolution as one can compare, shall we say, an organ and a vacuum-cleaner - that there can be as little question of harmony between them as of contradiction?"
The first thing I want to point out is the difference between a proposition "p" and the proposition "p is provable".
There are four possible relations between "provable" and "p":
1. "p" is true and provably true.
2. "p" is true but not-provably true.
3. "p" is false and provably false.
4. "p" is false but no-provably false.
(establishing 2 and 4 in the logical language of arithmetic is the goal of Gödel's Second Incompleteness theorem. NB: if p is provable, then it is true and if p is disprovable then it is false.)
Now, let's take the proposition "God exists". It is necessary in order for a person to be a Christian that believe this proposition is true. But note that I am not saying that one must believe that this proposition is provable to be true to be a Christian. So you can affirm "God exists" according to either (1) or (2) above.
But is it provable or disprovable that God exists? (Pace Chris we aren't talking about pragmatics here, because we are just assuming that if there is a true argument demonstrating the existence of God, then it will be successful in the pragmatic sense, but its truth doesn't come from the fact that it is persuasive to people, rather the other way around.) All I can say is that it is clear that nobody has put forward a completely successful proof or disproof of God's existences in the 2500 odd years of philosophical reflection, although there are certainly some very suggestive results in both directions. A pessimist might take this problem as insoluble just because of its longevity, but that's just the coward's way out. "Everything fine is difficult" as the Greeks say and certainly the history of mathematics tells us of
"http://mathworld.wolfram.com/GeometricProblemsofAntiquity.html">seemingly insoluble problems which are somehow resolved centuries after they are proposed.
Of course, as David rightly points out, this all depends on what we mean by "God" (and this also bears on the meaning of the term 'natural theology'). Now I take 'natural theology' to mean that subsection of metaphysics which investigates God rationally. It is this mode of investigation which distinguishes natural theology from revealed theology where God is investigated on the basis of supernatural revelation. David says that whatever a natural theologian might prove about God can have no purchase on the God of Jesus Christ. This response attempts to draw a divide between philosophy and theology, leaving the secular pursuit of philosophy intact, but denying its significance for (revealed) theology.
My disagreement comes back to the definition of "God" in the proposition "God exists". I take "God" to point to an infinite, perfect, necessarily existent being who is simple, good, omnipotent, omniscient, transcendent, benevolent, impassible, etc.
Now suppose (just for the sake of argument) that I create an argument that proves such a being to exist. From this I can prove that there is exactly one such being.
(A perfect being must possess all attributes that would make it good and must possess no attributes that would make it bad. It is impossible to suppose that two such beings exist because there could be no attribute which they would not share. If perfect-being-1 possessed A and A is a perfection that perfect-being-2 lacks, then perfect-being-2 is not perfect, contrary to our assumption. Therefore, by the identity of indiscernables there is at most one perfect being. This argument is blatantly stolen from Thomas.)
If I have proven logically that there exists at most one perfect being and that such a being actually does exist, then I am talking about the only God who exists whom I also believe the basis of revelation to be incarnate in Christ. It is the same God who is spoken of in both my logical argument and the creeds of the church.
What value does natural theology have for revealed theology? Well the proof of the pudding is in the eating. To really answer this question, you'd have to spend a lot of time looking at dogmatic theologians who were also natural theologians and trying to sift out where the ideas came from and how they are interrelated in his work. My suspicion is that you aren't going to find anybody on this side of the enlightenment who has engaged in this kind of enterprise, so it may be that we need to make a retrieval of some parts of the pre-critical Christian heritage to find out how to do this well. So I think we in the 21st century still have a lot of work to do before we can really try to answer this question well.
Now, to respond to Kim, I don't think we ought to postulate a God of the gaps, but the problem with the "god of the gaps" idea is that it presupposes that science is limitless, boundless, will eventually explain everything that is in need of explanation, etc. The danger of the god of the gaps strategy is that your gaps threaten to shrink. But, I am convinced that there are significant "gaps" which empirical science can never penetrate. "Why is there something rather than nothing?" If a guy in a labcoat tells you he has a solution to that question, slap him and tell him to get back to his test-tubes. God is a good solution to that problem and we don't need to worry about science somehow providing a superior explanation in the future.
Now, with regard to Thomas. I simply cannot see what Rogers can mean. Thomas believes that the existence of God (with a big G) can be proven a posteriori through creatures (ST 1a, q. 2, a. 1). I find it hard to believe that Thomas would say that only a believer could know that God exists because each of his "five ways" are taken from a passage in Aristotle. (Argument from motion in Physics VIII, also look at the Metaphysics XII). I just don't see any harmony between Thomas and Barth on this point.
