• Agent Smith
    9.5k
    Agrippa's trilemma aka Münchhausen Trilemma.

    Regarding proofs,

    A. there are only 3 possibilities

    1. Infinite regress (every premise requires an argument; every premise of that argument requires a separate argument; so on ad infinitum)

    2. Axiomatic arguments (assume a specific set of premises)

    3. Circularity (the argument's conclusion is just a restated premise)

    B. None of the three (1, 2, and 3) are satisfactory

    Ergo,

    C. Nothing can be proven

    ---

    Refutation

    If Agrippa's trilemma is a sound argument, all arguments fail including Agrippa's trilemma itself [self-refutation; Agrippa, you just shot yourself]

    ---

    Refutation of the refutation of the refutation ...

    1. To claim Agrippa's trilemma is self-refuting I have to craft an argument, call it X, to do so but since I assumed Agrippa's trilemma for that, I've conceded that no argument will do the trick and that includes argument X. In other words the refutation itself is self-refuting.

    Intriguingly, this refutation of the refutation is itself self-refuting for the same reason; however dogmatists are still not out of the woods because the refutation of the refutation of the refutation is also self-refuting, again for the same reason ... ad nauseum/ad infinitum :vomit:

    2. If I use reason to prove reason's worth it would be a circulus in probando (picture baron Müchhausen extricating himself out of the marsh by pulling his own hair).

    WTF? :chin:
  • Paine
    2k


    Euclid did pretty well with the second method. That another set of premises is possible doesn't make fidelity to the one's adopted unsatisfactory.
  • Agent Smith
    9.5k


    Yep, math (Euclid) is axiomatized, to the extent possible. However, assuming a set of axioms in other areas flies against the principle (PSR) that all statements need to be proven (no flat assertions allowed).

    God exists! Don't you want to ask why?
  • Paine
    2k

    What does PSR refer to?
  • Agent Smith
    9.5k
    What does PSR refer to?Paine

    The principle of sufficient reason.
  • Paine
    2k

    Before anybody tries to prove anything with it, wasn't Leibniz saying that everything that exists must have some reason for being here because the thing that exists could easily not exist with another set of conditions?
  • Agent Smith
    9.5k
    becausePaine

    Si, si, señor!
  • 180 Proof
    14.1k
    :eyes: Neurath's Boat.
  • Agent Smith
    9.5k
    Neurath's Boat.180 Proof

    Ship of Theseus, only now we're making improvements + we're doing it while still sailing. :up: and yet I don't see anyone respond in a satisfying manner to Agrippa's challenge to the dogmatists.
  • Paine
    2k

    Does it not matter who is putting forth a dogma and what it is?
    It sounds like you want an unconditional boundary.
  • Agent Smith
    9.5k
    Nope, it doesn't matter who is doing anything unless ... you're ready to commit an ad hominem fallacy or arguing from authority and the like.

    I'm just exploring the possibility of escaping from the clutches of skepticism. Do you see a light at the end of this tunnel?
  • Paine
    2k
    Do you see a light at the end of this tunnel?Agent Smith

    Well, I do not share the ready optimism of Leibniz, but he did show that all alternatives do not need to be cancelled for something to be viable. The limits of negation apply to all. Which is sort of one of your points.
  • 180 Proof
    14.1k
    I'm just exploring the possibility of escaping from the clutches of skepticism.Agent Smith
    Pyrrhonian? Academic? Cartesian? Humean? ... Rortyan?
  • Kuro
    100
    Unlike logical circularity, which only makes for an unpersuasive argument (i.e. Q, thus Q) which is uninformative, epistemic circularity is actually necessary for any coherent epistemic principle.

    Suppose we have an epistemic principle, like evidentialism, saying that for any P we believe, we need to have evidence that P: if this thesis of evidentialism itself doesn't actually have evidence through evidentialism, then either evidentialism is self-refuting or is not of global-scope (e.g. there are exceptions to the rule). But our epistemic principles should be our most general and topic-neutral principles, so we're in a very problematic spot if we lack any global principles for good reasoning.

    But consider that, given evidentialism, it turns out we do actually have evidence of evidentialism for us to believe in evidentialism. This is clearly a case of epistemic circularity, but it is the only coherent route for us to take. It's not bad to have an epistemic circularity at all, in fact, we should be very worried if our epistemic principles failed to verify themselves!

