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A response to the argument that scepticism is self-refuting/selfcontradictory

Amalac April 08, 2021 at 16:07 11775 views 53 comments
Being tired of seeing that a significant number of philosophers and other people tend to think that the problems raised by philosophical scepticism can be solved by just saying: “Well, if the arguments/claims of sceptics are valid/true, then they would refute themselves, therefore they can't be valid/true”, (and that's it! They think that's all it takes to solve the problems of scepticism that have troubled many of the greatest philosophers for so many years!) which seems to me to be a lazy and simplistic response, I have written this thread:

One of the arguments used against skeptics since the times of ancient Greece and down to the present day, starts from the following implication: "If there is no proof, there is proof" (¬p ? p)

They say that it must necessarily be true, because if the skeptics affirm without proof that there is no proof, they would be as untrustworthy as those who affirm without proof that proof exists. And if they affirm it with a demonstration, they are contradicting themselves, because then there would be at least one demonstration: the one proving that there is no proof.

The ancient skeptics themselves have already responded to this argument in Adversus Mathematicos and in Outlines of Pyrrhonism.

I for my part will give a somewhat different answer to that argument:

Let p be: "Proof exists" (Meaning: “There is at least one proof”).

1: ¬p (Sceptical hypothesis)

2:¬p is equivalent to ¬ (p v p) (1, Idempotent Law)

3: ¬(p v p) is equivalent to ¬(¬¬p v p) (2, Double negation)

4: ¬(¬¬p v p) is equivalent to ¬ (¬p ? p) (3, Implication)

5: ¬p is equivalent to ¬(¬p ? p) (1,2,3,4 Transitivity)

6: p v ¬p (Law of the Excluded Middle)

7: ¬p ? ¬p (6, Implication)

8: ¬p ? ¬(¬p ? p) (5,7 Substitution)

9: ¬p ^ [¬p ? ¬(¬p ? p)] (1,8 Conjunction)



This shows that there is no logical contradiction in denying the implication ¬p ? p if proof does not exist, and therefore those who disagree with the sceptics cannot hold that the implication ¬p ? p is true to show that p is true without begging the question, since this implication is only true if p, that is: "Proof exists", is true.

It will be answered: "But what you have just done here is certainly a demonstration, therefore there is at least one demonstration." Then the skeptic will answer: But if what I just did is a proof, then its conclusion: ¬p^ [¬p ?¬(¬p ? p)] must be true, therefore ¬p is true, therefore ¬(¬p?p) is true, therefore (¬p?p) is false, therefore ¬p is true and p is false.

The problem is that logic seems to self-destruct, and the skeptic then asks: Where is the error in [Insert here a seemingly valid argument that has “therefore there is no proof” as its conclusion, that the opponent of the sceptic has criticised by saying that ¬p?p] then? Since if the conclusion follows from the premises, and the premises are admited to be true, then the conclusion, “proof does not exist”, must also be admited.

He would continue: “I myself admit that I do not know if there is an error or not, nor if what I have just stated is a proof , but my argument is that by not being able to determine even if proof is more likely to exist than for it not to exist, we should suspend judgment”

David Hume, in the conclusion of section I of his Treatise of Human Nature, understood the problem quite well:

If the sceptical reasonings be strong, say they, ’tis a proof, that reason may have some force and authority: if weak, they can never be sufficient to invalidate all the conclusions of our understanding. This argument is not just; because the sceptical reasonings, were it possible for them to exist, and were they not destroy’d by their subtility, wou’d be successively both strong and weak, according to the successive dispositions of the mind. Reason first appears in possession of the throne, prescribing laws, and imposing maxims, with an absolute sway and authority. Her enemy, therefore, is oblig’d to take shelter under her protection, and by making use of rational arguments to prove the fallaciousness and imbecility of reason, produces, in a manner, a patent under her hand and seal. This patent has at first an authority, proportion’d to the present and immediate authority of reason, from which it is deriv’d. But as it is suppos’d to be contradictory to reason, it gradually diminishes the force of that governing power, and its own at the same time; till at last they both vanish away into nothing, by a regular and just diminution. The sceptical and dogmatical reasons are of the same kind, tho’ contrary in their operation and tendency; so that where the latter is strong, it has an enemy of equal force in the former to encounter; and as their forces were at first equal, they still continue so, as long as either of them subsists; nor does one of them lose any force in the contest, without taking as much from its antagonist. ’Tis happy, therefore, that nature breaks the force of all sceptical arguments in time, and keeps them from having any considerable influence on the understanding. Were we to trust entirely to their self-destruction, that can never take place, ’till they have first subverted all conviction, and have totally destroy’d human reason.


