In this section Keller provides no clue to the existence of a supernatural entity, but refutes a common critique of other clues. The clue killer is evolutionary biology. This section is fairly long but can be summed up concisely, as Keller did in closing.
It comes down to this: If, as the evolutionary scientists say, what our brains tells [sic] us about morality, love, and beauty is not real– if it is merely a set of chemical reactions designed to pass on our genetic code– then so is what their brains tell them about the world. Then why should they trust them?
Earlier, I wrote that Keller seemed to indicate that he understood what science was. This section argues strongly against that.
The simple answer to Keller’s question is that scientists don’t trust what their brains tell them. They do experiments as tests. As I said in the previous post, science was developed as a process to sort out things that are true from things we only think our true because of all the mistakes our brains make.
You could argue that experiments are not good enough. Scientists still have to see with their eyes and think with their brains, ultimately. Even if the experiments can be replicated by others and be used to make airplanes and cell phones, that doesn’t necessarily mean that what we experience is the true reality.
Philosophically this is correct. There is no way to know for certain that what we experience has any relation to reality. Science assumes that the universe exists, that I exist, and that I can observe the universe. From there it went on to double the human life span and stuff like that.
All the advancements and interwoven explanatory power of science might all be an illusion, it’s true, but that doesn’t get a believer in god anywhere. All it does is make any knowledge impossible, making any possible belief equally likely. It would be exactly as likely that a trillion trillion ant gods are dreaming our existence without knowing as they battle for the cosmic corn kernel as that the bible was accurate.
Nobody really thinks this way anyway. If they want to call into question the validity of science they have to reject one of the assumptions of science, and there are only those three listed above. I don’t think they can creditably do that, since rejecting any one makes living fairly impossible, and certainly makes having any sort of argument about the nature of the reality impossible.
This is not to say that science is perfect or that it can never be wrong. Any specific belief in science can, and should, be questioned whenever possible, but Keller is trying to question the entire methodology of science as a way of knowing things, and he has no basis for doing so.
Keller doesn’t like some of the current hypotheses of science and he has proposed alternative explanations as rivals. The alternative explanations are unconvincing, however, since they do not fit in with what is known with the rest of reality, and they are tinged with his obvious bias towards a belief in a Christian deity. He feels ever more threatened because the more we do experiments the more evidence we find against his position. Rather than adjust his beliefs, which would be the reasonable thing to do, he tries to come up with a catch all reason why science doesn’t matter. Unfortunately, the best one he can come up with invalidates all his arguments as well and makes life incoherent and debate meaningless. Still, he includes it in his book about reason. This is a clue to the strength of his position.