Now it is true that Thomas thinks that all knowledge we have comes by grace to some extent, but this is also clearly different from what Barth would say. Perhaps Rogers means that nobody could learn God's existence for Thomas apart from natural grace, but I'm not sure what the point of saying such a thing would be. And it seems clear to me that Barth would be tremendously unhappy with people learning things about God from creatures on the basis of natural grace.
The distinction which you point out between God's existence and proofs for God's existence is an important one, but Shane's argument (I believe) rests on the assumption that proofs of God's existence are actually talking about the existence of God -- and that is not something I am willing to grant. As Gordon Graham has made clear in my classes with him, the best that all the classical proofs can reach is the notion of a Supreme Ground of Being (not unlike Tillich's Ground of Being). But to go any further is impossible. And from my point of view, unless you begin with the God who raised Jesus from the dead, you may as well give up talking about "God."
Kim,
Great comments! I was especially intrigued by Kerr's statements.
Shane,
I haven't read your comment yet, but I will now.
Very well stated and argued -- but I just can't shake the conclusion that we are talking about two very different things. You wrote:
My disagreement comes back to the definition of "God" in the proposition "God exists". I take "God" to point to an infinite, perfect, necessarily existent being who is simple, good, omnipotent, omniscient, transcendent, benevolent, impassible, etc.
The question that any modern theologian would ask you is: How in the world can you know that this is what defines God? How are you not simply engaging in pure speculation? How are you not, finally, simply engaging in philosophy and not theology?
The problem with all metaphysical theologians is that they come to God with a presupposed understanding of divinity (and humanity). Metaphysics talks about God by first talking about something else, and you have made it quite evident here in your comment. Even if you could rationally prove that your "God" exists -- and I fundamentally deny that there is such a proof -- on the basis of God's self-revelation, I would have to assert that your logic has simply proven a figment of your imagination, that your logic is "bouncing off the clouds" (so to speak) and remains trapped in your own finite reality. I would assert that despite the beauty and even persuasiveness of your argumentation (which is itself purely speculative, since no such argument can possibly exist), you are in fact talking about a no-God and not the living God, Creator of heaven and earth.
The closest I could come to your four relations between "p" and "provable" is #2. But even here I would deny that God is an object among other objects which our logic can order and define in such a schematic way. God must give Godself to be known, and that's where we must begin.
David, I don't see what you are trying to accomplish with this objection. I "define" God to be that being who is infinite, perfect, necessarily existent, etc. Now there is a long way to go from making a definition of a thing to proving that that thing actually exists, but that is of course, precisely what those proofs of God's existence are trying to do, to make the leap from the theoretical to the actual.
Now as to the charge that this is abstract speculation. Suppose I define a "prime number" to be a number which is evenly divisible only by any integer except itself and one. Now what I would need to do is to prove that this property is actually instantiated; for example, that the number 11 is a prime cannot be evenly divided by any integer except itself and 1. (I have no idea how to do this, by the way.)
The definition of a prime number itself does not prove that any such things as prime numbers actually exist, true enough. But if someone were to object that my definition of prime numbers was just idle speculation it would seem to me that he had missed the point because I have to make the definition of a prime before I go about trying to prove that there are primes.
I can only understand your objection as coming from some sort of kantian starting point where the only possible objects of knowledge are phenomenal object and not the things in themselves. But of course, I find Kant extremely problematic on this issue (more on this when I finally get around to finishing a piece I'm doing for Travis on Barth on Kant). At any rate there ought to be some sort of argument produced to show why Kant is right about knowledge of things in themselves. (Kant himself never provides any real argument that the old metaphysics is wrong, incidentally, he just asks us to pretend 'as if' it were the case that all we know are the phenomena).
What I found most interesting about your response was the claim that you know on the basis of revelation that there are no possible proofs of God's existence. I don't accept a hierarchy of sciences where the conclusions of theology must be presumed by the philosophers because they are putatively based on the revelation of pure true in Scripture, but even if I did, I would find this claim of yours quite strange, because that theological tradition has affirmed that "It is provable that God exists" is a revealed truth on the basis of Romans 1. I'm open to the suggestion that the tradition might be wrong about this, but it certainly doesn't seem as clear cut a matter as your response would seem to indicate.
sw
the definition of a prime number is a number which is not evenly divisible by any integer except itself and one.