Yet even Hume appears not to have been thoroughgoing enough: Just because in the past our nature has been such that sceptical reasonings haven't had a considerable influence on our understanding, that doesn't mean that in the future they won't have a considerable influence in our minds. As Bertrand Russell pointed out:

(...)the law of habit is itself a causal law.
Therefore if we take Hume seriously we must say: Although in the past the sight of an apple has been conjoined with expectation of a certain kind of taste, there is no reason why it should continue to be so conjoined: perhaps the next time I see an apple I shall expect it to taste like roast beef. You may, at the moment, think this unlikely; but that is no reason for expecting that you will think it unlikely five minutes hence. If Hume's objective doctrine is right, we have no better reason for expectations in psychology than in the physical world.

Comments (53)

Zophie April 08, 2021 at 16:11 #520218
Cool but.. can't you prove anything from a negation?

If these philosophers believe the truth is a real thing, aren't they trying to refute a tautology? Why bother?
Amalac April 08, 2021 at 16:20 #520223
Reply to Zophie

Quoting Zophie
Cool but.. can't you prove anything from a negation?


I suppose you are talking about the Principle of Explosion (Ex Falso Quodlibet). Indeed, if the statement “there is no proof” were false, then you could prove anything from it. But that's only if it is false (that has to be proven first). The problem is that some try to argue that it is false by saying that if it were true, then it would be false, which contradicts what seemingly valid logical reasoning tells us.

Quoting Zophie
If these philosophers believe the truth is a real thing, aren't they trying to refute a tautology? Why bother?


Which philosophers are you refering to here, the sceptics or the non-sceptics? Also, which tautology are you refering to?
Zophie April 08, 2021 at 16:26 #520225
I notice your explanation of there being proof prequires provability, which, like all deduction, involves a signal conversion to new rules that isn't licenced by the prior system. It is just given.

Those are the kind of tautologies I mean.
ernest meyer April 08, 2021 at 16:34 #520226
Reply to Zophie
I can understand there being concern about it, because there are obvious cases when skeptics are hypocritical. For example, Chomsky was a prolific user of media in saying that media deliberately falsifies explanations as propaganda, making himself a propagandist. But I dont think there should be any doubt that logic would reach the conclusion that skepticism does not refute its own existence, because it's predicated on the existence of negation in the first place, lol. Skeptics just feel there are more cases where conclusions are false.
Zophie April 08, 2021 at 16:39 #520230
Quoting ernest meyer
Chomsky was a prolific user of media in saying that media deliberately falsifies explanations as propaganda, making himself a propagandist.

If so, does this not just further demonstrate what he said was true? He would be the one to know.
ernest meyer April 08, 2021 at 16:55 #520236
Reply to Zophie to Chomsky what he said was true. To others he should be a propagandist by his own definition. lol.
Zophie April 08, 2021 at 16:59 #520241
Reply to ernest meyer Should -- if you presume an argument from commitment is relevant.
Amalac April 08, 2021 at 17:00 #520242
Quoting Zophie
I notice your explanation of there being proof prequires provability, which, like all deduction, involves a signal conversion to new rules that isn't licenced by the prior system. It is just given.



Hmmm, not entirely sure what you are saying here.

Are you saying that the argument/ proof proving that there is no proof assumes that proof is reliable, and therefore refutes itself?

If so, what would be your response to the passage by Hume I quoted in the OP?


Amalac April 08, 2021 at 17:02 #520243
Reply to ernest meyer

Quoting ernest meyer
Chomsky was a prolific user of media in saying that media deliberately falsifies explanations as propaganda, making himself a propagandist


You are generalizing a bit too much. Chomsky says many people in the media falsify explanations, not that everybody does. Some people do not only care about propaganda.

But anyway, we're already getting off topic.
ernest meyer April 08, 2021 at 17:07 #520247
Reply to Amalac well, in that case, he should have defined what is different about his view that doesn't make it propaganda, but he didn't, he just complained all the time. But I agree, how much should one care whether the opinions of populist philosophers are coherent. I just stated that it is a natural tendency to think that skepticism is self-falsifying, because many skeptics are similarly hypocritical, but it doesn't seem to me to need much more than to say skeptics just believe more conclusions are false, and there's nothing wrong with that.
Zophie April 08, 2021 at 17:08 #520248
Reply to Amalac I'm assuming the modern, deductive meaning of proof, and yeah. Ultimately, it provides no new information. It rearranges what is already known. It's a method of translation, not of truth in the traditional sense. Speaking of translation, I don't know what Hume is talking about.
Amalac April 08, 2021 at 17:18 #520253
Reply to Zophie

Quoting Zophie
Speaking of translation, I don't know what Hume is talking about.


Really now... I thought he was quite clear.

What about this passage of Sextus Empiricus?:

(...) just as it is not impossible for the man who has ascended to a high place by a ladder to overturn the ladder with his foot after his ascent, so also it is not unlikely that the Sceptic after he has arrived at the demonstration of his thesis by means of the argument proving the non-existence of proof, as it were by a step-ladder, should then abolish this very argument.
Amalac April 08, 2021 at 17:22 #520255
Quoting Zophie
It rearranges what is already known. It's a method of translation, not of truth in the traditional sense.


