When presenting the fine tuning argument, skeptics may respond that we are unduly privileging life as something special in the universe. For example, someone might object that the universe is also fine tuned to produce iPads. Why is the existence of life significant in a way that entails God, but iPads are not? The restriction to life is ad hoc. So here I will give an attempt to respond to this claim, and give some reasons why theism predicts life.
The claim of theism here is that there exists a deity, and by this we mean that there exists an all powerful, all knowing, always good creator of the universe. Or something along those lines. Importantly, we think that God is in some sense the goodest thing possible, perhaps even Goodness Itself. And we also think that God is intelligent. Perhaps God’s intelligence is somewhat different to our intelligence, since God is timeless and unchanging and simple. But still rightly called intelligence.
Since God is good, we can say that in creation, He is pursuing something good. In fact if we believe Leibniz (and I do, this fits well with Calvinism) then we can say that the world God creates is actually the best possible world. The best possible world must include some good things.
I claim now that intelligent beings are some of the goodest things. Since God is Goodness Itself and is intelligent, the least we can say is that intelligence is very good. We can indeed go further and say that intelligence is fundamentally linked to goodness, as all of God’s attributes are. And further still, we can argue that in creating the best possible world, God would create beings in His image. He is Good, so His image bearers must be at least very good.
Given this, we have some pretty good reasons to think that God would design a world that could support not just life, but intelligent life. Many atheists, especially Kantians, think there is something special about humanity, namely: reason. Our ability to reason is unique, and morally significant. Kantians think that reason is the basis for morality. So it seems like the Kantians would agree that if there is a God, then God would create beings with reason. Intelligent beings.
Since we can demonstrate that if theism is true, then the universe will support intelligent life, we can indeed rightly use a fine tuning argument. This is not ad hoc, we have not arbitrarily selected intelligence to examine, we have shown how intelligence is significant for God.