Logical arguments should begin from the weakest assumptions possible. So perhaps I should being with a much weaker definition of God and then proceed to try to prove those other attributes, omnipotence, omniscience, etc. in their own subarguments rather than just bringing them all in with the initial definition.
(Pace Chris we aren't talking about pragmatics here, because we are just assuming that if there is a true argument demonstrating the existence of God, then it will be successful in the pragmatic sense, but its truth doesn't come from the fact that it is persuasive to people, rather the other way around.)
Thanks for clarifying this. I agree with you, but I don't think it's necessary (nor is it the case) that secular science would agree you in order to continue research.
But is it provable or disprovable that God exists?
What are the criteria for a proof? Are these criteria not simply our own devices? It seems to me that we cannot get away from ourselves (and thus pragmatics) when we prove God's existence - the only thing we can do is deny the skeptics to give ourselves some comfort. If we take sin seriously, then we will have no choice but to let the possible proof remain possible only within the realm of our own existence.
God's existence is never separated from the rest of God's being. Thus, while it is logically necessary to say that God exists, the existence is predicated on "who God is" to the extent that if one cannot prove God is loving, one cannot prove God exists. Since sin clearly blinds us from seeing God as a loving God, we cannot see God as existing either.
The idea that revelation is purely a supernatural event is of course taken the human perspective. However, if we look at this revelation a posteriori, and this revelation (Jesus) tells us that he is the exegesis of the Father, then it is God's nature to be the revealing God.
As I understand revelation from Barth's view, the idea of a natural grace as something given to humanity's constitution is denied. But following Torrance, this is not to deny God's revelatory work in the world in spite of our total depravity.
1. God is gracious, merciful, and patient with creation (different from natural grace).
2. The created rational human mind's comprehension of transcendence necessarily reflects the Creator's constant sustaining of creation, even as it is insufficient for salvation.
3. Such comprehension does not deny the reality of total depravity. Total depravity says that humanity in sin is insufficient for God. This does not deny natural knowledge, but completely relativizes it from salvation.
4. The God of "the proof that God exists" is not identical to the God of Christianity. The God of the proof can never get beyond the infinite qualitative difference. It remains in the human realm, the human mind. There is no point of contact ontologically between them.
5. But we do not have to deny a logical direction from the Christian God to the God of the proof, given what I've said earlier on God's presence with creation, which cannot be denied. It seems that we must allow God room to work through the proof if He so chooses.
I apologize for working this through in such long form. Thanks to everyone for their stimulating remarks.
I also think your opinion of secular scientists as moneygrubbing pragmatist sinners scampering for grant money is unrealistic. I don't think anybody goes into science for the money.
Again (following Eric Mascall): for Thomas, "God has proclaimed his own existence [in Exodus 3:14]. The truth of the proposition 'God exists' has been divinely revealed - and now we may look for ways to demonstrate or manifest it, ways in which to probe or test it."
Again, Barth's later "theology of lights" comes to mind, the notion that the heavens do indeed declare the glory of God - but like a "cat's eyes", shining only as they are lit by the John 1's light shining in the darkness.
I am not saying that there is an exact fit between Aquinas and Barth on the relation of natural and revealed theology - I think that Rogers is over-the-top, that he underestimates Barth's radical inversion of the two. But the idea of natural theology as a corollary of revealed theology, it seems to me, is worth exploring (though better refer to a "theology of nature" rather than to "natural theology"). And not least because - an important historical note - the early Barth's unconditional hostility to natural theology - including his nasty Nein! to Emil Brunner - must be seen in the context of Third Reich theology.
I like Kerr a lot, but I don't think Thomas believes that "it is a matter of faith that it is provable that God exists". He thinks it's a matter of fact that it is provable that God exists--precisely because Thomas believes that he has proven that God exists and his arguments for this don't presuppose any revealed truths, they are just good old fashioned Aristotle.
Now, Thomas also distinguishes two kinds of propositions about God:
(1) Those necessary for salvation and knowable by faith alone.
(2) Those which are knowable by either reason or faith.
Examples of (1): "God is three persons in one substance". For Thomas you aren't going to heaven if you don't believe in the trinity and there is no way to come to this doctrine apart from the revealed catholic faith. Period.
Example of (2): "God exists" or "God is one"
Now, Thomas says that revelation (and therefore sacred theology) was still necessary, even though there are some truths about God knowable naturally because (2.1) even if those truths were discovered rationally, it would only be by the best and the smartest whereas salvation should be universal. Moreover, (2.2) even the best and the brightest will be apt to err about such difficult subjects. So even though Aristotle can know something about God as it turns out he doesn't have it completely right because he still thinks that the world is eternal, etc. Of course Aristotle got some things right too (read Metaphysics XII). This doesn't mean Aristotle's is getting in to heaven, it just means that he was smart enough to figure a few things out which we now understand much better in the light of revelation.