I should clarify that the argument in the OP is not one for the conclusion that “proof does not exist”, but rather for the claim that it is not necessarily inconsistent to deny the proposition “proof does not exist, implies that proof exists”, if indeed “proof does not exist” were true.
Zophie April 08, 2021 at 17:33 #520259
Quoting Amalac
I should clarify that the argument in the OP is not one for the conclusion that “proof does not exist”

I'm merely suggesting that the method of deductive proof is generally trivial. In my humble opinion a skeptic may be better served by moving to a relativist model since that allows the following phrasing:

Skepticism says the truth of everything is doubtable to a skeptic, but if that is true, the truth of skepticism is doubtable to a skeptic, therefore skepticism says the truth of skepticism is doubtable to a skeptic because skepticism is doubtable to a skeptic (and that is a something, and every something is doubtable). All of this is trivially true. A positive phrasing reveals the absurdity of that kind of argument.
Amalac April 08, 2021 at 17:43 #520270
Quoting Zophie
All of this is trivially true.


Do you think it is trivially true that logic should seemingly allow anyone (not just the sceptic) to validly conclude something that contradicts logic itself, and that in case the argument that proved that which contradicts logic were invalid, it was also such that we have difficulties pointing out where its error is? Well, I don't agree with that. If you do, then there is nothing else I can reply to you.
Zophie April 08, 2021 at 17:46 #520272
Reply to Amalac You misunderstand. The question is not 'logic?' but 'which logic? (and for what?)'. :)
Amalac April 08, 2021 at 17:53 #520278
Reply to Zophie

Quoting Zophie
'which logic? (and for what?)'


Let's take a logic that has as its basis: The Law of Contradiction, The Law of the Excluded Middle, The Law of Identity, and principles of inference such as Modus Ponens, De Morgan's Law, etc. And also one that believes that some statements can always be validly proven by using those laws and principles.

For example: aristotelian logic, mathematical logic, etc. Not a paraconsistent logic.

Don't you think the arguments of sceptics give important objections to those systems, even if their arguments were invalid?

Zophie April 08, 2021 at 18:00 #520283
I think the arguments of skeptics -- using those systems at least -- give trivial subjections to those systems that resolve to the thesis that not even logic can disprove logic, and that this is expected because it's a sign that the logic of those systems is true.
Amalac April 08, 2021 at 18:19 #520290
Reply to Zophie Quoting Zophie
I think the arguments of skeptics -- using those systems at least -- give trivial subjections to those systems that resolve to the thesis that not even logic can disprove logic, and that this is expected because it's a sign that the logic is true.


Ok, let's try this approach instead: Surely you'd say that sceptical arguments such as the argument that uses Agrippa's Trilemma to conclude “therefore there are no proofs” are invalid/unsound.

But why is it invalid/unsound? Is one of the premises false? Does the conclusion not follow from the premises? At least one of those must surely be true according to those systems. If not, then according to logic it must be valid and sound, and therefore its conclusion “Therefore there are no proofs” must be true (since otherwise it would not be valid and sound). According to logic, we should be able to pinpoint the error in that argument, and also in the argument which concludes that if not p (p= There is at least one proof), then it's not the case that not p implies p.

You say the sceptical arguments resolve to the thesis that not even logic can disprove logic, but how do you know this? How did you come to that conclusion? How do you know that it is not instead how Sextus or Hume say it is?:

(...) just as it is not impossible for the man who has ascended to a high place by a ladder to overturn the ladder with his foot after his ascent, so also it is not unlikely that the Sceptic after he has arrived at the demonstration of his thesis by means of the argument proving the non-existence of proof, as it were by a step-ladder, should then abolish this very argument.


Zophie April 08, 2021 at 18:26 #520291
Quoting Amalac
Surely you'd say that sceptical arguments such as the argument that uses Agrippa's Trilemma to conclude “therefore there are no proofs” is invalid.
At face value, no. I would say it needs another element to make it properly analyzable, though.
Quoting Amalac
How did you come to that conclusion?
I didn't. It's set by the definitions of every well-defined system.

Amalac April 08, 2021 at 18:35 #520298
Quoting Zophie
At face value, no. I would say it needs another element to make it properly analyzable, though.


Ok, what is wrong with the argument that has the horns of the Trilemma as its premises and “Therefore no claim is justified” as its conclusion? According to those systems of logic, it must be either invalid or unsound (either at least one of the premises is false, or the conclusion does not follow from the premises). There is no third option.

Quoting Zophie
I didn't. It's set by the definitions of every well-defined system.


