[ Author Bio ]
The key premise of the fine-tuning argument for the existence of God is the alleged improbability of the physical constants taking on values that fall within the narrow life-friendly range. In this paper Aron Lucas examines whether this improbability alone is enough to ground a successful theistic argument from design. He concludes that the fine-tuning proponent is impaled on the horns of a trilemma: he can either reject the argument for having a false premise, reject it for being circular, or accept it at the cost of rejecting the moral argument for the existence of God.
In Hume's Abject Failure, philosopher John Earman argues that David Hume's famous maxim that no testimony is sufficient to establish that a miracle has occurred unless its falsehood would be more miraculous than the miracle itself is just a trivial tautology, namely that we should not believe a miracle claim unless the evidence makes it more probable than not. But even if this interpretation is correct, contemporary Christian apologists fail to satisfy Hume's purportedly obvious condition that it must be more probable that a miracle occurred than that it did not occur when they argue that the miraculous resurrection of Jesus probably occurred.
If the values of the physical constants of our universe were even slightly different, life could not exist. Some have argued that the fact that life does exist thus provides strong evidence that God fine-tuned these values to allow life to emerge. According to the fine-tuning argument, the existence of a life-permitting universe is very improbable on naturalism, but not so on theism. However, we have no way of determining the probability or improbability of actualizing a life-permitting universe on naturalism, for we can only compare our universe against the infinitesimally small subset of other possible universes that have the same physical laws—not the infinite set of all other possible universes.
The massive Blackwell Companion to Natural Theology aims to be the standard reference work supplying the best reasons to believe that God exists from the foremost experts on various arguments for the existence of God. It is not recommended for readers without some background knowledge of the philosophy of religion, modal logic, and Bayesian confirmation theory. Nevertheless, it cannot be ignored by anyone who wishes to argue that belief in God is irrational or intellectually bankrupt. In this review, Aron Lucas focuses on its chapters on the kalam cosmological argument, the fine-tuning argument, the moral argument, and the argument from miracles. Despite some valuable novel contributions, the volume focuses too heavily on defending some premises while ignoring others, and is highly technical even for advanced readers, with one argument presented in 87 steps purely using symbolic logic. One can only wonder why God would make the evidence for his existence accessible only to a select handful of professional academics, let alone punish people with eternal torment because they failed to properly apply Bayesian reasoning to little known historical data. The very fact that the volume needs to dig so deep in order to make its case is, in a way, evidence against the existence of God.