Friday, November 11, 2022

Credence-First Skepticism

Philosophers usually treat skepticism as a thesis about knowledge. The skeptic about X holds that people who claim to know X don't in fact know X. Religious skeptics think that people who say they know that God exists don't in fact know that. Skeptics about climate change hold that we don't know that the planet is warming. Radical philosophical skepticism asserts broad failures of knowledge. According to dream skepticism, we don't know we're not dreaming. According to external world skepticism, we lack knoweldge about the world beyond our own minds.

Treating skepticism as a thesis about knowledge makes the concept or phenomenon of knowledge crucially important to the evaluation of skeptical claims. The higher the bar for knowledge, the easier it is to justify skepticism. For example, if knowledge requires perfect certainty, then we can establish skepticism about a domain by establishing that perfect certainty is unwarranted in that domain. (Imagine here the person who objects to an atheist by extracting from the atheist the admission that they can't be certain that God doesn't exist and therefore they should admit that they don't really know.) Similarly, if knowledge requires knowing that you know, then we could establish skepticism about X by establishing that you can't know that you know about X. If knowledge requires being able to rule out all relevant alternatives, then we can establish skepticism by establishing that there are relevant alternatives that can't be ruled out. Conversely, if knowledge is cheaper and easier to attain -- if knowledge doesn't require, for example, perfect certainty, or knowledge that you know, or being able to rule out every single relevant alternative -- then skepticism is harder to defend.

But we don't have to conceptualize skepticism as a thesis about knowledge. We can separate the two concepts. Doing so has some advantages. The concept of knowledge is so vexed and contentious that it can become a distraction if our interests in skepticism are not driven by an interest in the concept of knowledge. You might be interested in religious skepticism, or climate change skepticism, or dream skepticism, or external world skepticism because you're interested in the question of whether god exists, whether the climate is changing, whether you might now be dreaming, or whether it's plausible that you could be radically mistaken about the external world. If your interest lies in those substantive questions, then conceptual debates about the nature of knowledge are beside the point. You don't want abstract disputes about the KK principle to crowd out discussion about what kinds of evidence we have or don't have for the existence of God, or climate change, or a stable external reality, and how relatively confident or unconfident we should be in our opinions about such matters.

To avoid distractions concerning knowledge, I recommend that we think about skepticism instead in terms of credence -- that is, degree of belief or confidence. We can contrast skeptics and believers. A believer in X is someone with a relatively high credence in X, while a skeptic is someone with a relatively low credence in X. A believer thinks X is relatively likely to be the case, while a skeptic regards X as relatively less likely. Believers in God find the existence of God likely. Skeptics find it less likely. Believers in the external world find the existence of an external world (with roughly the properties we ordinarily think it has) relatively likely while skeptics find it relatively less likely.

"Relatively" is an important word here. Given that most readers of this blog will be virtually certain that they are not currently dreaming, a reader who thinks it even 1% likely that they're dreaming has a relatively low credence -- 99% instead of 99.999999% or 100%. We can describe this as a moderately skeptical stance, though of course not as skeptical as the stance of someone who thinks it's 50/50.

[Dall-E image of a man flying in a dream]

Discussions of radical skepticism in epistemology tend to lose sight of what is really gripping about radically skeptical scenarios: the fact that, if the skeptic is right, there's a reasonable chance that you're in one. It's not unreasonable, the skeptic asserts, to attribute a non-trivial credence to the possibility that you are currently dreaming or currently living in a small or unstable computer simulation. Whoa! Such possibilities are potentially Earth-shaking if true, since many of the beliefs we ordinarily take for granted as obviously true (that Luxembourg exists, that I'm in my office looking at a computer screen) would be false.

To really assess such wild-seeming claims, we should address the nature and epistemology of dreaming and the nature and epistemology of computer simulations. Can dream experiences really be as sensorily rich and realistic as the experiences that I'm having right now? Or are dream experiences somehow different? If dream experiences can be as rich and realistic as what I'm now experiencing, then that seems to make it relatively more reasonable to assign a non-trivial credence to this being a dream. Is it realistic to think that future societies could create vastly many genuinely conscious AI entities who think that they live in worlds like this one? If so, then the simulation possibility starts to look relatively more plausible; if not, then it starts to look relatively less plausible.