    Note: I'm not saying evidentialism itself is true here: it's used as a prop for an example defending epistemic circularity. Evidentialism itself does not entail epistemic circularity, there are evidentialists who are foundationalists, infintitists or other non-coherentists
  • Kuro
    100
    principle (PSR) that all statements need to be proven (Agent Smith

    No! This is not correct, the PSR is not an epistemic principle regarding justification. The PSR is a metaphysical principle regarding explanation, that is, any facts in reality out there are explained by other facts (these can be causal explanations, grounding explanations, or what not).

    For instance, the fall of the apple is caused by, say, the properties of its mass, the laws of physics and what not, and these facts conjoined together explain the apple's falling.

    This is completely different from principles regarding epistemic justification. For instance, we may think we need a reason for all our beliefs, including us believing the apple fell, and perhaps our reason for thinking this is that we think our senses are reliable (reliabialism), we're using induction (Bayesianism), so on.

    The first is an explicitly metaphysical principle not about what we should believe & standards of justification but about the explicability of reality, the other are epistemic principles about our beliefs and justification

    By the way, the PSR is usually restricted to contingent facts. Proponents of the PSR do not generally think necessary facts, like 2+2=4 or the law of identity require further metaphysical explanation, but only contingent facts like eating dinner today, though not everyone restricts it, obviously
  • Paine
    2k

    Very interesting.
    Needing a reason for a reason not indicting all attempts toward those ends.
    (Your comment went well beyond that observation).
  • Banno
    23.3k
    Doesn't it seem odd to you that the trilemma lists three ways to prove something then concludes that proof is impossible?

    All three work.
  • Agent Smith
    9.5k
    Nice! In being circular with respect to justification, reason, sensu amplissimo is not a hypocrite (practices what it preaches) - it demands arguments and it itself is supported by one. Just curious, what is this argument reason employs to prove itself as the method for discovering truths?

    So the choices are: reason as a hypocrisy (it fails to self-justify) OR reason as a circularity (it self-justifies). Can we say that what we're dealing with here is a vicious virtuous cycle?

    Yes Agrippa's trilemma is self-refuting but only if you assume it to be true; but then the refutation would be self-refuting; this refutation of the refutation itself is also self-refuting; so on ad infinitum. The bottom line: once we assume Agrippa's trilemma, it precludes logic - no argument is permissible beyond that point and that means you can't refute Agrippa's trilemma. In fact this argument which I just made is also inadmissible and to complicate matters further even this one which I'm making is not to be taken seriously, so on and so on ... ad nauseum/ad infinitum. :zip:

    What are our options? We have to prove Agrippa's trilemma is unsound. One way is to say there's a 4th alternative i.e. Agrippa's trilemma is a false trichotomy. Any ideas what this 4th option is?

    Or we could follow Kuro's lead and say that the circularity isn't vicious but virtuous; at the very least, reason ain't no hypocrite (it demands of itself what it demands of others and ... meets those demands; how exactly, Kuro will tell us).
  • Kuro
    100
    OR reason as a circularity (it self-justifies). Can we say that what we're dealing with here is a vicious virtuous cycle?Agent Smith

    Or we could follow Kuro's lead and say that the circularity isn't vicious but virtuous; at the very least, reason ain't no hypocrite (it demands of itself what it demands of others and ... meets those demands; how exactly, Kuro will tell us).Agent Smith

    Excellent: exactly my point. :)
  • Agent Smith
    9.5k
    Merci, but where's the argument ... that proves/suggests reason is our go-to-person if our objective is to find the truth?
  • god must be atheist
    5.1k
    B. None of the three (1, 2, and 3) are satisfactory

    Ergo,

    C. Nothing can be proven
    Agent Smith

    Merci, but where's the argument ... that proves/suggests reason is our go-to-person if our objective is to find the truth?Agent Smith

    I think the error in Agrippa's theorem is in Point B. He said, "none of the three are satisfactory."

    The solution to the problem, or the refutation of the trilemma is ridiculously simple. Substitute B with B1, where B1 says "all three are satisfactory, any one of them individually and any two in combination or all three."
  • god must be atheist
    5.1k
    To say none of the three are satisfactory is an arbitrary, personal judgment. So is the sentence or claim "all three are satisfactory, any one of them individually and any two in combination or all three."

