A few months ago I was challenged by a theist to a formal written debate on the existence of god over on a theological website called theologyweb. I accepted. We agreed that he would make the opening arguments and make a positive case first and that we'd be debating the existence of a theistic god and not merely a deistic one (because theists have this tendency to retreat into deism when the going gets tough and I hate that). After my response back in June he never got back to me, eventually saying that he was busy with work and other things. So the debate is just sitting there, now closed, with only our initial opening arguments. I took the time in my opener to rebut my opponent's arguments. This is how I like to debate since atheists are often accused of not addressing their opponent's arguments, and in the hundreds of god debates I've watched, there is some truth to this.
My opponent, who on the website goes by the name of "LaplacesDemon" (LD for short), used the fine tuning argument as part of his case for god. And I just noticed that I have not written about the fine tuning argument as much as I should have. So below I have my response to LD rebutting the fine tuning argument. You can see the whole debate here, but you might need to log onto the site for access.
The FTA (fine tuning argument) is in my opinion the only halfway decent argument for god. But even if granted, it doesn’t lead one to conclude the existence that theism is true any more than deism, or that the universe is a computer simulation. In fact, if the universe is fine tuned, those two options are overwhelmingly more probable than theism. And I will argue why.
I’m not going to dispute the parameters LD mentioned even though a few of them are a bit off because almost all scientists agree that the life permitting range for those values is very narrow. What I will instead argue is that the apparent fine tuning is better supportive of atheism, not theism.
i) The FTA makes it seem as if god himself is constrained by the laws of physics. LD even writes, “if gravity did not exist ... intelligent life would be impossible.” Why does god need to fine tune anything? Are you telling me there is only one way god can create a universe with life in it? That would be like saying there’s only one way god can make a cake because he’s constrained by the directions on the box. God is supposed to be able to do anything logically possible, so he should be able to create life via perpetual miracles in conditions where life wouldn’t otherwise be able to exist. If the universe didn’t have its life-permitting parameters and yet life still existed, that would be better evidence for god. Or if the earth was literally the center of the universe, that would be evidence for god. Such is not the case.
ii) The fact that life on earth exists on such a knife’s edge whereby the slightest change can be catastrophic leads many atheists to conclude that the universe is not fine tuned for human beings. The haphazard cruelty of evolution makes it impossible to accept the belief in a traditional omni-god who is all-knowing, all-powerful and all-loving. When you look at the full picture of evolution and you consider the 3.5 billion years during which this unfolding drama played out, when there were millions and millions of species that evolved only to be snuffed out and pushed into evolutionary dead ends, and during which time there was at least 5 mass extinctions in which some 70-95 percent of all the living species on earth at that time went extinct, I'm being asked by theists to believe that this was all part of a divine creator's plan who was sitting back and taking pleasure in watching millions of species (whose evolution he allegedly guided) get wiped out one after the other, and then starting all over again, and then wiped them out again and repeated this process over and over, until finally getting around to evolving human beings – which I'm told was the whole purpose of this cruel and clumsy process.
There is no way I can believe that. I’m not just arguing that the existence of evolution’s cruelty makes god improbable, I’m arguing the two are logically incompatible. Grant a designer to the universe and you must grant that that designer is either totally incompetent, totally indifferent, or totally cruel. There is no logical way of it. Thus the god of classical theism - which we are debating - is logically impossible given our universe.
iii) The apparent fine tuning of the universe can be explained by chance given the multiverse hypothesis. If there are an extremely large number of universes, then our universe’s hospitable conditions can be explained in the same way that our planet’s hospitable conditions can be explained - there are a lot of planets, and through sheer chance some will be just the right distance from its star to support life. Given the fact that the multiverse was originally derived from inflationary theory, not some ad-hoc explanation to refute the fine tuning, and that recent data strongly indicates inflationary theory is correct, we have very good scientific reasons to believe our universe is not alone.
The scale of the universe, the insignificance humans play in it, the multi-billion year cosmic evolution, the multi-billion year haphazard cruelty of the evolutionary process, and the strong evidence we have that the multiverse is probable all seem more likely given chance under the atheistic worldview as opposed to theism. The theist here must argue skeptical theism, and therefore puts themselves in an epistemic handicap when it comes to knowing anything about god. For if skeptical theism is true and we’re in no position to tell why god has allowed evil and suffering, then if someone were to see a person (or animal) suffering, it's possible for one to reason that it's all part of god's plan that in the end will make sense and that they should not interfere. This, as we can imagine, could lead to indifference towards moral evil and natural suffering.
Every argument from design has essentially got it ass-backwards, to use a colloquial term. Our hands were not designed to grasp bananas or iPhones, rather, they were designed to fit our hands. Our universe (and indeed our bodies) could have been designed better. Physicist Don Page, who is an evangelical Christian, argues that if the cosmological constant were zero, or a negative number, “the fraction of baryons that condense into galaxies that in turn form living organisms would be higher” and that this “result thus gives a preliminary suggestion that there might eventually be evidence against optimal ﬁne tuning for life”. But I expect LD to argue that god is an artist, not an engineer, and so god is free to create humans anyway he wants, fast or slow, because god “wants to splash his canvas with extravagance of design” to quote William Lane Craig. But what kind of artist would use sentient beings as his material and sit back and watch them suffer and die for no logically necessary purpose for millions of years? Not an all-loving god that’s for sure.