Edward Feser has responded to my critique of the press release about his new book that I used as the basis for pouring cold water on the idea of trying to prove the existence of gods by arguments alone. Not surprisingly, he does not like what I said and says that if I had only read his book, I would see that my criticisms were either invalid or had been addressed by him. Probably as a result of Feser’s post, a couple of new commenters have come here to defend Feser (see comment #23 and later) and some of them have also taken me to task for not having read his book
I want to particularly thank Ye Olde Statistician @#25 and George @#26 for their responses to my post where they take issue with what I say. I am responding in a new post here because old posts tend to not be read after a few days, and also because my response is a bit lengthy.
It is true that I have not read the book and, to be quite frank, I have no plans to do so. If Feser and his supporters feel that that disqualifies me from commenting on the claims contained in his press release, so be it. Some time ago, I came to the conclusion that I was not going to learn anything new or useful from religious apologetics. If someone actually does come up with a killer proof that really does establish with certainty the existence of their god (as Feser claims to do in his press release), that will surely be big news (certainly bigger than a cure for cancer or even the arrival of a new iPhone) and I am sure that it will be all over the internet, make the newspapers, and will receive massive coverage on TV, the way that major scientific discoveries do. Then I will read it.
But for the moment, let’s back up a bit to refresh what this is all about. The title of Feser’s book is FIVE PROOFS OF THE EXISTENCE OF GOD and the accompanying press release says that “the existence of God can be established with certainty by way of purely rational arguments.” (Boldface emphasis mine)
These are very strong claims and are what I took issue with.
I agree with commenter George that “An argument consists of a conclusion attempted to be justified with premises through an inferential process” but I am afraid that I cannot agree with him that such an argument can count as evidence because that way lies circularity. Evidence is what one provides in support of an argument. If, as George says, Feser is appealing to features of everyday life as evidence, then Feser can no longer claim that the existence of his god can be established by means of purely rational arguments (his words) but is appealing to empirical evidence. Then the question shifts to the quality and persuasiveness of that evidence, how one deals with contradictory evidence, and whether there are credible alternative theories to explain that evidence that do not invoke the existence of any god. We thus quickly move away from ‘purely rational’ arguments and become enmeshed with evaluations of data and competing theories about the data. That is what science is all about.
It is also well known that given any set of data, however large, there are an infinite number of theories that can ‘explain’ that data and we thus have to find ways of making judgments about them by weighing what evidence is relevant and how much weightage each gets. The whole idea of proving empirical statements (such as the existence of entities) by arguments alone is not something that would be accepted in science. The existence of entities is established by a preponderance of evidence in support of the existence claim, and that necessarily includes data.
George suggests that we can arrive at true statements about the world in other ways using just premises and arguments, saying that in order to do so, “The premises must be justified as true and the argument valid for the conclusion to be true”. Therein lies the problem. It has long been known (starting with the work of Kurt Godel) that it is impossible for any non-trivial system to establish the validity of both those necessary conditions, and hence the goal of arriving at a system that is both complete and consistent and thus can establish unequivocally true statements is unattainable. The claim of certainty becomes infeasible. If that is the case in the more rigorous world of mathematics, what chance is there for such a program succeeding when we are dealing with claims about the empirical world?
Carl Sagan said that ‘extraordinary claims require extraordinary evidence’, a sentiment that predates him but his phrasing captures the idea succinctly. I am not sure what he and his predecessors would make of an extraordinary claim (and surely a claim of proof of the certainty of the existence of any god has to be considered truly extraordinary) that supporters claim did not require any evidence at all but could be established purely by rational arguments, perhaps supplemented by appeals to some everyday phenomena?