Ok, I didn't find category for this argument (but I feel it's mostly connected with design, in this case design of logic, thence my category choice) and I'm very happy about this because this argument is probably the worst possible try ever to smuggle god as a required presupposition. Yet I know that many people still use it, and I know that most people have problem with pointing what's wrong with it, so I wan't to say my piece in the topic. And it's not going to be long.

Argument basically says that existece and validity of logic presuppose the existence of god. And basically that's it. You're not going to hear much of a further explonation other than "God is required for validity of logic, without god you can't know whether your logic and your conclusions are correct". In some other forms we may hear about knowledge or reason instead of logic, but validity of reason is based on validty of logic and validty of knowledge is based upon validty of reason, so it all comes down to logic.

And here is why it's wrong, and why we're bond to presuppose logic:

Normal person do this: Presupposes logic and builds upon that.

Presuppositionalist presupposes god and builds upon this.

But to build anything, to draw any conclusion logic must be valid. In other words presuppositionalist must presuppose logic anyway. Logic must be valid if we want to say "God exists therefore X"

But since presuppositionalist tries to justify logic all they efforts come down to "let's presuppose validity of logic in order to prove validity of logic. That's most absurdal form of circular reasoning you can ever hear.

So final form looks like that:

Let's presuppose god exists and logic is valid. Validity of logic and existence of god prove validty of logic. Voila, we proved validity of logic!

Then you're most likely to hear "How do you know it? Without god you can't know ebcause god is foundation of logic" But that's as if someone discussed whether god exists or not and then said "god exists because god exists, I won"

You see a grammar or spelling error in my post? Feel free to point it out, I'm still learning.



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The presuppositional school of apologetics is based on circular reasoning which is a huge problem.  I think they do a good a good job in pointing out the noetic effects of sin and all Christian apologists should carefully take that into consideration when presenting a reasonable defense of theism.  However, the magisterial and ministerial use of reason solves that problem.  At bottom, and I have a lot of experience dealing with presuppositional apologists, they are Kantian transcendental idealists.



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I suppose this amounts to, “You have to use logic to show God is required for logic.” It wouldn’t necessarily be circular, because you’d be using the logic God made possible, to prove that God made logic possible. Yet there must be genuine evidence outside this circle, arguments made using logic that are more than pointing fingers or waving hands.

I think logic exists independently from God, but that God was required for anyone to think logically. I don’t think God created the laws of nature, but that what we’re seeing in nature is the result of what God could do, in the process of creating nature. God can leave it alone, to a certain extent, and the laws abide, perhaps with human observers. One and one still equal two, even if someone only checks now and then. Categories of things exist, and true or false propositions can be generated from the categories, as we get around to it.

There are two more things I’d like to relate in this context. First, at no time in history has anyone inquired seriously into the mind, cataloging its powers and identifying the source and use of these powers. This requires an unheralded degree of introspection, even beyond the boasts about enlightenment in the East. There’s even a battle going on that some believe consciousness has a material (biochemical, neurological) cause, and this battle only occurs because the religions never touched this critical topic in serious depths. To think logically is actually a miracle, and one almost certainly not a result of evolution.

Second, God laments that He could not use logic in the religions, for the human entities are not ready. By rights God should merely need to say, “You are all created souls, now in the bodies of intelligence. I expect you to use this intelligence to dwell harmoniously and joyfully, optimizing the globe.” After hearing this and seeing its truth, the wise humans never make war or even quarrel again, mastering their minds and situations with power! In reality humans cannot accept this proposition, despite its inerrant logic. They also cannot accept any of the corollary or supporting propositions, that would make such a harmonious situation practically possible. Men are not logical enough to become good.


Tom Paine

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This argument amounts to saying "You have to presuppose my conclusion before you can argue against my conclusion, so I win." The problem is it's just a bald assertion. The existence of logic makes perfect sense as being a product of evolutionary forces. Logic is just mental algorithms that help produce novel true conclusions from input propositions. The survival value of being able to make more accurate predictions and build more accurate mental models should be obvious. This point completely undercuts their argument, if you can even call it that. It's really just an assertion.



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Logic is just mental algorithms that help produce novel true conclusions from input propositions. The survival value of being able to make more accurate predictions and build more accurate mental models should be obvious.
It sounds like you’ve become a Buddhist, more or less repeating the Buddha’s conclusion that men are nothing more than a “field of forces.” That’s what I’ve seen too. I haven’t met any “real persons,” who knew themselves to be more than a mere reaction to the senses, or even any that wanted to know this. Importantly the logic which drives the human plane is based on a presumption objects have inherent value, that the higher logic denies. So what is logical for a sinner, is not logical for someone who’s gone beyond sin.

I can add in here that you do not know what the mind is, nor do you care. You do not know what a thought is, nor do you care. You use the phrase “mental model” but really don’t know what it can mean, in essential terms. You’re like the driver of a car who knows where the steering wheel and accelerator are, but who doesn’t believe in an engine and has no curiosity about it either. If this is not so, tell me what a thought is, how it abides within you, how you are able to select memories and how you assemble sentences.