Really now, which set of definitions are you refering to? Why should one accept the implicit premises in those definitions, such as those which already assume, right off the bat, that nothing can ever disprove logic, not even logic itself? Such definitions would in that case just assume that the sceptic can't refute logic using logic, but why should the sceptic accept them then?
Zophie April 08, 2021 at 18:46 #520304
Quoting Amalac
what is wrong with the argument that has the horns of the Trilemma as its premises and “Therefore no claim is justified” as it's conclusion?
It's unrealistic. Propositions may be true/false but any actual proposition is defeasible.
Quoting Amalac
why should the sceptic accept them then?
I don't know, why should they? Because they do? Because they can?
Banno April 08, 2021 at 21:43 #520368
Quoting Amalac
One of the arguments used against skeptics since the times of ancient Greece and down to the present day, starts from the following implication: "If there is no proof, there is proof" (¬p ? p)


Wouldn't it have been simpler to point out that this leads directly to a contradiction, and hence is invalid?

More interestingly, who are the Greeks and others who used such a silly argument?
Bartricks April 08, 2021 at 22:03 #520379
Reply to Amalac It seems to me that you are arguing that there is no contradiction involved in the sceptical thesis and thus that the sceptical thesis is not self-refuting. (Unless I have misunderstood).

But although I accept that there is no contradiction involved in the thesis, I take it that a theory is 'self-refuting' when there would be a practical contradiction involved in believing it. So, for instance, "I do not exist" would be a self-refuting theory for anyone to hold, even though there is no contradiction involved in the thesis. If I hold it, I do exist. And "It is raining, but no one believes it is raining" would be another, as although it is possibly true - there seems nothing impossible about the scenario described - to believe it is to render it false.

The charge against radical scepticism is surely that it is self-refuting in this way. That is, it is not that the thesis describes an impossible scenario. Rather, it is that anyone who believes it is justified, is confused: for if it is indeed justified (as it could be), then it is false.

I suppose you might respond that this does not establish that radical scepticism is false, just that believing it is something we can never have epistemic reason to do. (For if it is true, then we have no epistemic reason to believe it; and if it is false, then we have no epistemic reason to believe it, because one can only have epistemic reason to believe a proposition if it is true).

However, I take one of Descartes' lessons to be that self-refuting positions are more certainly false than those that contain contradictions. For I know more certainly that I exist, than that the law of non-contradiction is true. And so when we have shown that it would be self-refuting to hold a particular view, we have established that to hold it would be to hold a false view.

Amalac April 08, 2021 at 22:19 #520392
[Reply to Banno

Quoting Banno
Wouldn't it have been simpler to point out that this leads directly to a contradiction, and hence is invalid?


Their argument is that the argument the sceptic uses proves the sceptic's conclusion “therefore, there are no proofs”, and therefore refutes itself, because if there is no proof, then the sceptic's argument is not a proof either. They then conclude that it's impossible for the statement “No statement can be proven” to be true, since if it were, then that would imply a logical contradiction.

Quoting Banno
More interestingly, who are the Greeks and others who used such a silly argument?


They are refered to as “the dogmatists” by Sextus Empiricus. I assume he means, based on the people he references in “Outlines of Pyrrhonism”, philosophers from the school of Plato, Aristotle, and/or stoic philosophers, of his time and of earlier times.
Banno April 08, 2021 at 22:36 #520397
Quoting Amalac
“the dogmatists”


Where?

Here's a of Outlines of Pyrronism; where is this argument?

Amalac April 08, 2021 at 22:43 #520402
Reply to Banno

Quoting Banno
Where?


Pages 88-89 (185) in the pdf you linked, it starts saying: It will suffice to have said this much...at the end of page 88
Amalac April 08, 2021 at 22:47 #520405
Reply to Banno

Quoting Amalac
Pages 88-89 (185) in the pdf you linked, it starts saying: It will suffice to have said this much...


That's where it starts I mean, Sextus finishes talking about it in page 90.
Banno April 08, 2021 at 22:54 #520409
Reply to Amalac Thanks.

So we have this:
If there is a proof, there is a proof.
If there is no proof, there is a proof.
Either there is a proof or there is no proof.
Therefore, there is a proof.


The second premiss is surely a contradiction, no?

SO yes, it is a bad argument. But it's far from the only argument against scepticism.
Amalac April 08, 2021 at 23:02 #520412
Reply to Banno

Quoting Banno
The second premiss is surely a contradiction, no?


Well, ¬p?p is equivalent to: ¬¬p v p, which is just p (Proof exists), according to the rules of material Implication, double negation and the idempotent law. So in that sense, I suppose it's not a contradiction.

Quoting Banno
SO yes, it is a bad argument. But it's far from the only argument against scepticism.


I didn't say it's the only one, but it's one very commonly used in the internet and by many philosophers. If you don't believe me, lookup videos on that subject and what philosophers have said about scepticism, and I'm sure you'll find many people using it.
Banno April 08, 2021 at 23:16 #520414
Quoting Amalac
So in that sense, I suppose it's not a contradiction


Yeah, I agree - I was mistaken.

