The Rights and Wrongs of Reppert on Defeasibility

Victor Reppert has criticized Peter Bogghosian’s use of the defeasibility test (where you ask someone what it would take to change their mind. If they can’t come up with anything, they’re being irrational).


He gives four criticisms. I make an effort to be charitable in my interpretation of people I disagree with (it helps that I used to be a believer) and I feel pretty sure that not all of his points are entirely wrong.


1 – Reppert says that an atheist should be willing to argue with a theist even if the theist says in advance that disproving all of their arguments wouldn’t change their mind, anyway. Most importantly, I want to note, to emphasize, that Reppert’s point here has no bearing on whether or not the defeasibility test is correct, that is, that it really does reveal irrationality. His criticism is about whether it’s useful to debate people; it has nothing to do with assessing if theists are being irrational or not.


And then, I want to agree with Reppert. It may indeed be useful to argue with someone who says having all their arguments refuted won’t change their mind.

(Of course, we’re only pretending that the “arguments” are really the believers reason for believing. I call this “pretending to argue,” and it dominates most of political and religious debate, since most people intend to maintain their stance even if you refute their point)


After all, it may be useful for you to practice perceiving the flaws in a twisted argument, or you might help any observers make up their mind about an issue. Reppert’s right in that. That’s Reppert Right: 1 – Wrong: 0.


2 – Reppert suggests that spiritual experiences are outside the realm of debate. He implies that you could refute a believer’s arguments, the believer would believe anyway, and then the believer would still be rational. This point does actually suggest that the defeasibility test is mistaken.



But, personally, I think spiritual experiences are fair game for a debate. There’s a meme that says “Atheists are so dumb that if Jesus appeared to them, they still wouldn’t believe, thinking it might be an alien.”

If I were to make an atheist version, I might say “Theists err such that if an alien were to appear to them looking like a glowing human and claiming to be Jesus, that would be enough to convince them.”


What possible spiritual experience could actually justify believing that you are definitely being talked to to by a perfect being who created the universe? We can even suppose that it is something supernatural. All we know is that it can look like a glowing human (or whatever it looks/feels like) and can make you feel certain things, and, at best, has access to some knowledge that humanity doesn’t have. That leaves open a lot of possible causes. I invite anyone who can to submit a spiritual experience which could only be explained by a perfect universe-creator, which cannot also be explained by a million other possibilities. You can even make something up, as incredible as you like.

(Reppert Right: 1 – Wrong – 1)


3 – Reppert’s third point is that there might be something that would convince a theist that they were mistaken, but that they might not be able to think of it right on the spot, so we shouldn’t conclude they are necessarily irrational.


Ah. Marvelous. If I’m not mistaken, Reppert and I agree that if there is nothing that would change a theist’s mind, they would be irrational. Another point to him.


Of course, he’s right. You’ve thought of snappy comeback too late to be snappy, right? It’s conceivable that someone could think of evidence that would convince them just a little too late to be able to tell it to you. Very reasonable (of course, it’s still suggestive that they are irrational. It’s evidence. Observing them not be able to think of anything at least makes it more likely that they are irrational).

(Reppert Right: 2 – Wrong: 1)


4 – Reppert says some atheists also cannot think of anything that would change their mind. Are they irrational, too?


Of course, atheism is not a sports team or a political party. There’s no reason to deny that some atheists are irrational people, and their existence is no argument against the defeasibility test. This is more what I call a Halo Attack.


The Halo Effect is where something seems better in every way, just because it’s good in some way, ie, pretty people are perceived as smarter, more honest, kinder, etcetera.


Most arguments are just Halo Attacks in that, rather than arguing that something is false, you argue that it fails in some other way, instinctively feeling that if it is weak in any way, it must be weak in every way, including whether it’s true or not.


Yeah…they are many, the flaws in the human brain.


So, getting in a solid, satisfying hit on “enemy group Atheists” may feel like scoring points to the human brain, but more careful reasoning reveals that to be an irrational method of determining if something is true or not.


At the same time, I feel like there is a difference between looking at a vast space of possible explanations for things, and then saying you think the right one is one little point in that great space, and you cannot be persuaded otherwise (theists), and being someone who looks at that space and says “Here and there, there are a few points that I could not be persuaded are true. I don’t know the answer for sure, but I’m sure it is in that vast space somewhere, excluding a few possibilities” (atheists).


Personally, I could be persuaded to think it more likely that there was indeed a creator, or a very powerful being, or that faith healing worked, or any number of things, but I can’t think of anything that would persuade me of the full set of ideas in any mainstream religion.


You see, if I were somehow convinced that an all-powerful being existed, my ability to assess that being’s honesty would drop to 0. No matter what its other qualities were, it could effortlessly appear to be absolutely anything it wanted, with perfectly persuasive evidence on any possible scale. Upon seeing such evidence, I would greatly increase my probability that the being was very powerful, also increase the probability of it being all-powerful (not sure I could tell the difference, though), but remain totally agnostic as to whether or not it was an honest being.


And if it told me it created the universe, and was going to give me an afterlife, I would raise my probability of that being true somewhat, but not even nearly to total certainty, since it could just be lying, and it would be the greatest liar possible if it wanted to be.

(Reppert Right: 2 – Wrong: 2)


I may have misunderstood Reppert in some minor respects; I recognize that possibility. But the points I feel quite sure about (and invite criticism of) are:


1 – No possible spiritual experience can only be explained by any mainstream religion’s concept of God, and so, cannot be decisive evidence for that God.

2 – No possible evidence of any kind could only be explained by any mainstream religion’s concept of God, and so, cannot be decisive evidence for that God.


Best of luck. If you reveal to me some error in this reasoning, I will consider it a great gift.


































Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s