By my lights, the following considerations are sufficient to show that the argument from fine-tuning fails to make theism more likely than not.

There is an equally good, rival explanation of the apparent fine-tuning of our universe. For the fine-tuning for life would be equally well explained if our universe were embedded in a vast “sea” of infinitely many other universes.[1] Imagine a natural process or mechanism that continually generates universes (call it a 'cosmos generator') – perhaps something like a giant quantum field. Each time it pumps out a universe, it gives a random combination of values to its fundamental constants of nature. So on this hypothesis, infinitely many other universes exist – or at least lots and lots – and each one has a different set of values for its fundamental constants. Most of these universes have no life, since only a few possible combinations of values of the constants are life-permitting. But some do (e.g., ours). If so, then the …

There is an equally good, rival explanation of the apparent fine-tuning of our universe. For the fine-tuning for life would be equally well explained if our universe were embedded in a vast “sea” of infinitely many other universes.[1] Imagine a natural process or mechanism that continually generates universes (call it a 'cosmos generator') – perhaps something like a giant quantum field. Each time it pumps out a universe, it gives a random combination of values to its fundamental constants of nature. So on this hypothesis, infinitely many other universes exist – or at least lots and lots – and each one has a different set of values for its fundamental constants. Most of these universes have no life, since only a few possible combinations of values of the constants are life-permitting. But some do (e.g., ours). If so, then the …