Amalac April 09, 2021 at 00:04 #520436
Reply to Bartricks

Quoting Bartricks
It seems to me that you are arguing that there is no contradiction involved in the sceptical thesis and thus that the sceptical thesis is not self-refuting. (Unless I have misunderstood).


You have not misunderstood.

Quoting Bartricks
I take it that a theory is 'self-refuting' when there would be a practical contradiction involved in believing it.


I sort of agree in a sense. As Noam Chomsky pointed out, there are no sceptics (in practice).

Quoting Bartricks
However, I take one of Descartes' lessons to be that self-refuting positions are more certainly false than those that contain contradictions. For I know more certainly that I exist, than that the law of non-contradiction is true.


Hmm, I'm not sure if I agree with that. Bertrand Russell describes the status of our knowledge with regards to Descartes's cogito quite well in my opinion:

Descartes's indubitable facts are his own thoughts--using "thought" in the widest possible sense. "I think" is his ultimate premiss. Here the word "I" is really illegitimate; he ought to state his  ultimate premiss in the form "there are thoughts." The word "I" is grammatically convenient, but does not describe a datum. When he goes on to say "I am a thing which thinks," he is already using uncritically the apparatus of categories handed down by scholasticism. He nowhere proves that thoughts need a thinker, nor is there reason to believe this except in a grammatical sense. 


Fernando Savater gives an illustration of this: If you translate the statement “It rains” to spanish, you get “llueve” (the subject dissappears completely). And so, just as we would not argue that there must be something that “rains”, (an “it” in the same sense as an “I”) it may also be argued that it is not necessary for there to be some subject who “thinks”, and that maybe the right way of saying of describing the occurance is: “thinking is happening”, just as we would say “raining is happening”.

There is also the view that the self is merely a bundle or collection of perceptions, since we have no impression of self, and therefore no idea of self (this would be David Hume's criticism). Unless we say that we have an innate idea of the self.

Quoting Bartricks
And "It is raining, but no one believes it is raining" would be another, as although it is possibly true - there seems nothing impossible about the scenario described - to believe it is to render it false.


Well let's start by clarifying: If it is raining and I say “it is raining” , does that imply that I implicitly believe that it is raining? It would seem that way, for otherwise I would not claim it (unless I wanted to tell a lie, if it wasn't raining, and so “I believe it is raining” would be false, and “no one believes it is raining” could still be true).

It is not self-contradictory however, since if the human race perished tomorrow, and it was still raining on earth, then the proposition “It is raining, but nobody believes it is raining” would be true (and not even self-defeating, since it need not be uttered by someone in order for it to be true). But anyway, this is not the right thread to discuss the transcendental notion of truth.

All those points you mention will surely get us off topic, so I won't respond to them further, unless they are more directly related to the OP.








Bartricks April 09, 2021 at 00:30 #520445
Reply to Amalac Quoting Amalac
All those points you mention will surely get us off topic, so I won't respond to them further, unless they are more directly related to the OP.


Well, I suppose what I'm saying is that you're conflating 'self-refuting' with 'contains a contradiction'. When philosophers dismiss radical scepticism on the grounds that it is self refuting, they are not thereby asserting that the thesis contains a contradiction. Yet that's what you've taken them to be doing and then proceeded to address that straw man argument.

It seems clear enough that radical scepticism - which I will understand to be the view that there are no reasons to believe anything - contains no contradiction. So I do not believe that there are many philosophers who would claim otherwise.

The claim, rather, is that it is 'self refuting'. "It is raining, but nobody believes it is raining" is one such thesis. It contains no contradiction. But it is self-refuting, for to believe it is to render it false.

The same is true where "there is no reason to believe anything" is concerned. For someone who believes it must, if they are not confused about the nature of what they believe, understand that this means there is no reason to believe that there is no reason to believe anything. This person therefore believes something and at the same time believes that they have no reason to believe it.
As Hitchens put it once, "what we have no reason to believe, we can dismiss without reason" or something like that.
Well, that applies to normative scepticism. The normative sceptic believes there are no reasons to believe anything, including that there are no normative reasons to believe things. They are, then, irrational. Not that they'll care, of course.
Amalac April 09, 2021 at 00:46 #520448
Reply to Bartricks

Quoting Bartricks
So I do not believe that there are many philosophers who would claim otherwise.


I have given a quote by Sextus Empiricus (the one Banno wrote), as well as the Hume quote in the OP, that show that a significant number of philosophers in the past did claim that, and at present you may find that many people do claim that scepticism is selfcontradictory (not merely impossible to believe). If you don't believe me:

Quoting Amalac
lookup videos on that subject and what many philosophers have said about scepticism, and I'm sure you'll find many people using it.


