My objection is simple. Your premise 2 is fudged by you to suit your subsequent argument. Try it with the one that's sensible and your argument no longer holds. Nor does it if you use "knowledge" premises instead of logic ones.

I have a similar objection:

1. If there is no god, knowledge is not possible.
2. Knowledge is possible.
3. Therefore a god exists.

If ‘(P) The food is poisoned’ is in accord with reality, then P is true. So if to have knowledge is to know that P is in accord with reality, then knowledge is possible.

I am confused by your objection because nothing in my subsequent argumentation relies on claiming that (2) is false. In fact, for arguments sake I assume it's true. So where is the problem?

in the paragraph below, it looks as if you are claiming that #2 is unsupported. (especially the underlined which reads like "so how do they justify #2?", which you answer with 'because god said so' which would of course be quite contentious.)

cwoc was just trying to say that #2 is supposed to be presented in a form that is obviously true and acceptable to everyone. ie, I don't need to know anything about whether or not there is a god to accept that logical claims are true.

As you said later, #2 should never be a point of contention. I think the way you presented it is fine, but that your paragraph of text quoted here is somewhat misleading in that it seems to prompt an argument where none should be.

edit: Was that paragraph supposed to be talking about #1? Because it sounds like you are talking about 2, which is really unnecessary. 2 isn't supposed to include god at all, so maybe its just a misinterpretation because the language is similar.

Either Original Position was unclear in his writing or Cwocwoc misread his point

I cannot find any way to work out which is more likely.

1’. If there is no god, then it is not possible to know that ‘(P) The food is poisoned’ is in accord with reality.

P is certainly not true by definition; P is true iff it is in accord with reality. I guess I just don’t see the relevance of your counter, even if we accept that all logical truths are tautologies.

Thanks for the clarification. I kind of just threw up a huge wall of text, so it is not as clear as it might be.

Yeah, it is talking about (1). It is supposed to be an explanation for how the truth of logical claims are grounded if there is a Christian God.

This isn't helping me. I don't know what "counter" you're talking about and I don't know what you mean to be disagreeing with me about.

If it helps, a cleaner phrasing of (1) would be this:

1a) If the Christian God doesn't exist, then logical claims aren't true.

Incidentally, the reason I used the phrase "Logical claims are true" rather than talking about the existence of logical absolutes as some presuppositionalists do is because that might end up begging the question about the existence of abstract objects--which would mean that many would end up rejecting (2).

i.e. many more philosophers would (I think) agree with the claim that logical claims are true than that logical absolutes exist.

As far as TAG is concerned, can't you just substitute "Jewish" or "Flying Spaghetti Monster" for "Christian" and the argument would be identical? I thought it was more of a generic, existence of a god, as opposed to existence of my god but not your god. Where does christianity fit in, to the exclusion of any other?

I’m just trying to understand it and how you’re attacking it.

Is it fair to say that you’re not arguing against the assertion that the Christian God may serve as ‘a’ necessary condition for […]. Your point of contention is that there are other candidates that likewise provide ‘a’ necessary condition for […]. Hence, the Christian God is not ‘the’ necessary condition. In other words, the argument’s proponents need to establish that ‘only’ the Christian God is a valid candidate for the necessary preconditions. I don’t know how they propose to meet that burden, but is that the gist of it?

yes

You are choosing premises which are easy to disprove. It would be more honest intellectually if you used the types of premise which are normally used eg

1, If absolute Morality exists, then God must exist.

2. Absolute Morality exists.

3. Therefore God exists.

So I took a look Michael Butler's defence of TAG

http://butler-harris.org/tag/

and it seems to me that Van Til fails to establish a specifically Christian account of God as the necessary precondition. He seems to admit this in accepting Berkouwer's criticism that there is a lack of biblical exegesis in his writings.

Butler contends that Bahnsen, following Til, establishes the Christian account of God as the necessary precondition when he grounds presuppositional apologetics in the writings of Paul, who defines Christ as the source of all truth and knowledge.

From there, somewhat tortuously, we get the division of the world into a Christian and non Christian worldview, only from within the Christian worldview is God justified entirely internally. This obviously requires their specifically presuppositional justification of God. So given presuppostion only a Christian account of God grounds presupposition.

It seems circular.

As someone who thinks that TAG fails, I do think you can substitute other theistic conceptions in the argument without much difference in form or meaning. However, the actual proponents of the argument clearly don't. Van Til and Bahnsen are both very clear that this is not about a generic theism, but about the specific version associated with Christianity.

I think there are two motives/justifications for this claim. First, TAG is part of larger project whereby they mean to show that (their version of) Christianity is the only worldview which doesn't in some way contradict itself. So they will claim that since reasoning is never worldview-neutral--it is only the specific Christian worldview that is fully consistent (whether this can actually be demonstrated is, as pointed out by dereds, very unlikely).

Second, the specific epistemology of Van Til and his followers is explicitly based on the putative claim that they know that p because their reasoning is not merely human-based reasoning, but based on the authority of the Christian God through his revelation and witness. Of course, for that to work you have to be speaking about a specific iteration of God rather than just the generic concept.

If you think you can do a better job with that argument, fine go somewhere else and defend it.

As it is, you are wrong on three counts. First, I chose logic instead of morality because I've already dealt at length and in numerous threads with why the moral argument for the existence of god fails. Second, the focus on logic is very typical of presuppositionalists (e.g. in Bahnsen's debate with Stein, in Matt Slick's TAG, etc.). Third, I actually think the logic version is more difficult to deal with. Lots of people have thought about the foundations of morality and so are familiar with some popular alternatives to a specifically Christian or theist foundation, but few people are familiar with the various proposed foundations of logic.