Some of the propositions revealed in the Bible are type (2) propositions and God reveals them even though it isn't strictly speaking necessary because some people are stupid or illiterate and they don't have the ability to come to know these truths about God by reason.
Here is Thomas's text (ST 1a, q. 1, a. 1 response):
"It was necessary for man's salvation that there should be a knowledge revealed by God besides philosophical science built up by human reason. Firstly, indeed, because man is directed to God, as to an end that surpasses the grasp of his reason: "The eye hath not seen, O God, besides Thee, what things Thou hast prepared for them that wait for Thee" (Is. 66:4). But the end
must first be known by men who are to direct their thoughts and actions to the end. Hence it was necessary for the salvation of man that certain truths which exceed human reason should be made
known to him by divine revelation. Even as regards those truths about God which human reason could have discovered, it was necessary that man should be taught by a divine revelation; because the truth about God such as reason could discover, would only be known by a few, and that after a long time, and with the admixture of many errors. Whereas man's whole salvation, which is in God, depends upon the knowledge of this truth. Therefore, in order that the salvation of men might be brought about more fitly and more surely, it was necessary that they should be taught divine truths by divine revelation. It was therefore necessary that besides philosophical science built up by reason, there should be a sacred science learned through revelation."
"But sacred doctrine makes use even of human reason, not, indeed, to prove faith (for thereby the merit of faith would come to an end), but to make clear other things that are put forward in this doctrine. Since therefore grace does not destroy nature but perfects it, natural reason should minister to faith as the natural bent of the will ministers to charity. Hence the Apostle says: "Bringing into captivity every understanding unto the obedience of Christ" (2 Cor. 10:5). Hence sacred doctrine makes use also of the authority of philosophers in those questions in which they were able to know the truth by natural reason, as Paul quotes a saying of Aratus: "As some also of your own poets said: For we are also His offspring" (Acts 17:28). Nevertheless, sacred doctrine makes use of these authorities as extrinsic and probable arguments; but properly uses the authority of the canonical Scriptures as an incontrovertible proof, and the authority of the doctors of the Church as one that may properly be used, yet merely as probable. For our faith rests upon the revelation made to the apostles and prophets who wrote the canonical books, and not on the revelations (if any such there are) made to other doctors."
I used "pay-off" purely in a colloquial sense, and don't mean to suggest that scientists are money-grubbing (though they'll probably make more bucks than you and I ever will). I'm talking about pragmatics purely in a philosophical sense, where the threshold for truth has become reliant on the social community and its instrumental value. Now I don't do theology with this epistemic viewpoint (although there might be valuable things to learn from Peirce, James, Dewey, Rorty, Haack, etc.), but I think pragmatism is a valid description (and perhaps a self-fulfilling prophecy) of how scientific inquiry takes place, and how the notion of truth is socially constructed and operates within that society.
I don't think you'd find that 'social construction' has penetrated very far into the circle of the hard sciences. At any rate, I'm not impressed by the idea that truth is socially constructed, but for more see Keith DeRose's excellent article here. It's longish, but worth it in my opinion.
sw
Shane: How did you reach this definition of God? How did you come to agree that this definition is suitable for the name, "God"?
The deep problem with your analogy of the prime number is that either (1) you have been told by others how to define a prime number, or (2) you created the notion of a prime number off the top of your head. The problem is, neither of these methods will work for defining God. Just because a trusted expert in some field of study tells you that God is X, Y, and Z does not mean that God is actually X, Y, and Z. And surely we do not have the freedom to define God willy-nilly for ourselves.
It seems that the only way we can properly define God is a posteriori — viz., after we have encountered the living God. And we encounter God in Holy Scripture, which attests to God's self-revelation in Jesus Christ.
I think the classical tradition of Christian theology is really in tension with itself here. On one hand, the ancient theologians were committed to Scripture. I fully believe that Thomas is a biblical theologian, as were those who preceded and followed him. But throughout there is a tension within the tradition between adhering to Scripture and wanting to align Scripture with external a priori definitions of God, humanity, the world, etc. This tension is never resolved. Kant has enabled modern theologians to resolve it in one way. Hegel is another way. And I think Barth offers the best way, at least the best way that we have yet seen.