Quoting Bartricks
The claim, rather, is that it is 'self refuting'. "It is raining, but nobody believes it is raining" is one such thesis. It contains no contradiction. But it is self-refuting, for to believe it is to render it false.


I get your point here, but some kinds of sceptics (phyrronian sceptics, as opposed to academic sceptics for example) would not put forward the argument as a proof that no argument can be proved, or claiming that we should believe that “there is no reason to believe anything”, rather they would mention it so that they could pit the arguments against the claim “there is reason to believe something” against those in favor of it, and then suggest that we should suspend judgement as to whether or not there is reason to believe anything, since we seemingly have no way of knowing one way or the other in view of the apparent equipollence of each opposing arguments. The practical choice between the two would then be a matter of taste, they may say.




Janus April 09, 2021 at 00:51 #520449
Quoting Bartricks
The same is true where "there is no reason to believe anything" is concerned. For someone who believes it must, if they are not confused about the nature of what they believe, understand that this means there is no reason to believe that there is no reason to believe anything.


Yes, but this is tendentiously put: making it out to necessarily be a positive belief when it need not be. It could be phrased "I find no reason to believe anything", without the implicit contradiction that would be involved in asserting "I believe that there is no reason to believe anything".

counterpunch April 09, 2021 at 01:01 #520452
My approach to scepticism is based on the principle of sound reason known as Occam's Razor - which states that it is vain to do with more, that which can be done with fewer. Or, to put it another way, the simplest adequate explanation is the best. Scepticism violates these injunctions by disregarding what is apparent, to propose an explanation that raises more questions than it answers. While sceptical flights of fancy cannot be conclusively disproven; we may indeed, all be brains in jars - and this apparent reality merely an induced illusion, it's easier and more likely to accept that an objective reality exists, and we perceive it as it really is - albeit with limited sensory apparatus.
Bartricks April 09, 2021 at 01:11 #520455
Reply to Amalac Quoting Amalac
I have given a quote by Sextus Empiricus, as well as the Hume quote in the OP, that show that a significant number of philosophers in the past did claim that, and at present you may find that many people do claim that scepticism is selfcontradictory (not merely impossible to believe). If you don't believe me


But who has made the argument you are addressing - so, the argument that radical scepticism contains a contradiction (as opposed to being self-refuting)? (I mean, Sextus and Hume are sceptics, right? So they are not the ones making the argument, they are simply addressing it - but that's not evidence that anyone has actually made it).

Quoting Amalac
I get your point here, but some kinds of sceptics (phyrronian sceptics, as opposed to academic sceptics for example) would not put forward the argument as a proof that no argument can be proved, or claiming that we should believe that “there is no reason to believe anything”, rather they would mention it si that they could pit the arguments against the claim “there is reason to believe something” against those in favor of it, and then suggesting that we should suspend judgement as to whether or not there is reason to believe anything, since we seemingly have no way of knowing one way or the other in view of the apparent equipollence of each opposing argument. The practical choice between the two would then be a matter of taste, they may say.


I do not really follow your meaning here. You accept, I take it, that the thesis that there are no reasons to do or believe anything is self-refuting?
Bartricks April 09, 2021 at 01:14 #520457
Reply to Janus Quoting Janus
Yes, but this is tendentiously put: making it out to necessarily be a positive belief when it need not be.


No, it's just accurate. The person who believes that normative scepticism is true, must also believe that there is no reason to believe that normative scepticism is true, otherwise in what sense do they truly believe that normative scepticism is true? To believe that normative scepticism is true, is to believe that there is positively no reason to believe anything. So they believe that there is positively no reason to believe that there is no reason to believe anything. They're irrational then, right?
Luke April 09, 2021 at 01:17 #520459
There is no proof of anything, and I can prove it!
Janus April 09, 2021 at 01:29 #520461
Quoting Bartricks
No, it's just accurate. The person who believes that normative scepticism is true, must also believe that there is no reason to believe that normative scepticism is true, otherwise in what sense do they truly believe that normative scepticism is true? To believe that normative scepticism is true, is to believe that there is positively no reason to believe anything. So they believe that there is positively no reason to believe that there is no reason to believe anything. They're irrational then, right?


Sure, that applies to the person who believes normative skepticism is true, For a start, the very idea of normative skepticism is self-contradictory, because to hold such a position would be to believe that everyone must hold the same criteria for judgement as oneself, and this would obviously be, contradicting the thesis, a positive belief.

But a person can be a radical skeptic on the more modest basis of finding no reason to believe anything. The two positions are not the same.
Amalac April 09, 2021 at 01:29 #520462
Quoting Bartricks
(I mean, Sextus and Hume are sceptics, right? So they are not the ones making the argument, they are simply addressing it - but that's not evidence that anyone has actually made it).


I suppose you are technically right. I can't (at present) tell you who exactly put forward the arguments mentioned by Sextus and Hume. The fact that they don't give the names of the proponents is also unhelpful.

