Michael Barkasi

philosopher and cognitive scientist

Overconfident blowhards and Pyrrhonian sheepishness: Two varieties of credence-dynamic epistemic viciousness

Just this morning a post in a Facebook group for professional philosophers specializing in epistemology (Board Certified Epistemologists) got me thinking about the following type of case. I should note, before starting, that while I am a professional philosopher, epistemology is not my speciality. So, I’ll be musing about some stuff outside my wheelhouse. Still, the topic is interesting and I find it personally relevant (as will be clear in a moment). A final caveat: while I’m pretty sure I came up with these ideas on the spot while reading the Facebook post, I’m also sure they aren’t original. Someone researching credences or epistemic vices has presumably said this stuff before.

Consider all the possible claims one might make, from the mundane (“it’s raining here and now”) to the profound (“God exists”), whether about science (“the world is made of atoms”) or art (“Slash is better than Hendrix”). Some of these claims we believe, while others we don’t. For most people, belief isn’t all or nothing. Instead, we assign a certain credence to the claim. The scale is arbitrary, but usually professional epistemologists range credences between 0 and 1. For example, if I assign credence 1/2 to some claim, I’m completely indecisive between whether it’s true or not. If I assign a credence of 1, I completely believe the claim as strongly as possible. If I assign 0, I believe the claim is false with no doubt or hesitation. This is perhaps not the most technically correct or conceptually clean way to way to explain credences (apologies to the real board certified epistemologists), but you get the idea.

Now this post raised the issue of what to call people who are disposed to only ever hold credences very close to 0 or 1. The natural name for them is “opinionated”, but some worried this was a bad name, since it implies the person is dogmatic or (to put it less kindly) an overconfident blowhard. After all, couldn’t some people who tend to hold credences only ever clustering close to 0 or 1 be more “elastic” than others? Say two such people both hold credence .999 in some claim. One of them might be more amenable to new evidence than the other, more apt to change their mind. This person is definitely not an overconfident blowhard.

I want to press back against this idea. If your cognitive architecture, your psychological makeup, really does dispose you to only ever hold credences very close to 0 or 1, than (I think) you probably would be an overconfident blowhard. Say, for example, you take credence .999 in some claim. Someone presents you with evidence that this claim is false. If you were apt to take a more reasonable range of credences towards claims, this new evidence would cause you to lower your credence to something a little lower, say, .7. After all, you might have good reason to believe the claim, but faced with compelling new evidence, the rational thing to do is be a little less confident in the claim.

But now consider how our subject who clusters their credences around 0 and 1 could respond. This person isn’t apt to assign a credence of .7 to any claim. Their psychological makeup disposes them to only take extreme credences. So, faced with new evidence, they only have two choices: (a) completely reject the new evidence and double down on their original credence of .999, or (b) accept the new evidence and completely flip to an ultra low credence of something like .001. It seems unlikely that someone who puts such extremely high credence in a claim would, when faced with evidence that would make a rational person lower their credence to (say) .7, accept the evidence and flip to an ultra low credence. (And, in any case, such an extreme flip would be irrational.) So, they are going to keep that ultra high credence. We, of course, have a (not so nice) term for those who keep ultra high credences even in the face of evidence that calls for adjustment: overconfident blowhards. (Note that all this still holds even if our subject does adjust his credence a little, say from .999 down to .997; all the same, the person is still an overconfident blowhard.)

Thus, even if it’s true that the English term “opinionated” implies one is an overconfident blowhard, it’s still a good name for the person who is disposed to cluster their credences around 0 and 1. Henceforth, I’ll call this person an “opinionated believer”.

What I find interesting though isn’t the opinionated believer, but another pattern of assigning credences: the person who is disposed to only assign credences close to 1/2. This is the indecisive person. Not necessarily indecisive in taking actions, but indecisive in deciding whether they think a given claim is true. I find this type of person more interesting because I am this type of person. At least for me, I find it hard to take credences far off 1/2 because I usually find myself appreciating opposing arguments. For almost any claim you will find people on each side presenting good evidence both for and against it. (Of course, you’ll also find many, many people presenting terrible arguments for and and against it.) When faced with this sort of pull from both argumentative directions, I simply find it hard to decide whether or not to believe the claim, so I settle into an indecisive credence like 1/2, or perhaps something just over or under 1/2. Since this is the situation made famous in Pyrrhonian Skepticism, I’ll call this person (including myself) a “Pyrrhonian believer”.

It’s obviously bad to be an opinionated believer, because (as we just discussed), such people are overconfident blowhards. But it’s also bad to be a Pyrrhonian believer. Pyrrhonian belief formation also involves an epistemically vicious dynamic for forming credences, albeit one that’s a little more subtle than that involve in opinionated believers.

Say I hold my normal credence of 1/2 towards some claim, and someone presents me with reasonable (new) evidence for the claim’s truth. The rational response is to up my credence a little, say to .7. But as I consider the new evidence, my Pyrrhonian tendencies incline me to also reconsider all the arguments against the claim. I am (again because of my Pyrrhonian tendencies) swayed by both the new evidence and my reconsideration of the old evidence, and so instead of settling on a rational credence of .7, I fall back to my original credence of 1/2, or perhaps to something marginally higher, like .501. But it gets worse. Consider now a situation in which I finally get off that 1/2 credence and move it substantially higher. What would that take? Well, it would take very strong evidence that overwhelms my Pyrrhonian tendency to reconsider all the original evidence against the claim, or at least it would take evidence that I believed overwhelmed all the original evidence. Hence, in that situation, I would naturally shoot my credence all the way up to 1, or very close to it. After all, if I saw any reason not to hold a credence of 1, my Pyrrhonian tendencies would grab onto that reason and drag my credence back down to 1/2.

So the Pyrrhonian believer is normally paralyzed with indecision about whether to believe a given claim, and when they do occasionally resolve that indecision, they resolve it via wild spikes up to full credence (1) or down to full disbelief (0). I think this theory about Pyrrhonian belief dynamics is plausible, both because of the argument I just gave, and because I observe these dynamics within my own belief formation and credence assignment. (And, since I am a Pyrrhonian believer, I’m already anticipating all sorts of objections and counter replies which will make me adjust my credence in this theory about Pyrrhonian belief dynamics down to 1/2! If I had talked to myself about this topic long enough before posting, I likely would have talked myself out of it, or just been too indecisive about its truth, and not posted at all.)

Both opinionated and Pyrrhonian belief formation tendencies are an example of epistemic vices. An epistemic vice is a character trait that hurts one’s ability to form rational beliefs (i.e., beliefs that confirm to the evidence and are apt to be true). The corresponding epistemic virtue is the tendency to form rangy, elastic credences: credences that cover the whole spectrum from 0 to 1, and which one quickly updates based on new evidence. While it’s best to be a rangy, elastic believer, I said I think the worst is to be an opinionated believer. It’s better to be a Pyrrhonian believer because withholding belief (assigning credences close to 1/2) at least saves one from being wrong. The Pyrrhonian won’t strongly accept lots of claims that are false, while rejecting lots of claims that are true. Further, the Pyrrhonian will be more cautious to act on their beliefs or the claims of others, unlike the opinionated believer, who never sees any reason not to act on their beliefs or the claims of others (and hence will often unwisely dive into situations that ought to have been avoided).

If there’s a practical upshot, it’s that one should be aware of these three types of credence-assigning tendencies. Everyone should work on being more of a rangy, elastic believer, while working to avoid being opinionated or Pyrrhonian. Knowing about these tendencies can help one see and avoid them.

Overconfident blowhards and Pyrrhonian sheepishness: Two varieties of credence-dynamic epistemic viciousness