In other words, to assess the likelihood of radically skeptical scenarios, like the dream or simulation scenario, we need to delve into the details of those scenarios. But that's not typically what epistemologists do when considering radical skepticism. More typically, they stipulate some far-fetched scenario with no plausibility, such as the brain-in-a-vat scenario, and then ask questions about the nature of knowledge. That's worth doing. But to put that at the heart of skeptical epistemology is to miss skepticism's pull.

A credence-first approach to skepticism makes skepticism behaviorally and emotionally relevant. Suppose I arrive at a small but non-trivial credence that I'm dreaming -- a 0.1% credence for example. Then I might try some things I wouldn't try if I had a 0% or 0.000000000001% credence I was dreaming. I might ask myself what I would do if this were a dream -- and if doing that thing were nearly cost-free, I might try it. For example, I might spread my arms to see if I can fly. I might see if I can turn this into a lucid dream by magically lifting a pen through telekinesis. I'd probably only try these things if I had nothing better to do at the moment and no one was around to think I'm a weirdo. And when those attempts fail, I might reduce my credence that this is a dream.

If I take seriously the possibility that this is a simulation, I can wonder about the creators. I become, so to speak, a conditional theist. Whoever is running the simulation is in some sense a god: They created the world and presumably can end it. They exist outside of time and space as I know them, and maybe they have "miraculous" powers to intervene in events around me. Perhaps I have no idea what I could do that might please or displease them, or whether they're even paying attention, but still, it's somewhat awe-inspiring to consider the possibility that my world, our world, is nested in some larger reality, launched by some creator for some purpose we don't understand. If I regard the simulation possibility as a live possibility with some non-trivial chance of being true, then the world might be quite a bit weirder than I would otherwise have thought, and very differently constituted. Skepticism gives me material uncertainty and opens up genuine doubt. The cosmos seems richer with possibility and more mysterious.

We lose all of this weirdness, awe, mystery, and material uncertainty if we focus on extremely implausible scenarios to which we assign zero or virtually zero credence, like the brain-in-a-vat scenario, and focus our argumentative attention only on whether or not it's appropriate to say that we "know" we're not in those admittedly extremely implausible scenarios.


Clayton Littlejohn said...

Hi Eric,

Great post. I agree that we should recognise forms of scepticism that aren't so knowledge-centred, but I'm not yet convinced that the credal approach captures some of the important things about the sceptical puzzle/challenge/fear etc. Suppose you are a theist and you think God might have a favourite number. Could it be 3? Absent any special information, my credence that it's 3 might be (this is a technical term) pretty small--about the same as it is for any number I can think of. I'm not convinced that it's not 3, not surprised/pleased/intrigued/disappointed that it's not 3. I'm still curious as to whether it is 3. That curiosity will never be satisfied (e.g., by bearing some attitudinal relation to the content that it's not 3) and it's not because my credence isn't yet high enough.

There are 100 prisoners exercising in the yard when 99 of them (two conditions here):

... attack the guard in some overly complicated way. One of the prisoners didn't participate. All we know about Agnes here is that she was in the yard at the time of the attack.

... sang 'Happy Birthday' to one of the inmates in the infirmary. One of the prisoners didn't join in. They faced possible punishment for this act of kindness. All we know about Agnes here is that she was in the yard when the song was sung.

My credence that Agnes attacked or sang (depending upon which case we want to consider) is close to 1, but given the information on hand, my curiosity isn't satisfied, it will remain unsatisfied until I get information that differs in kind, that information might satisfy that curiosity even if it lowers my credence, I won't be pleased that/upset that/surprised that/etc. until I get that different kind of information and it seems that there's a kind of connection to the truth that having a high degree of confidence won't give me. I take it that much of our interest in sceptical puzzles derives in large part from the fact that we're disturbed when we think that this kind of connection to the truth might be missing and that connection isn't a matter of high confidence and isn't a matter of high confidence + truth.

I think there are sceptical puzzles that focus on credences, but I don't think we get to the heart of many of the most interesting ones by thinking about whether it's a situation that warrants a high/middling/low degree of confidence.

Phil Tanny said...

