The fine-tuning argument for God's existence is a failure

I accept my opponent's conditions. As a courtesy, however, I will present a basic representation of my argument from fine-tuning. My opponent's burden, then, will be to show how my argument does not make the existence of God at least slightly more probable than whatever the probability may be without it. I will be arguing that the fine-tuning of the universe is significantly more probable on theism than on an atheistic single universe hypothesis. And, if necessary, I will be arguing that the Multiverse hypothesis fails the rule of parsimony inasmuch as it posits an infinite amount of necessarily unobserved entities. That is to say, it multiplies entities beyond necessity. My basic, employed probability calculus on this issue, given in Bayesian terms, is as follows: PR (FT/T) >> PR (FT/ASU) Where "FT" represents fine-tuning and "T" represents theism, this calculus asserts that, given theism, the probability of "FT" is greater than when "ASU" (atheist single universe hypothesis) is given. Of course, this probability calculus presupposes that the universe is, in fact, finely tuned. I will not argue this point unless my opponent chooses to deny its existence. I will, however, clarify what it is I mean by fine-tuning. What is Fine-Tuning? When I say fine-tuning, I do not just mean the universe is ordered in such a complex way, delicately balanced upon a razor's edge, as to allow for the existence of intelligent life - thought it is, of course. Rather, I will argue that the universe and all its constants and conditions, under the principle of indifference, could have been different. That is to say, there are innumerable alternative and equally as probable constants and conditions that could have occurred during or after the formation processes of the universe starting from and during the Big Bang. There are, on the other hand, very few outcomes that would permit a sustainable universe where anything at all is operable. The very existence of our universe requires finely tuned constants and conditions. Given solely unguided and natural processes, however, the probability of an operable universe, like ours, is very low. However, the probability of an ordered, intricate and operable universe given theism, or at bare minimum, intelligence, is very high. Does This Argument Fail? Per my opponent's definition, this argument fails if, and only if, "the argument does nothing to make what it is arguing for more probable or plausible." This seems quite a difficult thing to do. It certainly seems clear, especially considering the prime principle of confirmation, that observed complexity is more likely on "T" than on "ASU." Perhaps what my opponent meant by failed was that the argument does nothing IF it is false. But that is obvious and goes without saying. So instead, my opponent must show that my argument is necessarily a non sequitur, inasmuch as the probability of theism is not increased even if all my premises are true. We will have to wait and see the approach my opponent takes. So far as I can see, observed and ordered complexity are more probable on theism than on an atheistic single universe hypothesis. For instance, if I walked in the woods and saw a fully assembled log cabin, I would not insist that the trees happened to fall in such a way as to construct the cabin – I would rightly posit a designer – even if he be unobserved. Given the principle of indifference, as stated above, however, each outcome, including the fully assembled log cabin, was equally as probable under "ASU." In order for somebody to explain the log cabin without positing a designer, they would have to posit numerous assumptions and unobserved phenomena. On "T", though, we have very good reasons for believing that the universe would exist in an ordered, habitable and operable fashion. Which is more parsimonious? Which, my friends, is more likely? I hope this will give my opponent an understanding of my position so that he may build his own accordingly. InquireTruth