The point is, we have three basic options, as I see it: (1) allow God to define God through Holy Scripture, (2) allow things in this world to define God, or (3) try to make the two fit together as successfully as possible.
Well, for instance Thomas Aquinas would agree with the a posteriori part--Thomas's five way are a posteriori arguments from creatures that there must exist some first cause who is the highest being and the most perfect, etc. I'm not sure that a priori arguments are necessarily out of the running though. The ontological argument has received a bit of attention in the 20th century and has a couple of interesting defenders, including Kurt Gödel and Alvin Plantinga.
"The problem is, neither of these methods will work for defining God. Just because a trusted expert in some field of study tells you that God is X, Y, and Z does not mean that God is actually X, Y, and Z."
It's odd that you say this because all theological arguments are arguments from authority. But, patently, what I'm engaged in here is not revealed theology--it's metaphysics = first philosophy = natural theology, so by the nature of what I'm doing I will not accept arguments from authority (even the authority of Scripture).
Now as to where I get the definition from--well, it comes from the fact that I'm a Christian and I want to prove that God exists without invoking revelation. So, I think to myself on the basis of my faith What is God like? Well, he's the best thing, the most perfect, he knows everything, he's morally good, and so on. So, when I am trying to make my philosophical argument that God exists what I am trying to do is to give a secular account that what I initially believed on the basis of faith is true, and an argument can be given for its truth which does not depend on the authority of scripture, church councils, the pope, etc.
Now, I think part(s) of the problem that you are having with the idea of "definition" here comes from two misunderstandings.
1. You don't say this explicitly, but perhaps you are worried that if I am free to define 'God' one way, then somebody else is free to define him another way, which would imply that "God" is just a subterfuge word, an expression of a hidden will to power, which does not correspond to anything that really exists outside of my little logical game. Objection 1 is the relativism objection.
2. Objection 2 is the Barthian objection: only God gets to define God--if you define God then you have made an idol, not spoken truly of the living God incarnate in Christ, etc. etc. etc.
I'm going to ignore objection 2, even though I think it's wrong, because we've had this conversation before.
On the other hand, i think Objection 1 is relatively simple to clarify--the definition I postulate is a universal definition. When i define prime numbers, I'm doing something like 'discovering' primes, not 'inventing' them, because as it turned out prime numbers existed before anybody thought about them.
Now the thing about logic is that it comes in lots of flavors. Just like in the 20th century we have non-euclidean geometries (which come about by denying or omitting axioms of ordinary plane geometry), so too we have non-standard logics where certain axioms are omitted or altered. Alternative logics might prove "weaker" (able to prove less) than standard logic or they might be "stronger".
None of this should be taken to imply a 'relativism' in logic however, because logical arguments are always conditional: if the premises of this argument are all true, and its conclusion is validly derived from its premises, then the conclusion is true. Now, if you don't like the conclusion, then you have to identify the faulty step in the reasoning, or you have to deny one of the premises. What alternative logics are doing is denying the premises.
Now, suppose I make a nice looking proof of the existence of God--the thing that will make it a nice proof will be that it starts from premises that an atheist would not like to deny, for instance: "Every change is caused by something" or "An infinite regress of causes is impossible". If I manage to prove the conclusion "Therefore, God exists" on the basis of these two premises, then the atheist is in the difficult situation of either having to admit that God exists or having to deny that an infinite regress is impossible.
Contrariwise, the atheist can take my same definition of God and try to use it against me, as for instance J. L. Mackie's argument from moral evil. Mackie's argument goes basically like this, ok, let's say that God exists and is Good and all-powerful, like the christians and jews and muslims say. Now good people do all they can to eliminate evil in the world. Now the theist is in a bind because if God is all-powerful, then he has the ability to remove evil, but apparently not the desire to do so, which makes him evil rather than good. Likewise, if God is good, then the existence of evil must show that he is not in fact all-powerful. Therefore, it is impossible for there to be a good, all-powerful divine being.
Now, if Mackie's argument were correct, then we all ought to turn in our WWJD bracelets for black turtlenecks. If this argument were right it would prove christianity false. (Fortunately it isn't right--Plantinga has shown why to my satisfaction).
And this is how we go back and forth. I don't think it's an unfruitful undertaking though the conversation is longstanding, because everything fine is difficult and the task requires a lot of insight and logical subtlety. And there are new things said from time to time. (Check out Gödel's version of the ontological argument linked above. It floored me when I first read it a couple years ago.)
Sorry to drag this out to such a length, but i think it's an important point and worth spending some time elaborating.
sw