Here is a blog post I wrote a few years ago:

http://provingchristianity.wordpress.com

The argument is invalid. Here are a few objections.

1. At most, the argument proves that logic requires theism. The elements of Christianity you cite as necessary for logic are also accepted within Judaism and Islam.

2. This is a reductio argument for theism, but in fact many people accept the so-called absurd conclusion and don't seem clearly inconsistent in doing so. For instance, Pyrrhonian skeptics do not believe we know anything, and so accept that we are missing the preconditions to prove anything. Zen Buddhists reject the ability of language and analytical reasoning to prove the most basic truths about the universe.

3. The argument fails on its own terms. It says that the Christian worldview is the precondition for knowing anything, and attempts to prove this by arguing that logic is necessary for knowledge and only the Christian worldview can justify logic. However, it doesn't follow from this argument that either Christianity is true or that we can use logic to gain knowledge. Instead, this just pushes back our lack of knowledge regarding the justification for the laws of logic to a lack of knowledge about Christianity is true.

For instance, I can claim it is a precondition of Sherlock Holmes existing that he was born, but this claim is neither a proof that Sherlock Holmes existed or was born.

4. I challenge the claim that only a theistic (let alone Christian) worldview is coherent with the claim that logic is universal, immaterial, and unchanging. For instance, the Platonic theory of Forms also conceives of logic having these characteristics, but without appeal to a god.

Can you expand on the specifics of this a bit, or link a good link that explains well these specific parts of these belief systems? I've been trying to find a home within established philosophical identities forEVer now, and this might help.

I actually think that this is the best argument of the four that you listed.

I am basically defending a version of the Transcendental Argument for the Existence of God (TAG). TAG was first popularized by Cornelius Van Til, and later by Greg Bahnsen.

A one-sentence expression of TAG would be: "The proof that Christianity is true is that if Christianity isn't true, one can't prove anything at all."

Even more succinctly: Christianity or Nilihism.

So a "defeater" to TAG being a literal proof of Christianity would be to say that one can't know anything. But, saying one can't know anything is itself a truth claim, so....

I think my response to your #2 might apply here as well.

Jesus as the logos is an important component of TAG. I will develop that idea in a later post.

As always, OP, thank you for your thoughtful response.

It should be Christianity or Skepticism, right? However, neither Pyrrhonian skeptics and Zen Buddhists assert that we can't know anything, so they avoid the inconsistency you cite here (at least when they are being careful).

I don't see how. My point is that we can only justify that we know the laws of logic are true by citing Christianity if we have a prior justified belief in Christianity. Which we don't. Thus, we are left with am unjustified belief in Christianity rather than an unjustified belief in logic. How is that a significantly more rational basis to thought?

You might be interested in this prior thread on TAG.

https://forumserver.twoplustwo.com/1...youre-1342164/

Trying to prove Christianity is true solely through argumentation is to only see it as a static, top down system. It’s missing the bottom up, transformational aspect as a separate component rather than simply a result of top down propositional beliefs.

To be fair, it’s an inevitable error since the bottom up process is intuitive and hidden.

I stopped reading there.

I take it you are unfamiliar with Presuppositional Apologetics? It is a common apologetical method employed mostly by Calvinists.

Thanks, I'll check it out.

I've seen arguments of this type before. I've never found them to be remotely convincing. The crux(!) of Christianity is the death and resurrection of Jesus. Without it, there's no Christianity. But I don't see how the death and resurrection of Jesus has any implications on the structures of logic.

As OrP said, at best it seems you don't get beyond theism.

Philosophy is about investigating the nature of knowledge and "reality" ... not about gimmicking up arguments to defend already held positions. One can presupp for any god, any belief, anything real or imagined. Invalid. It's okay to be under the sway of indoctrination, and it's heroic to move out of it.

Pyrrhonism is the name of an ancient skeptical school of thought that denied that we know anything. Here is the IEP on it or ask if you have a more specific question.

Zen Buddhism is a version of Japanese Buddhism that teaches that our attempt to understand the nature through reason and logic is inevitably flawed because the process of reasoning itself acts as way of separating our mind from what we are reasoning about and so disguises the fundamental connectedness of all things. It instead argues that various forms of meditation causes us to gain actual understanding of the universe.

Thanks for responding. I know it's not your responsibility to satisfy my curiosity, but the deafening silence was a bit hurtful. (<-- tongue-in-cheek. But also: srsly.)