Kind of. I would not want to agree that the Christian god may serve as a necessary condition for logic unless (like me) you reject S5 modal logic. However, it is true that most of my argumentation here has focused on the fact that there are viable alternative explanations for the foundation of logic that do not appeal to God.

Honestly, part of the reason I dislike TAG so much is that it seems to me like a cheat. Philosophers have raised some serious objections to the justifications of science (the problem of induction) and logic (circularity objections). There are various attempts to respond to these objections, none of which are really overwhelmingly convincing. What TAG proponents do is they use these objections to argue that there are insuperable problems with any non-theistic worldview. They then say that these problems don't exist for Christians as God would just make sure they weren't problems.

My most visceral response is to say, well, if I knew that was allowed I wouldn't have worried about these problems in the first place. So I am definitely not satisfied with the explanation for the foundation of logic given by presuppositionalists.

You threw yourself a very soft ball there with your premises in fact I'd say it takes away the efficacy of your argument. Slick uses logical absolutes which does make the argument more difficult.

Why are you prejudiced against softball? That is very offensive to softball players and fans. There is nothing wrong with wanting to play with a bigger ball.

What do they appeal to then?

A. There is at least one truth.

Do you affirm A? I do. And while the upper realms of logic aren’t necessarily common sense, its foundation seems to be.

I think this idea is central to my problem with your approach. You bring in the idea of necessity and base your refutation on attacking that. I can't entirely blame you if you're working from texts by people like Van Til and Bahnsen. They were both EXTREMELY dogmatic and often used words like "certain", "absolute", etc. But they were not basing their ideas on the traditional notion of God as a necessary being - at least TAG can be formulated in such a way that necessity isn't required.

I've tried to show that I don't think a good TAG argument needs to use those concepts. Along with Craig I think all a good argument needs to show is plausibility. Therefore you don't refute the argument by showing God isn't necessary (I'm not admitting you HAVE shown it, BTW, and I personally believe he is, though I don't base any arguments on that approach). If God is a good ground for logic (morality, science, knowledge, etc.) then that accomplishes one of the main premises of TAG. If you can't show a good ground for those things on atheism then TAG shows Christian theism is more plausible than atheism.

you don't need any argument to show plausibility, that will be conceded for free. That is obviously not the purpose of TAG and apologetics in general because plausibility isn't the issue. Necessity, proof, etc - that's the only part under contention.

Well, as I explained in my introductory posts, there are several different non-theistic explanations. The one I used as an example is conventionalism.

I don't really see what this has to do with the foundation of logic. Here, as with the foundations of math, the issue isn't so much solving problems as finding a semantic basis for logic or math claims and how to justify the basic principles of the fields.

I think of Van Til and Bahnsen (along with John Frame) as the most prominent proponents of this viewpoint, so I feel like I'm on pretty solid ground taking their presentation of the argument as canonical. I agree that they were "extremely dogmatic, etc," which is part of why I reject their argument. Seems like you agree with me, yes?

Also, if you think there is a version of TAG that doesn't require that we show that viable non-theistic explanations of morality, logic, or knowledge don't exist, feel free to spell it out or link to it here. This aspect seems essential to the logic of the argument to me.

Okay, first, I am not here trying to show that God isn't necessary in the "necessary being" sense. That subject is part of a different discussion in my opinion.

Second, as I've said elsewhere, I think your focus on replacing key terms with "plausible" is misplaced and unhelpful. The heart of TAG is not in showing that God is a plausible explanation for logic, morality, or knowledge. That is more or less assumed. Instead, it is in showing that there are no plausibly true non-Christian (or non-theistic) explanations for logic, morality, or knowledge. Since it is compatible with God being a plausible explanation for logic that some non-theistic explanation is also plausible, merely showing that God is a plausible explanation for logic gets you nowhere with this argument.

Third, you are just being lazy with the logic of the argument here. TAG refers to a specific kind of argument. It is right there in its name, "transcendental." This kind of argument is inspired by Kant and functions by showing not that x is true, but that x is a necessary precondition for something else and so assumed if we accept that other thing (Kant used this to explore the necessary preconditions for human experiences).

But you are talking about some other kind of argument, essentially an inference to the best explanation. Your argument is something like this: we have something that needs to be explained, e.g. morality or logic, and God is a good explanation for this thing and these other non-theistic explanations are kind of crap and so we should regard the existence of morality or logic as increasing the likelihood that God exists. Whatever the merits of that as an argument, it is just a completely different logical form than TAG.

The reason I'm stressing this is because I'm not talking about your inference to the best explanation argument in this thread. The argument I'm talking about has the transcendental argument structure. So maybe you think your argument succeeds. Fine. But what about TAG?

I would definitely NOT include Frame in the same class as VT and B. In his book, Cornelius Van Til, An Analysis of His Thought, Frame is highly critical of VT's hyperbole and overstatements, as well of his attacks on the motives of various theologians and philosophers. Though he called VT the most important theologian (not apologist) since Calvin, and which I think is wildly hyperbolic in itself, he had a lot of negatives concerning his rhetoric and other aspects of his material.

Here is what Frame says about VT's method and TAG:
I've quoted all this not to debate the content itself but to show how Frame understands TAG - that it isn't limited to Van Til's approach or his vocabulary. As I said before, the traditional theistic proofs have in common with TAG the idea that things like logic, morality and science can only make sense if they have their foundation in God. It is the fact and need of the foundation that are transcendental, not the form of the argument.

Oh, okay. I was thinking the argument would trail into something like ‘sapiential sense’ or the ‘nous’ as preconditions for logic.