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
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.”
My Reply
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 necessary 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!
Another Argument
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”.
Conclusion
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.
Philosophy of Religion blog 
PSR is unarguably true independent of gods or anything else. All it needs is the logic of to whom or what the explanation for existence is appropriate. Everything that exists has such argument, applied to something.
Reblogged this on James' Ramblings and commented:
Reblogging for future reference.
What do you think of this post? It’s by an Atheist who endorses the PSR and put’s a logical argument forward that supports it.
I don’t see any obvious logical contradiction in denying the PSR, but I do see a practical one.
The PSR asserts that everything has an explanation. To deny it, one must assert that at least one thing exists but has no explanation. In order to know that such a thing exists, one must be able to explain what it is and explain why it has no explanation, which amounts to explaining it. So one can’t deny the PSR without confirming it.
That implies something to which you allude in your final section, where you say that “Feser is confusing method with belief.” I see the PSR as a Thomas Reid-ian assumption that we must make in order to do any thinking at all. It’s foolish to deny such assumptions, but it’s just as misguided to draw grand metaphysical conclusions from them; and the existence of God is as grand a metaphysical conclusion as one can reach.
Firstly, you will need to articulate what exactly an ‘explanation’ is. There is no consensus as to what it is to explain something. Since you do not give us the courtesy of expounding on what exactly an explanation is in your opinion, I will have to take the liberty of propounding my own preferred theory of explanation in order to illustrate why it does not seem that your argument is sound. For illustrative purposes, let’s simply presume a Lewisian of explanation, i.e “to explain an event is to provide some information about its causal history.” Now, let’s assume the truth of naturalism. On this assumption, the only causal entities that exist are natural entities and the only type of causation that exists is natural causation. On this hypothesis, there is no explanation as to why the causal reality exists. The existence of causal reality cannot have a causal explanation. Because the theory of explanation propounded explicates the notion of explanation in terms of causation, it follows there can be no explanation simpliciter. Now does this amount to an explanation as to why causal reality exists? Well, ask yourself, does it provide any information about the causal history of causal reality? If not, then no, we have not explained causal reality by acknowledging that it lacks an explanation.
The reason to accept the PSR is if not accepting it leads to absurdity or incoherence (contradiction). I would say that not accepting the PSR doesn’t necessarily create contradictions- as you said, you can think most things have explanations, but not everything- but I do think it leads to absurdity.
For this, we need to take a chain going up to the sky as an example. If there is a ceiling, the chain will hang up from the sky; but, if there is no ceiling, then no matter how long the chain, there is no reason for the chain to be hung from the sky in the first place. Similarly, if there is no explanation whatsoever for the fundamental level of reality (the chain as a whole in the example), there cannot really be an explanation for any of the lower levels either (the individual links of the chain).
Nor is it sufficient to respond by saying that the lower levels can have explanations even if the overall picture does not, for those explanations will fundamentally be insufficient- everything, truly, becomes a brute fact, at least in the existential sense. An example I’ll use will actually be a defense I’ve seen against the PSR. This defense says that, in order to fully understand something like economics, you don’t need to know a shred of quantum mechanics. Yet, this objection is undermined by the fact that, in order to know why economics EXISTS at all, you have to grasp quantum mechanics. For without quantum mechanics existing, economics simply won’t exist either. So, if quantum mechanics is a brute fact, and thus we don’t need to posit the existence of God, then economics becomes a brute fact as well even if we have some illusory explanations for it… Our explanations will never be complete. Hence, without the PSR, there no complete truth about reality, which staunchly brings into question the purpose and value of our philosophizing.
Personally, I think PSR is about as true a principle as you are ever going to find in philosophy. The OPs comparisons to black cats and the like misses the point: cats are distinct animals that are not connected in a hierarchical causal chain. One can be black, another can be orange, and they don’t affect each other.
Admitting brute facts is rather different. It is like saying that a coffee cup is supported by a table, which is supported by the floor, which is supported by the foundation of the house etc. and then when you get to fundamental laws of nature, you declare “well, it’s just a brute fact” and called it a day. If you haven’t explained where the power to be upheld ultimate comes from, you haven’t really explained anything else in the chain.