Contemporary cosmology has revealed that the emergence of intelligent life depends on a remarkably precise calibration of the universe’s physical constants and initial conditions. This phenomenon, known as fine-tuning, suggests that the parameters for a life-permitting universe occupy a vanishingly small slice of the total space of possibilities. As physicist Luke A. Barnes summarizes, “The claim is that in the space of possible physical laws, parameters and initial conditions, the set that permits the evolution of intelligent life is very small” (Barnes, Luke A. “The Fine-Tuning of the Universe for Intelligent Life.” Publications of the Astronomical Society of Australia, 29(4), 529-564, 2012). For example, if the universe’s early expansion rate had been infinitesimally different, it would have either collapsed back on itself or expanded too rapidly for galaxies to form.

In Where the Conflict Really Lies, Alvin Plantinga analyzes this data as evidence for a Fine-Tuning Argument (FTA) for theism. He argues that fine-tuning is highly probable in the context of theism but exceedingly improbable by chance. Plantinga systematically addresses major objections, including the anthropic principle (we can only observe a universe fine-tuned for us) and the multiverse hypothesis (our universe is just one of many, with one inevitably being life-permitting). He counters that even with many universes, the probability of this specific universe being fine-tuned remains low from an atheistic perspective that excludes the possibility of a divine, intelligent Creator. After weighing the arguments and counterarguments, Plantinga offers a measured conclusion, finding the FTA persuasive but not definitive proof: “The right conclusion, I think, is that the FTA offers some slight support for theism,” he writes. “It does offer support, but only mild support” (224).