It can be argued that philosophers can most usefully serve by inspecting unexamined assumptions at the heart of a group consensus. If fundamental assumptions on any matter are false, they can be an incurable source of problems until they are revealed to be false, at which point such assumptions can be constructively reconsidered.

If the above is true, then skepticism is obviously a very important matter for philosophers, as skepticism is the tool by which the philosopher questions that which most people assume to be true.

In our time, the most important group consensus assumption that philosophers should apply skepticism to is the belief that more knowledge is always better.

This belief is a ripe target for skeptical investigation by philosophers for at least five reasons:

1) This "more is better" belief is almost universally held.

2) This belief is a largely unexamined assumption typically taken to be an obvious given.

3) This belief forms the foundation of our science based modern civilization.

4) The future of this civilization will be determined by our relationship with knowledge.

5) This "more is better" relationship with knowledge assumption can not withstand skeptical scrutiny.

An additional reason that philosophers should apply skepticism to this assumption at the heart of the modern world is that we can't count on anyone else to do it. Many segments of society (scientists, corporations) have a built-in bias against challenging the status quo, while other segments (politicians, celebrities etc) are not qualified to apply the needed skeptical examination of such a fundamental issue.

The very first step of such an important investigation is likely for academic philosophers to apply skeptical scrutiny to their own unjustified belief that our relationship with knowledge is just one of a thousand topics meriting our attention.

Click my name for more.

SelfAwarePatterns said...

I'm totally onboard with the credence approach. It has a lot of advantages to a binary notion of whether we think something is true of false. For example, I can say that my credence in any culturally specific version of God is south of 1%, but that my credence for the more vague notions might rise to something like 10-20%. (Or even near 100% for the naturalistic pantheistic versions.)

Often people resist credence estimates like this because they think the percentage is somehow being unduly precise, a precision that feels like overreach. But to say I have 10% credence in something isn't to say my credence is between 9% and 11%. It's to say that while I don't think it's true, I could see it plausibly being true. Compare that to something which is 0.1%, which I'd be pretty shocked to discover was true.

Another reason to resist is because this approach largely clarifies what we mean when we say we're "agnostic" about something. Unless our credence is in the 40-60% range, saying we're agnostic feels like dodging the question. But often dodging the question is exactly what we want to do.

Excellent post Eric!

Steven B Kurtz said...

It is quite easy to put the ball in the court of the proposer/believer. I simply tell them that if evidence is presented to support the existence of anything not physical (energy-matter-information), or extricable from it, a Nobel Prize is likely along with around a million bucks. If they have no such supporting evidence, then their assertion is a simple speculation.

Phil Tanny said...

@Steven, sometimes it is equally easy to bounce the ball back in to the skeptic's court. When the skeptic requests evidence, the skeptic bears the burden of demonstrating that the rules of human reason are binding upon the subject at hand. If a skeptic insists that those rules are binding upon everything everywhere, and they can't provide proof of that claim, then...

They aren't really a skeptic, but a person of faith.

Dan Polowetzky said...

Would a similar approach be appropriate for the philosophy of language? If one’s interest is in the phenomena to which language is usually applied, i.e. non-linguistic objects (rocks and trees, dogs and cats, minds), then isn’t the heart of the philosophy of language examine the nature of those things rather obsessing over linguistic concepts as “reference”, “meaning”, etc.?
The examination of language and its possible distortions may be relevant to (say) consciousness, but the complexities of consciousness, subjectivity, qualia, and privacy, etc. (mostly) derive from the complexities of consciousness itself.

Howie said...

I agree with Self Aware Patterns to a point.
What would it mean to say dream skepticism has a 25 % credence versus a 75% credence?
True Descartes I recall in the Meditations saw some reasons to doubt he existed stronger than others; but it is hard to quantify, even with a Likert scale.
Not sure that degrees of credence would be that meaningful; a 25 % chance I am dreaming would be equivalent to a 25 % chance of rain? In 1 out of 4 worlds I'd be dreaming?
It does seem hard to be meaningfully precise and seems subjective.
What are the chances I'm a character in a movie? It's imaginative and fun and like a game, but how can you quantify imaginary scenarios?

Paul D. Van Pelt said...

