"Hey, I still don't understand why someone cannot choose non-christian presuppositions and establish a "coherent worldview".
Theoretically you can, but: (1) it can’t be atheism because atheistic worldviews are internally self-contradictory and (2) if you can, please bring forth *that* particular theoretical, self-consistent worldview and show how it contains within itself the sufficient preconditions for the intelligibility of reality.
"Why can't I just presuppose the existence and correctness of absolute laws of logic?"
This is a good question and I will take time to offer a response. You can simply presuppose the existence and correctness of absolute laws. However, if you do (presuming that you’re an atheist, please forgive me if I have you labeled incorrectly) you will be irrational and internally contradictory. Please let me explain.
I. I believe that irrationality will follow because you’re simply presupposing without epistemic warrant the uniformity of logical laws via a vicious circularity. We can presuppose the uniformity of logical law (hence appealing to rationality contained with creation) because God Himself declared that there will be uniformity found within the created order, including the laws of logic (Gen. 8:22 – an appeal to mystery as contained within the mind of God). If you are an atheist, you have no such authoritative declaration, but must assert with mere probability that future instances of past events will occur in the future as they have in the past. This is a fine example of circular reasoning. Also, you will show that you are working off of a type of faith as well (albeit a drastically different one from the Christian conception thereof) because you are merely assuming that the laws of logic will behave in the future as they have in the past without any epistemic warrant.
As an aside, I took note that you used the descriptor, “the correctness of absolute laws” to refer to logical laws. Assuming that we try to understand the universe through the worldview of philosophical materialism, it is logically impossible to have both absolute, unchanging, and immaterial logical laws being derived from a non-absolute, continuously changing, material universe consisting of only particular entities.
"How do you account for the existence of God? I'm sure you will say you don't need to because it’s your presupposition, ie. what you take for granted. Why can't I do the same maneuver with the laws of logic?"
II. Again you can (and do) take the laws of logic for granted, but you have no rational reasons for expecting the uniformity of logical law. If you are a naturalist, you’ll simply presuppose it a priori in a similar way that we presuppose the Triune God a priori because he is the final locus of authority for us as Christians. The final locus of authority for you will consist of your own brain. From our drastically different perspectives, we have no higher authority upon which to turn. We turn to the authority of the Triune God, you turn to the authority of your finite brain.
III. We have continually asked the materialist to give an account for the most basic laws of nature to which you have essentially responded, “I can’t. No explanation exists for the most fundamental, presupposed, and ultimate regularities of life and reality. There is no regularity about the most basic regularity because there is no law in terms of which the basic law can be accounted for.” So, you are assuming that the laws of logic and the laws of nature are the most basic, presupposed, foundational principles of reality in an atomistic sense, meaning that there is nothing more ultimate that you can turn to other than the basic laws of nature because there is nothing at the base of them. This rational maneuver of atomizing things, that is, analyzing things in terms of their most basic components or laws by which the universe operates has to end somewhere for you, and when it ends, your basic laws have no explanation at all. Given your position, the most basic laws themselves cannot be accounted for because they are ultimate. This is certainly understandable given your atomism.
So, how do we know these basic laws and how do we explain them at all? Why are they the way that they are? In answering questions like these an atomistic rationalist will end up doing the very thing he is trying to avoid, which is appealing to mystery. Why is this a problem for you? Because when you make an appeal to mystery it ruins your entire worldview, for you desire to rest your views on what you perceive to be a rational, empirical explanation, yet at the base of it, it is rooted in mysticism, the very thing you seek to avoid and the very opposite of what scientific rationalism claims to be. Here is the rational system of scientific, empirical explanation ultimately resting on a foundation of mysticism, the thing which is the very opposite of what it claims to be. Science and mysticism are supposed to be poles apart, but it turns out that scientific rationalists are mystics at base. So, when you are asked to account for the existence of logical laws/scientific laws apart from God, your response ultimately reduces to this answer: “They just are as they are”. Hence, you show that you believe that the basics just are as they are. According to your understanding, it’s just some kind of mystical, positive, reality that cannot be explained.
But the Christian is not reduced to a dialectical tension consisting of a rationalism and a mysticism that are at odds with each other within the same worldview. When we appeal to mystery, it’s mystery because we say, “Our finite minds cannot account for it” and “It’s mystery because we only know this because we are depending upon the special revelation of God.” The sense of mystery, or if you will “irrationalism” in Christianity is that it appeals to that which goes beyond the finite human mind. You do the same thing, you just don’t appeal to God. You stop short of that by appealing to a lucky mystery based upon the chance happenings of the evolved universe. So, the rational/irrational internal tension remains strong within your worldview. However, when we appeal to the revelation of God we don’t do so at the expense of our rationalism, but instead this becomes the very foundation of our rationalism. Because God is the divine regulator and orderer, His mind is reflected in creation, and as a result, He has given us a mind and the necessary laws by which we *can* reason in the first place (i.e., the laws of logic, etc.).And so, the atomistic, scientific rationalist, has to explain his basic laws in terms of just the “mystical positive of chance”, but that’s just the very antithesis of scientific rationalism and empiricism. However, the Christian, by appealing to the mind of God as understood in the Scriptures, can account for all the regularities and order of the universe without giving up his rationalism. And so, if you compare the two worldviews, you see the dialectical tension of the one, and the harmony of the other, and by way of conclusion, I think that such internal contradictions within the unbelieving systems of thought reveals what the Apostle Paul had in mind when he said that the unbeliever continually “opposes himself” (2 Tim. 2:25).