The Principle of Sufficient Reason (or PSR) states that everything that exists has an explanation for its existence. As Sean Carroll points out, “The PSR is kind of like that bumper sticker that says ‘Everything Happens For A Reason’ “.
Defending the truth of the PSR has not been easy for those that endorse it. Trying to defend it empirically leaves obvious problems on the table. Trying to justify it a priori hasn’t been easy either. For one, there doesn’t seem to be any contradiction in denying the PSR. Thus, the defender of PSR would have to show there is a contradiction. Secondly, appealing to intuitions shouldn’t be very convincing (if that’s the route one takes).
Recently, however, I have heard a sort of new argument for the PSR. I first read about it in Ed Feser’s recent book on God’s existence, but I then just heard it on a podcast this past weekend; therefore, I feel there is a need to address this argument because it seems to be becoming more mainstream. So, what is the argument?
The argument, which originates with Della Rocca, claims that there is some sort of inconsistency on the part of someone who denies the PSR. If someone allows some brute facts, the floodgates are supposedly opened. And, how can someone claim something is a brute fact without doing so arbitrarily? Feser says, “So, Della Rocca’s argument is that there seems no cogent way to accept EAs at all without accepting PSR. The implication seems to be that we can have no good reason to think anything is explicable unless we also admit that everything is.”
Seriously? That’s basically admitting that your argument leads to absurdity. It’s a total non-sequitur. Just because some things don’t have an explanation, that doesn’t mean that all things wouldn’t have an explanation. By Feser’s logic, we have no good reason to think any cats are black unless we admit that all cats are black! It’s nonsense from start to finish, and it shows you that Feser needs to get out more and spend less time in his head.
Secondly, one doesn’t have to say the PSR is false; rather, one can be skeptical that it is true! The burden of proof is on the proponent of the PSR to demonstrate that it is true. Pointing out that some people might be inconsistent in claiming that the PSR is false, does not by itself show that the PSR is true (that would be another non-sequitur). Even if we grant that some people are actually being inconsistent in rejecting (i.e. denying) the PSR, we still can’t get from there to the truth of the PSR. Once again, being skeptical of X is not the same thing as believing X is false.
Thirdly, I can’t help but think that Rocca and Feser are committing the line-drawing fallacy. They are claiming that if the defender of brute facts can’t come up with some neat line then checkmate. The problem is that it’s far from plain why there needs to be a line in the first place. Knowing when something is a brute fact could just be a case of ‘you know it when you see it’. It’s not evident that you have to have some sort of line.
Fourthly, at least when it comes to the cosmos as a whole, there is a reason to be skeptical about whether the PSR applies. It’s not as if we think everything in our everyday experience applies to the deepest levels of reality. That’s the difference between dogmatism and skepticism; skeptics are fine with saying “I have no idea”, whereas dogmatists aren’t. A common reply to this that I’ve seen is to say something like, “Of course we don’t have to know something with certainty”. This reply is a strawman; skeptics aren’t talking about certainty. When skeptics say things like, “I don’t know”, what they really mean is that they can’t say one way or the other. If I say I don’t know whether the number of stars in the universe is odd, I am not saying that I don’t know this with certainty. What I am saying is that I am totally in the dark about whether the number of stars in the universe is odd.
Fifthly, Feser actually gives atheists a way to escape the argument when he says, “Why, it’s almost as if such philosophers don’t want the PSR to be true, and thus would rather not have their prejudice against it disturbed. Can’t imagine why that might be, can you?” At best, accepting the PSR would lead one to believe in a neccessary entity. It does not uncontroversially lead one to a Being that is all-powerful and all-good, which Feser says it does. If it does, this gives the atheist an indirect way to respond to Feser:
1. If God does not exist, then the PSR is false (Feser’s claim)
2. God does not exist (see problem of evil, problem of divine hiddenness, etc).
3. Therefore, the PSR is false
I want to give credit here to non-theist philosopher, Graham Oppy. This is essentially Oppy’s way of responding to the PSR, assuming that it’s true that the PSR leads to theism. Nevertheless, it isn’t clear that the PSR leads to theism. And it certainly isn’t clear that atheists reject the PSR because they don’t want to be theists. For one, some atheists do accept the PSR. And second, some theists don’t accept the PSR! Thirdly, that’s just a red-herring/ad hominem from Feser. So, honestly, who is Feser trying to fool? Here he is coming off as a sophist instead of a philosopher. One can rationally think something is wrong with an argument even if they can’t quite put their finger on what exactly is wrong with the argument. In fact, that’s a large part of the history of philosophy. For example, something seems wrong with Anselm’s ontological argument to the average person. Should they just go and accept it as a sound argument because they can’t refute it? Of course not!
Feser has another argument which he borrows from Alexander Pruss. The argument is that if the PSR is false, then-for all we know- are senses might not be reliable. Yeah, I guess that’s logically possible, so perhaps Feser means to say more. Maybe Feser is saying that we can’t rule out the proposal that our senses are not reliable, if we reject the PSR.
For one, our senses are unreliable sometimes, and that is (ironically) evidence against God. Secondly, the main reason we trust that our senses are reliable is for investigation to even get started in the first place; therefore, the main reason we trust that our senses are reliable is a pragmatic reason. Thirdly, if one wants to be skeptic about sense perception, they are free to do so. After all, our senses do get things wrong quite a lot!
I think what’s going on here-and what also happened in the first argument- is that Feser is confusing method with belief. We behave and perform experiments like there is some explanation, but that does not entail that there really always is an explanation. We can act as if there really are explanations, but we do so for the sake of science, etc. And even if we really do believe that there are always explanations for things in our everyday experience, that doesn’t mean we really believe that literally everything has an explanation. And, as I’ve said before, I don’t see any inconsistency in believing that just almost everything has an explanation. But how can we differentiate? Off the top of my head, I’m not certain. But, by way of example, almost every human isn’t a total psychopath, but that doesn’t mean we can’t identify psychopaths or know them when we see them. Perhaps brute facts come into play when it makes no sense to ask for a further explanation of something. Even most theists grant that some propositions end up being brute facts, so why is it so damn absurd to think that some events or things can be brute facts as well? And, again, saying “I’m skeptical about whether the PSR is true” is not the same thing as saying, “The PSR is false”.
What we have seen here is another failure to justify the PSR. If there were really good grounds to accept the PSR, then we wouldn’t have some philosophers trying to conjure up new arguments. Heck, even before looking at these new arguments-from an inductive point of view-I knew that they were probably unsound. That’s because all of the justifications given for the PSR in the past have been little more than throwing shit on the wall and trying to see what sticks.