    This can't be decided by logic. This can only be decided by an arbitrary personal call which you hold true: B or B1.
  • Agent Smith
    9.5k


    1. Infinite regress
    2. Circularity
    3. Axiom

    3, according to Agrippa, unsatisfactory, options. Nevertheless, the skeptics did have beliefs. Therein lies the rub! Pragmatism?
  • god must be atheist
    5.1k
    3, according to Agrippa, unsatisfactory, options.Agent Smith

    So...according to Agrippa. His word against mine.
  • god must be atheist
    5.1k
    All three workBanno

    Sorry, I did not see this. You beat me to it.
  • Agent Smith
    9.5k
    So...according to Agrippa. His word against mine.god must be atheist

    Sophia (wisdom)?
  • god must be atheist
    5.1k
    A. there are only 3 possibilities

    1. Infinite regress (every premise requires an argument; every premise of that argument requires a separate argument; so on ad infinitum)

    2. Axiomatic arguments (assume a specific set of premises)

    3. Circularity (the argument's conclusion is just a restated premise)

    B. None of the three (1, 2, and 3) are satisfactory
    Agent Smith

    Doesn't it seem odd to you that the trilemma lists three ways to prove something then concludes that proof is impossible?

    All three work.
    Banno

    Agent Smith, you read more carefully, please.

    Agrippa called them three possibilities of proofs. PROOFS. So they are not just a walk-in-the-park, or dancing in the rain, or having a sandwitch at Mrs. Yashinski's tea party. They are PROOFS.

    There is no such thing as a proof that does not work. If it does not work, it is not a proof.

    Agrippa called them Proofs. So it is given already, that they work, and do the job.

    Then agrippa says it, quite inappropriately, that they are not satisfactory.

    How can he say that? When he had already agreed that they are satisfactory, when he called them proofs.

    There is no such thing as an unsatisfactory proof. In that case it's not a proof.

    So... Agrippa commits a self-contradiction.

    Seeing that is how you arrive at the truth.
  • god must be atheist
    5.1k
    Sophia (wisdom)?Agent Smith

    I don't know what you are talking about. You are saying I am stupid compared to Agrippa? If you read my one previous post, you will see that it's quite the other way around. It was HE who dug himself in a logical contradiction, not me.

    So... according to you Wisdom is to commit logical faults in arguments? (Rhetorical question. Just please don't assume I am stupider than any of the philosophers I criticize. I may or may not be, but just don't assume that. Aside from that insult, you are also committing an appeal to authority fallacy, when you say, "yes, GMBA, you seem to be right, but this other guy I quoted is wise, and you are not.")
  • god must be atheist
    5.1k
    To be fair, the kudos of wisdom go to Banno, not to me. My wisdom in this case lay merely in understanding plain sentences.
  • Agent Smith
    9.5k
    Agrippa, all he does is, ask the question whether reason meets its own standards. It all starts off with infinite regress really - if reason demands justification, that justification must be justified, and the justification of the justification must also be justified. This is unacceptable, one reason being the process is endless (we'll never be able to prove anything).

    What are our options?

    1. Axioms (assume truth), but remember this is exactly that which is being rejected by Agrippa reason. No flat assertions.

    2. Circularity, but that's a big no no in logic. Again, reason applied to reason. This is a flat assertion, there's no argument, but that's a different story.

    Thus the trilemma is established - it's got to be one od these 3 and nothing else and all 3 fall short of the mark, not because Agrippa says so but because reason says so.

    Summary: Reason says reason is no good,

    If there's a contradiction then it is this: Reason commits suicide - Agrippa has crafted a logical argument that logical argumentation fails. It's not Agrippa vs. Logic as you seem to be thinking, it's Logic vs. Logic. Kinda reminds me of the omnipotence paradox: if god defeats Himself, does He win or does He lose? Both? Neither?

    The SEP article on skepticism concludes: There are no justified beliefs.

    On an intuitive level, says a professor, how good is a system that self-destructs in such a fashion? Logic doesn't need enemies, it is its own worst enemy, oui monsieur?
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