Before I discuss the Argument from Moral Knowledge further it’s helpful to explain why I think the Fine-Tuning Argument for God isn’t so great an argument. Why the detour? I read other arguments for God that turn on our relationship to objective morals (Ganssle’s fine-turning argument based on the applicability of objective morals to humans, Richard Swinburne’s argument from moral awareness, William Lane Craig draws on Ganssle’s argument in his debate about objective morals and God with Walter Sinnott-Armstong). The discussion was always in terms of how probable that relationship would be on the assumption of theism or on the assumption of naturalism. I also couched the Argument from Moral Knowledge in probabilistic terms. Now I believe this a diminished representation of the Argument from Moral Knowledge and the Fine-Tuning Argument fails to convince for similar reasons.
First let me say more about what the Fine-Tuning Argument is. Our best cosmological physics provides no reasons for why an electron should be 1/1836th the mass of a proton, why gravity should be such an absurdly weak force (far weaker than the weak force!), and so on for other fundamental physical constants. These constants could have taken on innumerable other values and for the vast majority of combinations a universe with stars and galaxies would not be possible, let alone one that harbors sentient life. So it is highly improbable that we exist on the assumption of naturalism. But on the assumption of theism, God would likely “tune” physical constants to allow for sentient life. So theism better explains our existence than naturalism.
One response is to ask how likely it is that sentient life like us really is on the assumption of theism. Because the question here is not how likely sentient life in general is, but how likely humans are because the only clear case of sentient life we have is humans. As Paul Draper writes, “Examined from the perspective of what is possible for an omnipotent being, we are, in terms of intelligence, a hair’s breadth away from monkeys.” It seems that God would more likely call into being a plethora of sentient life, and life much more impressive than humans in terms of intelligence, moral knowledge and character, religious knowledge, etc.
Whereas the arrival of humans imbued with tribal tendencies, cognitive errors, and libido after billions of years makes sense under evolution unaided by God. This isn’t to say that a more specific version of theism can’t explain why there are humans in particular but I know of no religion that can do so parsimoniously. Consider the kind of theory a Christian or Muslim might offer: Our cognitive errors are a result of Fall from a primordial garden. Our tribal tendencies derive from the scattering of languages that ensued from the destruction of the Tower of Babel (the Qur’an alludes to a similar event in Egypt). Our libido is because God wants us to have children, and (mysteriously) sex is the means He ordained for procreation. A great deal of ad hoc-ery is afoot.
But how can the atheist address the original worry about the monstrous improbability of sentient life on the assumption of naturalism? One not so great approach is to note that astonishingly rare events happen all the time (e.g. a person existing with your particular memories, genome, and epigenetic configuration). But that only reiterates the fact that naturalism can give rise to sentient life. It doesn’t answer the question, “Why this particular rare event?”
A better tactic is the so-called Anthropocentric Hypothesis, which posits the existence of a multiverse, a Universe of many universes, with “terrain” rich enough to explain why our universe has the particular physical constants it has. One possibility would be a multiverse that harbors universes with every possible combination of physical constants. In this case, the arrival of sentient life is almost guaranteed. The only reason we think it’s unlikely is that we can only examine the universe we inhabit, which must support life or we would not be around to inhabit it.
Now this multiverse is hokey and strange and probably not a scientific hypothesis in that there doesn’t appear to be empirical means by which we could falsify it. But is it hokey-er than God? Quite possibly not. God introduces immense complexity into a worldview, far more complexity than the four fundamental forces posited by physics. Simple theories have a wide attack surface, meaning there is a lot of conceivable evidence that could disconfirm them. But God is a hypothesis that can explain any event at all; no event is so strange that God could not have caused it. But there are innumerable aberrations that don’t happen, and if they did, our physics would be disconfirmed.
So when asked to consider whether a multiverse or God is more likely, the committed atheist will choose the multiverse, even though a multiverse is either unlikely or of indeterminate probability. Indeed, I think atheists such as myself have such pitifully low prior probabilities for God that all this talk about how likely theism is or naturalism is given sentient life, moral knowledge, consciousness, free will, worldly evil, etc. isn’t going to convince those a theist wishes to convince. Sometimes we feel the force of a probabilistic argument for God. They can nudge us around, but they aren’t going to change our minds.
What the theist has to do is show the atheist there is some part of his worldview he really wants to preserve but he can’t have on the assumption of naturalism. And then the embroiled atheist must make a choice. This is what I will do when I next discuss the Argument from Moral Knowledge.