Why not...
Max Atheist: I just presuppose the uniformity of nature and the laws of logic and objective moral values, that's why I can engage in scientific inquiry and write philosophy papers and go to political protests.
As I said, this is a category error. Presupposing the proposition "science is intelligible" does not make science is intelligible, for you have to explain
how it is. Not any proposition can be a presupposition. For instance:
Presupper -- Given my worldview, which presupposes God as the ultimate transcendent authority, I can make sense of science, for I have a good reason to believe that nature is uniform [because of a sovereign and immutable God who controls all of nature uniformly], that an objective universe exists [because a single God actually created it, per Gen. 1], that our senses our reliable [because they were created by a trustworthy God], etc. Scripture tells me all this.
Atheist -- Well, I just presuppose all those things by themselves without invoking God.
Presupper -- Those propositions which you are claiming to presuppose are corollaries of other propositions, and consequently they are
provable or
disprovable [since they can either be implied by something else or not]; therefore, they cannot be presuppositions, since presuppositions by definition cannot be
proven or
disproven by some other proposition other than themselves. Moreover, those propositions do not logically imply each other (e.g., "Nature is uniform" does not logically entail "Moral values exist"), and therefore each of those propositions cannot be a presupposition, lest you want to have several worldviews, all of which are incomplete. This is absurd. [That is the "floating pillars" fallacy.]
Atheist -- Well, why does God count as a presupposition, then? I have seen several disproofs of Him.
Presupper -- Some arguments attempt to disprove an immanent god, different from the God of the Bible. Such arguments try to show evidence of evolution which contradicts Genesis, but that only works because of a pre-established materialistic consistency. The only arguments which are not
prima facie illegitimate are ones which attempt to disprove God by positing a logical inconsistency in Him (e.g.
this), and that is because God is transcendent. Therefore, in order to have a true presupposition, you must have one which can only be destroyed from the inside.
Atheist -- Alright, sign me up.
By the way, the last response of the presuppositionalist is not at all inconsistent with the other article I provided ("The Necessity of External Consistency in Apologetics"), for I am not positing external consistency with some "neutral" facts which we acquire apart from our presuppositions. Rather, what I am positing is some undeniable facts which simply cannot be disbelieved (surely by God's common grace/providential benevolence), and therefore which are
necessarily contained within a presupposition. Thus, the "undeniable facts" which I spoke about are not facts by themselves which we start with and then work our way towards a presupposition -- that is not the method at all -- rather, these facts are so undeniable that whatever worldview we have
must include such facts as part of it, and that is how we point we out internal inconsistencies.