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

The story so farIf the probability of getting a life permitting universe given atheism is inscrutable, the fine tuning argument fails. To support my claim of inscrutability, I have shown that our epistemically illuminated range is far smaller than the probability space, and so the frequency of life permitting universes in our sample is no guide for the frequency across this all-but-unknown space. CON offers a smorgasbord of counter-principles, analogies, and reductios as to why this is mistaken. All, sadly, are products of misunderstanding. Here, I'll show these misunderstandings, salvage the arguments CON uses from his mistakes - and then show these arguments fail anyway.k' is not background knowledgeCON writes, "k' stands for our background knowledge." I disagree ("k' = our background knowledge, subtracting knowledge of our existence or this universe existing.") So does Collins: "[W]e cannot simply take k′ to be our entire background information k, since k includes the fact that we exist, and hence entails LPU." (Collins, 2009, pp.241) To my knowledge, so does all the literature.If we include all our background information, P(LPU|k) = 1 by the weak anthropic principle - so P(LPU|k&ASU) or P(LPU|k&T) will be 1 too. The is the old evidence problem. The solution Collins borrows (and I accept) is we need to subtract out the background information of our observation of an LPU, giving us k' (cf. {3} above). CON is just wrong here, and his later assertions ("Since k' includes both our epistemically illuminated range (EI) and fine-tuning (FT)...", "What we do not know is necessarily not part of our background knowledge as it is, by definition, not knowledge.") are, to the degree I decipher them, hopelessly confused.We can use our normal background knowledge normally CON attempts a reductio to general scepticism by pointing to the a vast field of epistemic possibilities where a sceptical hypothesis is true (brain-in-a-vat, Cartesian demon, etc). Given I accept the frequency of these worlds is inscrutable, doesn't my argument oblige me to say the truth of any sceptical hypotheses is inscrutable?Firstly I can use k, not k' - I can keep in background knowledge about existing in this universe. Secondly, I need not apply indifference: I can deem the infinitely possible worlds where a sceptical hypothesis is true as very remote possibilities, instead of equiprobable with the actual world.{6} The fine-tuning argument needs both subtraction and indifference to work, so cannot escape the sceptical trap as I did. My sceptical concerns are selectively toxic to the fine tuning argument, and so this reductio falls flat.No good reason for EIR restrictionThe centrepiece of CON's case is to justify restricting ourselves to the epistemically illuminated range (EIR) with the fine-tuning argument. CON writes, "It seems practically common sense that we should only consider what is possible to consider when dealing with any sort of study, scientific or otherwise." Three counter-examples:Statistical significance: "My sample suggests X, but my sample is too small to reliably represent the population at large. These results are of no great significance"Skeptical Theism: "There are many evils that appear gratuitous. However, we should not believe they really are: there are likely goods beyond our ken we cannot consider that justify these evils."Argument from sceptical hypothesis: "It is impossible to know whether or not you are a brain in a vat. If you are a brain in a vat, this table does not really exist. Therefore, it is impossible to know whether or not this table really exists."If CON was right, we could dismiss these out of hand. He is not: the sensible thing to do when one realizes the truth of a proposition hinges on things one is unable to consider is to deem it inscrutable. In the case where our EIR is much smaller than the entire range, P(LPU|ASU&k') is almost wholly dependant on what we cannot evaluate - the frequency of life permitting universes outside the EIR. We should therefore deem P(LPU|ASU&k') inscrutable.CON then offers the partly illuminated dartboard from Collins (cf. Leslie, 1989). CON presents this in a manner reliant on his prior reductio and assertion that it is 'practically common sense' to restrict ourselves to the EIR. I have defeated these above. For extra brownie points, here's why the dartboard analogy fails to help CON's case.CON is right to say that hitting a bullseye confirms a bullseye aiming hypothesis, even in the worst case scenario of 'polka dot' bullseyes outside the epistemic range. Bullseyes are rare regardless of the state of the rest of the unilluminated region, so P(BI|C&k') is low.If Theism predicted a 'bullseye' LPU, the fine tuning argument could side-step my sceptical concern in the same way. But the fine tuning argument does not predict a bullseye LPU, but rather just an LPU. The appropriate dartboard analogy is not 'aiming for bullseye' but 'red selection'. Unlike aiming, our likelihood of picking red by chance is sensitive to how common redness is outside our illuminated range, and the sceptical argument runs as before.{7}Could we change the fine tuning argument to use a 'bullseye LPU' instead? The probability of landing in a bullseye LPU given Atheism is low, regardless of the limits of the EIR. Unfortunately, such a move switches the inscrutability to the other side: I'm willing to say that an LPU given Theism is not too surprising, but a bullseye LPU on Theism is inscrutable. So this variant of the argument fails too.EIR and probabilistic tensionHaving shown all elements of CONs case for EIR restriction fail, I now show why EIR restriction should be rejected.Collins talks elsewhere about probabilistic tension - one should avoiding holding conjunctions of beliefs where one is unlikely given the others (see (Collins, 2009. pp.209-210)) Collins deploys this to block the Atheist move of "okay, P(LPU|ASU&k') is low, but P(LPU|ASU&e&k') is not low, where e is some anthrophilic extension, and I believe ASU&e". If P(e|ASU&k') is low, then this is under probabilistic tension, and should be rejected for collections of beliefs under less tension (e.g. ASU&k', or T&k'). This is a probabilistic gloss for why ad hoc-ness is bad.Call "our universe is in the EIR" Q. Is k'&Q under probabilistic tension? Yes: by the assumptions of the fine tuning argument (indifference, subtraction, etc.), P(Q|k') is just the area of the EIR over the total range of the possibility space. The EIR is a minute bullseye in this probability space. As this fraction is miniscule, P(Q|k') is miniscule, and thus the addition of Q to our background suffers gigantic probabilistic tension. It therefore should not be added to our background information.This makes intuitive sense. To consider fine tuning, we need to subtract away all knowledge of this universe existing, and simply consider the bare facts of the possibility space of all the ways a universe could be. Yet, once we have subtracted knowledge of this universe existing, we have no reason to presume the universe must be within epistemic range of this one.ConclusionCON has failed to defeat the sceptical concerns I present. These concerns show P(LPU|ASU&k') is inscrutable. Therefore the fine-tuning argument is a failure.{6} I may be mistaken to include the falsity of sceptical hypotheses in my background knowledge, or to deem possible worlds where sceptical hypotheses are true as remote. But neither of these conflict with the sceptical concerns raised against the fine tuning argument. {7} Collins uses the dartboard analogy as evidence for including EIR restriction in background. Doing so, he avers, is the best likelihood reconstruction for the analogy. The red selection counter shows my likelihood reconstruction (not needing EIR in background) is better than his (which does need EIR in background). These analogies do not make a case for EIR restriction.