Universal Skepticism Debunked — Guest Post by The Cranky Professor

Universal Skepticism Debunked — Guest Post by The Cranky Professor

Universal Skepticism and Its Problem with Pulling Goal Posts on Every Knowledge Claim

Universal skepticism (otherwise known as absolute skepticism or global skepticism) is the view that real knowledge is impossible. This idea can be expressed in different forms. It can be expressed as saying that we have knowledge of nothing or that we really don’t see whether our ideas have any correspondence with reality. Or, it could be expressed as the notion that radically all our justified beliefs can only be probable but not “absolutely certain” or completely certain. Sometimes universal skepticism may be described as a person that follows a principle that puts all judgments under doubt or the possibility of error.

At any rate, a universal skeptic is one who thinks that complete knowledge or certainty of anything is impossible and that there is always of possibility of being mistaken about something — whatever the problems there may be in defining a “possibility of being mistaken” as such. Instead of starting with some apparent, unshakable truth about experience like Descartes’ “Cogito Ergo Sum” or Aristotle’s emphasis on sense-experience, I will bring up an imaginary dialogue that will illustrate a few problems within universal skepticism. Enjoy the reading!

Universal Skeptic: We cannot know anything for certain. There’s always a possibility of being mistaken no matter how slight that possibility may be. I may have 99.99% certainty of a highly probable idea but there’s always a slight chance of being wrong. Not even my own existence is certain. After all, what would it mean to “exist” in the first place?

Skeptic of the Univ. Skeptic (SKOTS): So there’s no such thing as “absolute certainty” or “complete certainty” given your position? I could feel subjectively, completely certain of something but I could only objectively have, say, 98% certainty or 99% certainty of some idea. But I could never have complete, 100% certainty of any true proposition. Is that right?

Univ. Skeptic: That’s right. Real, objective certainty doesn’t exist. It’s just for people that are too opinionated and dogmatic on various matters like politics or whatever else.

SKOTS: So you can never be certain of anything including something obvious and that seems to have no possibility of error and cannot be overridden by future evidence like white is a color and white is a different color from black? Is that so?

Univ. Skeptic: That is so.

SKOTS: So are you absolutely certain that there’s no such thing as absolutely certainty? Do you know for certain that there is no knowledge?

Univ. Skeptic: Yes, I’m certain that there’s no certainty or knowledge.

SKOTS: Then why be a universal skeptic, for then you are being inconsistent and are claiming to be absolutely certain of something true here, namely that you know that you don’t know anything.

Univ. Skeptic: Okay, maybe I didn’t express myself adequately. Alright, since knowledge doesn’t really exist, I cannot even know for certain that I don’t know anything. Since it’s consistently true that there’s no 100% certainty of anything, then I cannot even be certain of the fact that I’m uncertain of everything.

SKOTS: Then why believe that proposition of universal skepticism of yours? If universal skepticism could be wrong then you could have 100% certainty of some things in life without perhaps realizing it.

Univ. Skeptic: I guess that’s possible.

SKOTS: But then you cannot prove your position to be true.

Univ. Skeptic: How so?

SKOTS: Well, if you were to prove your proposition to be true, then universal skepticism would not be true. Actually proving universal skepticism to be true would mean that you know something with certitude and that’s inadmissible if you’re a consistent, absolute skeptic. So your victory would be your defeat. If universal skepticism were proved to be true or known with complete certainty then universal skepticism would also be proven to be false since not every proposition would be an unknown. At least one proposition — universal skepticism here — would be known to be true if it were proven to be true. In other words, it would be a contradiction in terms to prove that one knows that one knows nothing at all.

Univ. Skeptic: Okay…but maybe the absolute skeptic can defend their position on merely probable grounds in which case it would still be justified.