Maybe they were lying and fabricated the arguments. Personally, I don't see any reason for them to lie about that, but I'm open to that possibility.

Later with more time I'll investigate to see if I can find who advanced the arguments that scepticism is selfcontradictory in antiquity.

Quoting Bartricks
I do not really follow your meaning here. You accept, I take it, that the thesis that there are no reasons to do or believe anything is self-refuting?


Self refuting in the sense you have described, yes. But I meant rather “self-contradictory”. Perhaps I should correct the title.

What I mean is that the academic sceptic makes negatively dogmatic claims such as “No belief can be justified”, “We know nothing”, etc. whereas the phyrronian suspends judgement and doesn't make any claims, neither affirmative nor negative.
Bartricks April 09, 2021 at 01:51 #520466
Reply to Amalac Quoting Amalac
Maybe they were lying and fabricated the arguments. Personally, I don't see any reason for them to lie about that, but I'm open to that possibility.


Don't philosophers do this all the time? Not lie, I mean. But anticipate a range of objections to their own view, and then refute them. However, many of the anticipated objections have not actually been made by anyone.

Quoting Amalac
But I meant rather “self-contradictory”. Perhaps I should correct the title.


I think that's a straw man though, as the view that there is no reason to believe anything clearly contains no contradiction.

Quoting Amalac
What I mean is that the academic sceptic makes negatively dogmatic claims such as “No belief can be justified”, “We know nothing”, etc. whereas the phyrronian suspends judgement and doesn't make any claims, neither affirmative nor negative.


What is the Phyrronian thesis, though? That there is as much reason to believe any given proposition as disbelieve it?
Bartricks April 09, 2021 at 02:14 #520475
Reply to Janus Quoting Janus
Sure, that applies to the person who believes normative skepticism is true, For a start, the very idea of normative skepticism is self-contradictory, because to hold such a position would be to believe that everyone must hold the same criteria for judgement as oneself, and this would obviously be, contradicting the thesis, a positive belief.


I do not know what you mean. Normative scepticism - that is, the view that there are no reasons to do or believe anything - is not self-contradictory. There is no contradiction contained in the idea. But it is self-refuting in that anyone who attempts to defend it will have to assume it is false. It is indefensible, then, as if a defence works, then it is not true (for if there is epistemic reason to believe normative scepticism is true, then there is no epistemic reason to believe normative scepticism is true).

Quoting Janus
But a person can be a radical skeptic on the more modest basis of finding no reason to believe anything. The two positions are not the same.


Not really sure what your point is. Yes, we can distinguish between not being aware of a reason to believe something and positively believing there is no reason to believe something. My cat, for instance, doesn't see any reason to believe anything. But it'd be odd to describe my cat as a sceptic.

Let's assume that normative scepticism - which I will stipulate is the view that there are no reasons to do or believe anything - is false. Well, if that's true, then someone who doesn't see reason to do or believe anything is just suffering from a kind of rational blindness. They don't represent a philosophical position anymore than a visually blind person does.
SteveMinjares April 09, 2021 at 02:16 #520476
The question is the mind being able to accept truth or will our ego deny the truth to continue supporting our own convictions.

The problem is not that proof exists. I believe it does exist. Is acknowledging the proof when you encounter it.

Proof is a threat to convictions and the mind is attached to convictions and ideals. Whatever convictions and ideals we uphold in our minds motivates us to move toward whatever goal we have in mind.

The problem is if you find the proof you may encounter a paradox. If that proof contradicts everything you learned and believe.

You find yourself at a crossroad to accept it and re-evaluate your values and morals. Or deny it in the hopes to maintain a resemblance of inner peace.

But if you are lucky the proof will align with your values. Who knows?

So this raise another question do you have the courage and mental discipline to accept the truth and make your ideal and values expendable? Will you be able to Adapt to the new reality?
Amalac April 09, 2021 at 02:46 #520496
Reply to Bartricks

Quoting Bartricks
However, many of the anticipated objections have not actually been made by anyone.


[quote= David Hume]This I take to be the true state of the question, and cannot approve of that expeditious way, which some take with the sceptics, to reject at once all their arguments without enquiry or examination. If the sceptical reasonings be strong, say they, ’tis a proof, that reason may have some force and authority: if weak, they can never be sufficient to invalidate all the conclusions of our understanding. [/quote]

It seems clear to me that the “they” he mentions is not merely a rhetorical device, but maybe I'm wrong. It really sounds like he's adressing an argument he read or heard about from other philosophers.

I think the same about Sextus.

Quoting Bartricks
What is the Phyrronian thesis, though? That there is as much reason to believe any given proposition as disbelieve it?


I guess the phyrronian could say:

a) That they don't present any thesis

Or

b) Suspend judgement when you can't find out whether some belief is more likely to be true than its negation (which for them is always). This sounds similar to what you say.