A professor has held an interesting view on something he calls credence. Another term, from the same root (far as I know) defines or perhaps refines believable. Related terms include evidence, proof etcetera. Last I read, the professor theorizing on this was getting skepticism in his own right. Does anyone know to whom I am referring and does that matter have currency here? I am not racing any horses or hunting with dogs---just curious at the relative temporal proximity of these developments. A clue for you: the professor was once closely associated with another blog I have read often, but not so often now.

Arnold said...

Wisdom for certainty...
...credibility skeptibility believability for uncertainty...

Aside...when you've written 'external' in this post today...
...were you posing internal at the same time...

Anna Strasser said...

Great post! My credence assignment regarding your view increased by reading this. However, it is still an open question to me how we can evaluate the credence people decide to give certain scenarios.
Imagine you come to the point where you decide to give a high credence to the scenario that you are really just dreaming because you gained the insight that treating your life as a dream has much more advantages than disadvantages for you even though you have to change many other beliefs that had a high credence for you. You might act in a way that appears weird to others; I might say you are delusional. Presupposed your belief is elaborated enough, I am sure that you can integrate all kinds of reactions.
And then we would have again a case, in which a scenario that most people give nearly no credence to, should be discussed. My not-yet thought-through guess is, that your credence assignments have a neat connection to the credence assignments of all your social interaction partners. It seems to be easier to assign high credence to a scenario if you can reassure yourself that others share your credence assignments. Maybe I missed the point – but maybe it is so that we naturally cannot exclude that everything is completely different than we thought but it is just enough for us if we can be sure (for whatever reason) that we can agree that many people act as if it is like we think. I do not need to be sure whether I have a free will, it seems sufficient to me if many treat me as if I had a free will.

Phil Tanny said...

Anna Strasser writes...

"It seems to be easier to assign high credence to a scenario if you can reassure yourself that others share your credence assignments."

Yes, that seems to be how it works much of the time. We feel that we're reasoning, but just as likely we're referencing the authority of the group consensus.

A real world example of this is tailgating on the highway. It makes no sense at all, because tailgating is risking everything in exchange for nothing. But we see almost everybody else doing it, and unconsciously assume that if it's normal, it must be right.

A lot of human behavior seems to fall in to this category.

Paul D. Van Pelt said...

Loved your comments on tailgating! Seems an appropriate remark to me, exemplifying practical ethics. I have held that the world at large is fixated on excess, exaggeration and extremism, emerging from interests, preferences and motives. Someone else' insurance had to shell out twenty-three hundred dollars to fix my wife's car, after a less-than ten mile an hour bumper thumper. Could have been avoided, had that driver been paying attention. Thanks for the earth bound wisdom.

Arnold said...

I should have mention susceptibility also is uncertainty...
...that certainty uncertainty is the empirical world of (our) being (here)...

Paul D. Van Pelt said...

Susceptibility as uncertainty? I don't agree with that assessment. Different terms, different meanings. It may not be certain that I am susceptible to Covid, if unvaccinated, but neither is it certain I will contract Covid, without inoculation. More likely, yes---not certain. As any human being---possibly other animals---I AM susceptible to Covid. It is not certain I shall get it. Nor that I would die from it, if I did. I get recommended boosters, just in case...a practical variation on Pascal's Wager. Everyone else 'has their own album to do'; 'axe to grind';'horse to race'. Further, affiant sayeth not.

Eric Schwitzgebel said...

Thanks for all the comments, folks!

Clayton: Interesting point and examples. I've seen similar discussions in philosophy of law about the difference between probabilistic evidence vs eyewitness evidence . Probabilistic evidence is often considered insufficient for conviction even when what would seem to be the justifiable credence is higher than one would get from hearing an eyewitness testimony (given the possibility of error in eyewitness testimony). I'm inclined to think this is quite a thorny tangle.

Phil: The idea that more knowledge is generally better is commonly accepted, I agree, and worth further scrutiny.

Mike/SelfAware / Howie: Perhaps needless to say, I agree with Mike. Artificial precision isn't the point, but it's useful to track the difference between "I don't know" as a mere shoulder shrug of approximate indifference vs "I don't know" as near certainty but admission of the tiniest smidgen of doubt vs. somewhere between.

Steven: I'm inclined to agree. But I think the shoe could also go on the other foot. Conclusive refutation of the idea of anything beyond the physical would also deserve a Nobel!

