(1) If the God of classical theism existed, with the purposes traditionally ascribed to him, then he would create a universe on a human scale, i.e. one that is not unimaginably large, unimaginably old, and in which human beings form an unimaginably tiny part of it, temporally and spatially.Everitt does not claim that the scale of the universe proves God does not exist. Rather, he concludes, "the claim is only that the findings of modern science significantly reduce the probability that theism is true." See Nicholas Everitt, The Non-Existence of God (New York: Routledge, 2004), pp. 213-226.
(2) The world does not display a human scale.
(3) Therefore, there is evidence against the hypothesis that the God of classical theism exists with the purposes traditionally ascribed to him.
What should we make of this argument? Premise (2) is uncontroversial. Premise (1), however, is likely to be controversial. What defense does Everitt offer on behalf of (1)? According to Everitt, "For reasons that are not entirely clear, God decides to create a universe in which human beings will be the jewel." Because humans are the jewel of the universe, the rest of the universe will be at least not unremittingly hostile or even indifferent to human flourishing. Indeed, given theism, you would expect the universe will make such flourishing at least accessible in principal to human beings.
Furthermore, Everitt argues, given theism, we have some reason to expect a scenario like Genesis. Traditional theism would lead us to expect human beings to appear fairly soon after the start of the universe. Given theism, you would not expect humans to arrive very long after after the animals; you would expect the earth to be in a significant location within the universe (perhaps the center); you would expect the total size of the universe to be not many orders of magnitude greater than the size of the earth; and you would expect the greater part of the universe to be accessible to human exploration.
When I spoke with philosopher Paul Draper about this argument many years ago, he said that he believes the scale of the universe is only slightly more probable on metaphysical naturalism than on theism; the argument does not significantly raise the ratio of the probability of naturalism to the probability of theism. As Draper points out, if you think, given theism, God's goal is to create humans, you'd have an antecedent reason for expecting the universe to be on a human scale. But it is far from obvious, given theism, that the goal is humans. An omnipotent being is not short on space or time. Maybe God created multiple universes. If there's only one universe and if God is in time, then it would be a little bit of evidence favoring naturalism.
I'm inclined to agree with Draper. It seems to me that the evidence of the "scale of the universe" is, at best, weak inductive evidence against theism.