In practice, however, the phyrronian can't suspend action and hope to survive at the same time.

Phyrrho held that no line of action could be more rational than any other.

If so, the choice of any action and the choice of any belief would be based on taste, sentiment and custom, as Hume would put it.
Bartricks April 09, 2021 at 04:04 #520500
Reply to Amalac Quoting Amalac
It seems clear to me that the “they” he mentions is not merely a rhetorical device, but maybe I'm wrong. It really sounds like he's adressing an argument he read or heard about from other philosophers.


Yes, but the argument he describes there seems as if it is the self-refutation argument, not the contradiction argument. And Hume's response to it seems confused - he seems simply to be noting that the sceptic is fated to have to appeal to reason to undermine reason's authority, but this is no more than to acknowledge the inevitability of self-refutation, not to answer the charge.
jorndoe April 09, 2021 at 04:30 #520504
If all skepticism is wrong, then anything goes.
Since that's not the case, some skepticism is right.

You might doubt anything, but not everything.

If all skepticism is right, then doubt about skepticism is also right.
Hence, unjustified belief can be right.

Seems the problem is the universal (or unqualified) statements.
Janus April 09, 2021 at 05:09 #520510
Reply to Bartricks

The contradiction consists in saying there is no reason to believe anything, and yet I believe something, if the claim is that one should not believe anything without reason. Otherwise, sure, there would be no contradiction. That's why I specified "implicit".

As to your cat, it is not aware of the possibility of any philosophical standpoints, so your point there is profoundly irrelevant.
Bartricks April 09, 2021 at 05:16 #520511
Reply to Janus Quoting Janus
As to your cat, it is not aware of the possibility of any philosophical standpoints, so your point there is profoundly irrelevant.


Yes, that was the point. So pointing out that there are some who see no reason to believe things - such as my cat - was profoundly irrelevant.

Quoting Janus
The contradiction consists in saying there is no reason to believe anything, and yet I believe something, if the claim is that one should not believe anything without reason.


That's not a contradiction in the thesis, that's self-refutation. You're just saying what I said but putting different labels on things
Amalac April 09, 2021 at 05:28 #520513
Reply to jorndoe

Quoting jorndoe
If all skepticism is
wrong, then anything goes.
Since that's not the case, some skepticism is right.


I see, in that case which parts of scepticism do you think are right? For example, how far are things like Agrippa's Trilemma or the problem of the criterion problematic according to you?

Quoting jorndoe
If all skepticism is right, then doubt about skepticism is also right.
Hence, unjustified belief can be right.


Yes, a statement can be true despite being unjustified. The problem is, we need justification in order to avoid having to randomly guess which beliefs are true and which beliefs are false (and which are neither true nor false).

180 Proof April 09, 2021 at 09:39 #520574
Reply to jorndoe :up: As usual, you beat me to it!
jorndoe April 09, 2021 at 15:47 #520700
Quoting Amalac
in that case which parts of scepticism do you think are right?


I guess that's where the harder work lies.
I don't see any particular reason to doubt we're chatting in English here, for example.
Some trivialities demand less doubt than other (perhaps more sweeping or less clear or evident) claims.

Quoting Amalac
The problem is, we need justification in order to avoid having to randomly guess which beliefs are true and which beliefs are false (and which are neither true nor false).


Right, so justification is typically where the work is.
Why doubt and why uphold? Both could take justification.

Anyway, the usual philosophical drive/search for unqualified principles has just failed in this case it seems.
There's more to the story of skepticism, some sort of demarcation?
Ying April 10, 2021 at 03:34 #520921
Well, if someone states that: "if the arguments/claims of sceptics are valid/true, then they would refute themselves, therefore they can't be valid/true”, then they don't understand what philosophical scepticism is all about. The main claim of classical scepticism is:

"The Skeptic Way is a disposition to oppose phenomena and noumena to one another in any way whatever, with the result that, owing to the equipollence among the things and statements thus opposed, we are brought first to epoché and then to ataraxia"
-Sextus Empiricus, "Outlines of pyrrhonism", book 1 ch. 4.

and:

"After these remarks, our next task is to explain the goal of the Skeptic Way.Now the goal or end is that for the sake of which everything is done or considered, while it, in turn, is not done or considered for the sake of anything else; or, it is the ultimate object of the desires. We always say that as regards belief the Skeptic's goal is ataraxia, and that as regards things that are unavoidable it is having moderate pathè. For when the Skeptic set out to philosophize with the aim of assessing his phantasiai – that is, of determining which are true and which are false so as to achieve ataraxia – he landed in a controversy between positions of equal strength, and, being unable to resolve it, he suspended judgment."
-Ibid. ch. 12

Ascribing epistemological nihilism to all forms of scepticism misses the mark completely and only results in a straw man. Some people are (self-)sattisfied with knocking down straw effigies though.