SKOTS: Again, the problem with that is establishing that universal skepticism is probable and that it actually has more rational evidence to support it over other propositions in epistemology. Furthermore, wouldn’t the same problem of consistency arise in universal skepticism even if the claim is that it’s only probable? Would the skeptic then be certain that he was claiming his own position to be only “probable” or “likely” the case? All that it takes to make a claim is to simply make that particular claim. And it’s either going to be that the universal skeptic claims their position to be probable or not. And if it’s claimed that universal skepticism is “probably true” then it has to be known with certainty here that it’s being claimed as “probably true.” Or, if it cannot even be known that a claim of probability is being made here even when some position is being defended, then how would absolute skepticism ever be seen as probable in the first place?

Univ. Skeptic: But it still seems to me that universal skepticism is probably true. I mean how many times does a person think they know something and they turn out to be wrong about something? People used to think the earth was flat but now the evidence points to it being spherical. And we cannot have real knowledge of anything if there’s always the chance of being mistaken.

SKOTS: Then oddly enough, you’re not quite certain of the Earth’s shape even with all the modern science! Nor are you even certain that mistakes exist given your view!

Univ. Skeptic: Well, it seems that we do error and we’re fallible people nonetheless. How many times do children make mistakes in school?

SKOTS: True, people do err. But your own position, believe it or not, implies that it’s possible that a mistaken belief can count as a case of absolute certainty.

Univ. Skeptic: What?! How so? What the heck are you talking about?”

SKOTS: Well, first of all, if there’s no such thing as knowledge and I mean no such thing as complete knowledge of any facts out there, then we don’t really know what “absolute certainty” is or what would constitute it. Am I right?

Univ. Skeptic: I guess so.

SKOTS: I mean if knowledge is so problematic and definitions are impossible, and we cannot even know that “white isn’t black and black isn’t white” so to speak, then absolute knowledge can be anything.

Univ. Skeptic: So, your point?

SKOTS: The point being that if universal skepticism is true, then logically we don’t even know what it would be mean to completely certain of anything. We could not even know what knowledge is as such. So, it would be possible as far as we’re concerned that only a probable belief can be a real case of absolute certainty. Likewise, it could be true, as far as we’re concerned, that a wild guess could be a real case of certainty. Moreover, it could be the case that an erroneous judgment like a child mistakenly believing that “2+2=7” is real instance of having absolute certainty. By your position, we don’t know what knowledge is, so as far as we’re concerned, a mistaken belief – a belief that happens to be incorrect – could be a real case of being completely certain of some truth.

Univ. Skeptic: That’s sounds like a contradiction!

SKOTS: That’s because it is a contradiction! But universal skepticism entails that it is possible as far as we’re concerned that such an epistemic contradiction could be the case in reality.

Univ. Skeptic: But I don’t believe it’s possible in reality to be completely certain of the truth of an idea and yet be in error in thinking that same idea is true.

SKOTS: Yes, it’s not possible to have complete, epistemic certainty of the truth of an idea and, at the same time, be wrong in believing that same idea. Knowledge cannot be identified with error or with ignorance. A person cannot be, for instance, absolutely certain of the proposition that 2+2=7 if that proposition is false. But your extreme skepticism entails that we should be open-minded to this type of epistemological contradiction. After all, you claim that we don’t know anything, so by that premise, you don’t even know for sure that an erroneous judgment cannot count as real knowledge!

Univ. Skeptic: What?

SKOTS: Or, you can grant that it’s completely certain and established by the evidence that an error can never be identified with complete certainty. But in that which case, you would no longer be a universal skeptic!

Univ. Skeptic: But I don’t think I want to claim for certain that a mistaken belief cannot be an instance of knowledge.

SKOTS: Then why deny absolute certainty in anything? When the term appears to be empty and vacuous, then why go into all this effort to show that nothing is certain in the first place? And when the term certainty could be identical with any epistemic condition including a mistaken judgment then so much for the hopes of proving the plausibility of absolute skepticism. It seems that the term certainty has been blown out of the realm of intelligibility here!

Univ. Skeptic: Well, I’m not saying that we should affirm the certainty of anything. We need to be open-minded always to a possibility of error!

