Walter Bradley asked me for some thoughts on fine tuning arguments. He is giving a talk on the subject at the ASA meeting in Golden this summer. Walter and I have had some very good debates on this topic before. I put together a few random thoughts on the topic and would like to share with you what I sent to Walter. Your comments would be greatly appreciated.
In a nutshell: The lack, no matter how fundamental, of a scientific causal explanation of a phenomenon, no matter how awesome or precise, is never evidence for the existence of God. Conversely, the faith-based presupposition that God the Creator exists renders the existence of the universe, whether understood scientifically or not, comprehensible.
The fine-tuning argument is the clearest example of the genre of arguments for the existence of God known as “God of the Gaps.” The gap is our utter lack of knowledge of how the cosmological constants came to have their unique values, which in many cases have an incredibly high precision. It seems possible that this gap may even be fundamental so that we may never be able to understand the source of these values. The premise that God is the agent who chose and assigned those values seems eminently plausible since God is omniscient and omnipotent and the Creator of all things. The selection of these values is in a sense the very essence of creation. But the gap of our knowledge is not in any way evidence for God’s existence or role in establishing those values.
I personally believe that God does exist and is the creator of all things and that he fixed these values. But I do not believe that the finely tuned values constitute any shred of evidence for the existence of God. Rather, the existence of God is a faith-based presupposition which makes the values of the constants comprehensible. The difference is profound.
At this time, no one has any idea of how these values came to be, how they might be related, or even whether they could possibly have any other value. Nor do we have any independent evidence that an intelligent agent exists or could in any way influence these values. The claim that God could do so is a logical possibility but one for which there is no evidence.
The claim that there is no other known cause of fine-tuning does not offer any support for the claim that therefore it must be God. It is far more likely that we simply do not know and may never know.
Stephen Meyer points out in his book Signature in the Cell (page 161) that philosopher of science Michael Scriven has discussed the method of reasoning called “retrospective causal analysis.” The central point is that “to establish the cause of a past event, historical scientists must first show that any candidate cause ‘has on other occasions clearly demonstrated its capacity to produce an effect of the sort here under study’” In this case, there is no independent indication that the cosmological constants can be established by anyone or anything, let alone by a God. The only rationale is a logical construct that a God should be able to accomplish it. This does not constitute evidence. (and no, no one is talking about ‘proof.’)
Finally, the apostle Paul is not referring in Romans to scientific methodology of which he has no knowledge. The passage in Romans 1 cannot rightly be used to argue that evidence for the existence of God can be deduced from scientific observations. Rather, he refers to the universal sense of awe that elicits the faith-based sense of God’s creative power and grace. A close literal reading of the text also seems to indicate that God’s existence is a presupposition and, given that God exists, what is clearly perceived from nature is his power and his divine nature, not specifically his existence. One cannot deduce from this verse that scientific observations like the cosmological constants clearly reveal God’s existence.
As for Duns Scotus, it was Mark Noll who traced a common fallacy back to John Duns Scotus and William of Ockam. This is the fallacy that there is only one essence of being such that only one causal explanation can be correct. Therefore, we have the fallacy that scientific explanations are mutually exclusive to theistic ones. Hence, if there is no scientific explanation, then the theistic explanation must be true. Conversely, if there is a scientific explanation, then the theistic explanation must be false. The fine-tuning argument falls into the former category with its claim that since there is no scientific explanation, the theistic source must be correct.
Note added on 9/23/2017 by RDI:
The talk that Walter Bradley gave at the ASA meeting on July 30, 2017 can be heard here and the slides at this link.
On a previous occasion, September 30, 2015, Walter and I debated this topic at a series of Roundtables. His presentation and mine at the Cambridge Roundtable are attached to this post.