Name of fallacy that argues against the tools necessary for the argument

Question

Let's say that someone believes that philosophy in itself is a bad thing. If I'm correct, the only way to combat this premise is to use philosophy (which is off limits since it's on trial)!

Similarly, (a real example) a Christian writer publishes a book on why theology and theologians have done all they can to ruin Christianity (allegedly muddling up the "simplicity" of Jesus' teachings) and therefore, theology is bad. This is clearly a theological stance and the only way to combat it is with theology...

Am I seeing something that isn't there?

Does anyone know the name of this fallacious argument? It seems to shut the debate down before it even starts. Does anybody have any other examples of this besides theology?

Answer 1

It's not a fallacy, it's simply that in cases such as "is philosophy a good way of reasoning ?" or "is logic valid ?", there is no debate to have, and all you can hope to do is make sense, in your system, of why your system is good; it's not possible to do it outside of the system anyways. I think a philosophy teacher of mine once answered this question with a "quote from Aristotle" (this seems very suspicious, but it doesn't matter who first said it; moreover I'm only paraphrasing here): arguing with someone who doesn't value logic as a valid way of reasoning is useless: it would be like reasoning with a vegetable.

Answer 2

I wouldn't say your example is really fallacious. Theology is usually understood to mean the activity of systematizing and theorizing about religious doctines, and your writer may be objecting that all such systematizing is unhelpful. If the writer is unwilling to debate whether and why it is unhelpful, or give reasons for thinking so, that would be a separate issue. It is always good to have reasons.

As to there being other examples, Wittgenstein in proposition 6 of the Tractatus gives an account of the relationship between language and the world. He concludes that any such account is impossible because it lacks sense and therefore the whole project of philosophy should be abandoned. If the reader is inclined to ask, what is the point of the Tractatus then, since it is a book of philosophy? Wittgenstein's answer is to compare it to a ladder that you kick away after you have climbed it.

It is not fallacious to provide reasons as to why reasoning (at least of a certain kind) is useless. It can be understood as a kind of reductio ad absurdam argument in which not the premises but the very reasoning itself is self-defeating and should therefore be discarded.