SKOTS: Yeah that’s precisely the problem with universal skepticism, it encourages us to be open-minded to the point of having our brains spill out so to speak. What would it be like to be uncertain of the fact that an error cannot be a real condition of knowledge? You say there’s always a so-called possibility of error no matter how justified a belief may be and that the future may always correct any belief that we may have. But how? What would it be like to find out anyway that an erroneous belief can be an instance of knowledge? Wouldn’t discovering a belief to be wrong be sufficient proof that the belief formerly held wasn’t a case of iron clad certainty in the first place?

Univ. Skeptic: But aren’t you being too dogmatic and sure of yourself in your ideas here?

SKOTS: Not as “dogmatic” and “certain” as Peter Unger, that famous universal skeptic who practically claimed to be absolutely certain that he wasn’t certain of anything. And when he dealt with the issue of whether he was certain of his own existence, he made the statement that “…I ought never to be certain of these things, no matter how tempting that might be.” Unger argued that any firm knowledge claim was too dogmatic and overstretching one’s certainty. But it never occurred to him that it’s also possible for the dogmatism to go the other way around. One can be too dogmatic and assertive in making claims of ignorance and uncertainty. Claims of being ignorant can be bogus as well.

(Unger quoted in Epistemology: An Anthology, by Ernest Sosa & Jaegwon, Blackwell Publishing 2004, P. 51)

Univ. Skeptic: I think I’m done arguing with you. You seem to twist my ideas around anyway.

SKOTS: Well, let me ask you one last question.

Univ. Skeptic: What?!

SKOTS: Do you have any idea on how certain facts, or let’s say beliefs, that can be mistaken like “an erroneous belief cannot be real knowledge” or “White is not black” or one’s consciousness or that “number 3 is not the same number as 4”? And while there may be a lot of strongly justified beliefs that technically can be overridden by future evidence like in the case of scientific theories, there does appear, however, to be beliefs that are so well anchored in solid evidence that it’s practically impossible to be mistaken about these particular beliefs. I mean, there seem to be some beliefs like “white is not black,” or “that 3 is less than 4,” etc., that would still be true even if I were to wake up the next morning and find myself to have been liberated from a matrix or a life long dream. And when the universal skeptic speaks of every belief being suspect of error and wants to pull goal posts on every knowledge claim out there, all this doesn’t describe the epistemic conditions of every belief that we have in life.

Univ. Skeptic: Well, we just have to be open to the possibility of error in every belief that we may have as such. We should always have an open-minded attitude to being corrected with anything.

SKOTS: I’m not talking about what our moral attitude towards ideas should be in general, which is altogether subject to much debate anyway. Some philosophers don’t even consider open-mindedness to be always a virtue. What I asked was about the objective, knowledge conditions of seemingly non-overrideable beliefs like white is not black and 3 is not 4, etc. Universal skepticism is a thesis about our objective epistemic conditions and it’s a proposition that says that we literally know nothing and that we’re always under the risk of error, which seems to be false. How can white, for instance, be the same color as black or red? Let alone, that logical Law of Identity, which says ‘Whatever is, is” and is a logical principle that is presupposed in every idea and argument out there?! How is a mistake possible in such scenarios?

Univ. Skeptic: I don’t know. I have to leave anyway. It’s been nice talking to you…

SKOTS: Okay, bye!

The dialogue illustrates the essential problems of universal skepticism. Of course, it doesn’t present every issue surrounding epistemology, but it shows universal skepticism to be a flawed position. The first mentioned problem with universal skepticism is that that it cannot coherently be justified, argued or proved without presupposing absolute knowledge of either its “truth” or simply the claim that it is true. Even if universal skepticism is argued on merely probable grounds, it seems then the skeptic would be implying that he knows for certain that he’s claiming that universal skepticism is “probably true.” After all, it’s either that the absolute skeptic justifies his position with reasons or he does not. If he justifies it with reasons then he contradicts himself because then he would be implying that he has knowledge of the fact that he is claiming universal skepticism to be true.