Dan: Philosophy of language is an interesting parallel. One might be interested in reference in general, or one might be specifically interested in the specific objects. Usually philosopher of language are interested in the more general case, but there will be some cases where the specific object is the center of interest instead (e.g., recent discussions about the referent of "woman").

Anna/Phil: Yes, probably most of us find it reassuring when others approximately agree with our credences. Me too! I'm glad we all see to agree on this. One of the weirdest and most discomfiting forms of skepticism, I think, is when you permit yourself to doubt that the person you seem to be having a conversation with actually exists.

Phil Tanny said...

Eric writes..

"The idea that more knowledge is generally better is commonly accepted, I agree, and worth further scrutiny."

What is my degree of belief or confidence in your assertion above?

I guess the first step for me, given I don't know you very well, would be to dial down my skepticism, and not automatically lump you in with all the other academics ignoring this topic. Ok, I can do that, for awhile, open mind and listening here.

The next step might be to suggest an experiment which could help us better understand what we both mean when we agree on the importance of further scrutinizing our relationship with knowledge.

My personal ideal philosophical fantasy would be an online discussion forum dedicated to this topic, filled with a couple hundred academics, and any members of the public who can write reasonably coherently on this subject. That is, apply further scrutiny in earnest.

I'd be delighted to drop all my other projects so as to focus on helping to create such a place. I have the required skills, and would pay for the hosting etc. However, I'm unclear whether my participation would be an aide or obstacle in attracting academics. Probably the later. Ideally academics would establish such a site themselves.

If we believe that our relationship with knowledge merits further scrutiny there's nothing stopping us from doing that. Well, no, that's wrong.

What's stopping us is the widely held assumption across the land of philosophy that our relationship with knowledge is just one of a thousand topics of equal importance.

What is your degree of belief or confidence in that assertion?

Howard said...

So Eric:

You replace knowledge with credences, so we never know anything we just have levels of credences? How do we take into account our assumptions then?

Paul D. Van Pelt said...

I find myself trying to piece this all together. So, I take higher ground: knowledge, where irrefutable, is pretty solid. Fair enough? Credences are akin to beliefs, in any practical sense, usually---as with knowledge---requiring proof to attain validity. Assumptions are tentative. These, colloquially, 'make an ass of you and me'
There you have it. Not so bad, right?

Paul D. Van Pelt said...

Yep. Pretty much. Martin Heidegger wrote about dasein. He is considered among the great philosophers, by many. Not my concern. I found his ideas confusing. And so it goes. Young philosophy PhDs lament the time required to attain tenure track positions at reputable universities, thinking that the brilliance of a dissertation, attainment of a doctorate, must certainly assure success. It is only philosophy, students. And as, if not more, competitive as anything else you may have chosen to learn about. It is not rocket science---achievements, or failures, in that field are demonstrable: things blow up; break down; fall apart or wear out. Philosophy emerges, advances, re-organizes, is subsumed, and re-emerges. And the world just goes on, as if nothing happened. My advice: don't mess with philosophy. Unless you just want to have fun.

Clayton Littlejohn said...

"Clayton: Interesting point and examples. I've seen similar discussions in philosophy of law about the difference between probabilistic evidence vs eyewitness evidence . Probabilistic evidence is often considered insufficient for conviction even when what would seem to be the justifiable credence is higher than one would get from hearing an eyewitness testimony (given the possibility of error in eyewitness testimony). I'm inclined to think this is quite a thorny tangle."

Hey Eric,
Fwiw, I had those kinds of cases in mind. It's not clear to me whether the cases involving emotions and reactive attitudes are the cart or whether they're the horse, but I sort of suspect that this attitude towards the legal cases are at least connected to the idea that certain findings are supposed to express blame, assign responsibility, etc., and that requires at the very least that it's possible that we know certain things. (My hunch is that the connection between knowledge and findings of guilt derive from more basic connections between knowledge and blame and the like, but I don't understand why there's this widespread enthusiasm for knowledge that's not connected to the links between knowledge and emotion, the satisfaction of curiosity, etc.)

Arnold said...

Contrasting philosophy of psychology with philosophy of physiology...
...instinct is to sustain, sense is to move, feel is to breath, thought is to measure...

Is it function for or to behavior, then...

Is it behavior to or for function, then...