I did read up a bit after the previous comment, but wasn't interested in historical background so much as I was hoping for a concise and easy-to-swallow explanation as to this specific idea of why we can't know anything.

Bolded is more of what I was looking for but it's still not as clear as I'd hoped. Especially given that I'm not convinced of qualifying italics. And also the fact that it seems difficult to use logic and reason to explain why reason and logic are flawed. People like to talk about self-defeating arguments, but to my ear it seems like the only thing to say is that "if logic and reason are flawed, then [this is all gibberish, and what the hell are we even talking about anyway!?!?]" i.e.: nothing is refuted, but neither is anything accepted. Although I think given that we do appear to be communicating, and that our experience of the Newtonian mechanical world seems to more or less match our reasonable expectations, then we can perhaps accept some usefulness of logic and reason on a provisional basis, even if we don't extend that to absolute epistemological truth.

Was just wondering how this is approached in more formal philosophical views. Skepticism at first glance sounds like it could be up my alley, but then I read about it and at some point they seem overly concerned with what is "good", and what certain actions do to your "soul", and stuff like that. Does not compute. Your link is different though than the one I stumbled on myself the other day, so I'll give it a read when I have a moment. I ctrl-f'd out of curiosity and they don't mention the soul once, so that's a good start.

EDIT: Oops, forgot all quotes are italics. By "qualifying italics" I just meant the part where we assume some meaningful connectedness between all things and also that mediation necessarily provides more meaningful answers.

Excuse my cutting in between.

He doesn’t seem to be using ‘true’ as historically factual. His proof that Christianity is true I interpret as an attempt to prove that Christianity most accurately reflects reality from a phenomenological perspective.

In my view, accurately reflecting reality is a higher truth (religiously/philosophically speaking) than historical fact but is still missing the moral element. As human beings, our highest desire is not solely to perceive reality accurately but to move toward, align with, embody, and perpetuate life (or the good). That is what is most true. Christianity seems to have stagnated in proving it is true in that sense.

The death and resurrection of Jesus are indeed NECESSARY historical events for Christianity to be true. But not SUFFICIENT. His claim to be God incarnate, and that it is only through His death on the cross that our sins can be forgiven are also NECESSARY.

In short, it is both the ACTIONS of Jesus AND His CLAIMS ABOUT HIMSELF that are the crux of Christianity.

Okay. I didn't say that there wasn't a logic to Christianity.

But that doesn't have any implications on the structures of logic. That is, whether Jesus is the Son of God doesn't imply anything about whether modus ponens is valid logic.

The presuppositionalist perspective, which states that without God there isn't even a valid logical form does not hinge on Christology. It hinges on the assumption (presupposition) of a logical God that set the universe in order.

God said to Abraham, essentially, slice off part of your penis for me.

To worship that "god" is to worship a demon.

No, He didn't.

No, it isn't.

If you stop lying, maybe a conversation can be had.

I don’t think anyone is supposed to be able to prove or disprove Christianity, it’s a faith based religion w mysteries.

When did you first discover presuppositional apologetics - after you were already a Christian, right?

As is common with apologetics, you're presenting something that had no bearing on why you actually became a Christian, and in this case requires someone to already be a Christian in order to accept it (in fact not just a Christian, but probably a Calvinist - and even most other non-Calvinist Christians reject it!).

Just curious how you'd respond
I always got the impression that those who employ it had been unable to satisfactorily defend their faith (to others) through evidential means, and this <i>appeared</i> to be a show-stopper.

PS Are you aware that the core part of the presuppositional apologetic, that only the Christian worldview can account for these 'transendentals', is the part that remains deafeningly unsupported?

Hey lagtight, Im just posting what comes to my mind when hearing logic and proof on such big matters:

https://en.wikipedia.org/wiki/Axiomatic_system
https://en.wikipedia.org/wiki/G%C3%B...eness_theorems
https://en.wikipedia.org/wiki/Law_of_noncontradiction

To your Green/Red Light annecdote:
"I'm a liar" => if true, Im not a liar so the argument is false as I did in fact just lie.
"I'm a liar" => if false, I actually just lied so the argument is false because I was telling the truth.

Have to admit I just skimmed your text and only posted the links because I dont have time at hand to formulate myself right now. Hope it strenghtens your argument or helps you find a better one if your argument becomes void. Very happy to discuss this further if you are into it.