Furthermore, universal skepticism implies that there is no such thing as real knowledge or so-called “absolute certainty.” One sometimes comes across this hype about how no belief is ever held with 100% certainty. But that claim comes at a high cost, because when nothing is objectively, completely certain then this leaves it open for the “possibility,” however slight, that an erroneous belief or judgment could be a real case of absolute certainty. After all, if nothing is certain then the meaning and conditions of certainty are unknown as well. And why be open-minded to a supposed “possibility” that a mistaken belief might actually be an instance of real, ironclad knowledge? Such an epistemological contradiction is impossible.

Moreover, there seem to be some beliefs that are so well evidenced that the truth of such beliefs are non-overrideable. One can imagine being mistaken about the age of the universe. But how is it even possible or even coherent to be mistaken with the belief that the color white is not the same color as black? Is it ever possible that black could look exactly the same as white? Also, isn’t number 4 always going to be a greater amount than 3? While many beliefs may have a chance of being mistaken, some beliefs seem to have no real possibility at all of being mistaken. If there are certain beliefs or ideas that cannot be wrong or have no detectable way of being mistaken then this seems to refute universal skepticism.

Overall, I would say that the classic argument that universal skepticism is incoherent is a sound argument. If nothing is known for certain then is universal skepticism itself known with certainty? If it is claimed to be known with certainty then we have a contradiction. It would no longer be true that every idea is uncertain if it’s certain that we have no knowledge. So the universal skeptic may deny having knowledge of his own position to keep his skepticism consistent. But is universal skepticism made consistent even when the skeptic makes this concession? Certainly not. This is because if it’s the case that every proposition cannot be known for certain, including universal skepticism, then one thing would remain absolutely certain by implication, viz., that no idea out there can be certain. If knowledge has to be denied of every possible idea laid out there then it would be certain that no idea can be known for certain. Thus, the claim to have no knowledge at all collapses to having a complete knowledge of that claim itself. Hence, universal skepticism is not a coherent position.

For these reasons and many other reasons, I don’t find universal skepticism to be true. Consider me a skeptic of universal skepticism!

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  1. Sheri

    I thought only God knew things with 100% certainty….Apparently, humans have achieved Godhood.

  2. Nate

    What about almost-universal skepticism, which is the same except you carve out an exception for the claims of universal skepticism itself?

  3. robert

    Universal skepticism can also be viewed as a First Principle, but as JH Newman says — as a First Principe –much of what you know is mostly right so you should rather refine what you know than reject it all. It’s really just a “My football team is better than yours” “argument”. So I let those people be.

  4. Ken

    Yep, you can’t be certain of anything, except where you can.

    Philosophers need to learn to write for T-shirts or fortune cookies. Lots more words don’t make the point any more profound.

  5. Gary


    A more important issue is distinguishing truth from falsity when one has limited knowledge.

  6. Dean Ericson

    ”…real knowledge is impossible.”

    It’s impossible to know that.

  7. Yonason

    We never sent men to the moon and brought them home. How could we have, if we don’t know anything? We just imagined it. Must have been something in the water.

  8. DG

    “I thought only God knew things with 100% certainty….Apparently, humans have achieved Godhood.”

    Uh so you know that with 100% certainty? If not, then I guess it’s possible that we could be these “gods” out there that at least know some things! Or, can God make a mistake while being omniscient?

    Let alone, who’s going to question the fact that errors and human fallibility exist to begin with as such? Isn’t realizing that mistakes sometimes happen knowing something there?

  9. vince

    Two rongs
    don’t make
    a ladder

  10. I dropped a hammer. It fell on my foot. It hurt. I know these three facts with 100% certainty. I can establish cause and effect from fact #1 through fact #3. I can infer other truths from them, such as the existence of gravity and some evidence about the human nervous system. It also proves the existence of hammers, which imply a maker (or makers) of hammers. The hammer required raw materials from which to shape it. It also proves the existence of me, which is a far more complicated topic, involving discussions of what, precisely, does “clumsy” mean?

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