Cartesian Skepticism

The main features of Cartesianism are:

(1) the use of methodical doubt as a tool for testing beliefs and reaching certainty.

– A Companion to Epistemology, p 57

It seems odd to me that keiths, who denies the possibility of certainty, is a champion of Cartesian skepticism.

A Cartesian skeptic will argue that no empirical proposition about anything other than one’s own mind and its contents is sufficiently warranted because there are always legitimate grounds for doubting it.

… A Cartesian requires certainty.

– A Companion to Epistemology, p 457

keiths is not a Cartesian Skeptic.

Cartesian scepticism, more impressed with Descartes’ argument for scepticism than his own reply, holds that we do not have any knowledge of any empirical proposition about anything beyond the contents of our own minds. The reason, roughly put, is that there is a legitimate doubt about all such propositions because there is no way to justifiably deny that our senses are being stimulated by some cause (an evil spirit, for example) which is radically different from the objects which we normally think affect our senses.

A Companion to Epistemology, p 457

keiths is not a Cartesian Skeptic.

Is it even possible to be Cartesian Skeptic?

169 thoughts on “Cartesian Skepticism

  1. For anyone who (unlike Mung) actually wants to understand my skeptical position, there’s a long discussion of it on the Elon Musk thread, starting around here.

  2. keiths chooses to not declare his “skeptical position.” Sad, really. He adopts Cartesian Skepticism or he does not. He accuses KN of being a Cartesian Skeptic.

  3. I’m not sure I grasp the distinction between Cartesian skepticism as laid out here, and solipsism. Is there any?

  4. Cross-posting this from the Musk thread:

    Mung,

    It’s not a lie if it’s true.

    The main features of Cartesianism are:

    (1) the use of methodical doubt as a tool for testing beliefs and reaching certainty.

    I’m a Cartesian skeptic, not a Cartesian. Walto makes a similar mistake, conflating Cartesian skepticism with Cartesianism and “Cartesian theaterism”.

    Descartes appeals to certainty (of the cogito) in an attempt to escape skepticism. It’s an anti-skeptical move. I don’t follow his lead, because I am a Cartesian skeptic, not a Cartesian.

    You even provided a quote (in your new OP) that makes my point for me:

    Cartesian scepticism, more impressed with Descartes’ argument for scepticism than his own reply, holds that we do not have any knowledge of any empirical proposition about anything beyond the contents of our own minds.

    [Emphasis added]

    Why not learn about this stuff first instead of starting new threads that showcase your ignorance?

  5. I myself don’t see how one could be entitled to attribute more reliability to introspection than to exteroception, unless it is the perfectly trivial truth that one cannot apply the is/seems distinction to “seems”.

  6. Flint,

    I’m not sure I grasp the distinction between Cartesian skepticism as laid out here, and solipsism. Is there any?

    There’s more than one type of solipsism.

    Cartesian skepticism is quite distinct from ontological solipsism, which holds that nothing but the self actually exists.

    Epistemological solipsism — the idea that knowledge is limited to (some of) the contents of our own minds — is the closest to Cartesian skepticism, depending on the exact formulation.

    I use “Cartesian skepticism” to avoid the ambiguities of “solipsism”.

  7. keiths: I’m a Cartesian skeptic, not a Cartesian

    I never said that you were a Cartesian. I denied that you are a Cartesian Skeptic. You claim to be a Cartesian Skeptic, but you are not a Cartesian Skeptic.

    keiths:

    Why not learn about this stuff first instead of starting new threads that showcase your ignorance?

    I consulted a number of different sources, all of which which indicate that you don’t understand Cartesian Skepticism.

  8. KN,

    I myself don’t see how one could be entitled to attribute more reliability to introspection than to exteroception, unless it is the perfectly trivial truth that one cannot apply the is/seems distinction to “seems”.

    “There is a cow in front of me” is much easier to doubt than “I feel pain,” spoken honestly. It’s harder (though not impossible) to see how the latter could be mistaken.

  9. Mung,

    I never said that you were a Cartesian. I denied that you are a Cartesian Skeptic.

    And you based it upon this:

    The main features of Cartesianism are:

    (1) the use of methodical doubt as a tool for testing beliefs and reaching certainty.

    – A Companion to Epistemology, p 57

    [emphasis added by keiths]

    You wrote:

    It seems odd to me that keiths, who denies the possibility of certainty, is a champion of Cartesian skepticism.

    [my emphasis]

    You confused Cartesianism with Cartesian skepticism, and of course you are now denying your mistake.

    Typical value-subtracting Munginess.

  10. Mung: keiths chooses to not declare his “skeptical position.” Sad, really.

    Trumpesque.

  11. Flint:
    I’m not sure I grasp the distinction between Cartesian skepticism as laid out here, and solipsism. Is there any?

    Doesn’t appear to be. Perhaps we should ask a Cartesian skeptic if we can find one.

  12. Remember that time some guy created a thread to try to determine Mung’s actual position on ID and how Mung got all huffy and refused to take part?

    Yeah, me neither.

  13. Alan,

    Perhaps we should ask a Cartesian skeptic if we can find one.

    It can be hard to recognize Cartesian skeptics when you don’t know what Cartesian skepticism is. Such a simple concept, too.

    Perhaps you should consult someone who is less confused than you. Should be easy to find.

  14. keiths:
    Alan,

    It can be hard to recognize Cartesian skeptics when you don’t know what Cartesian skepticism is.Such a simple concept, too.

    Perhaps you should consult someone who is less confused than you.Should be easy to find.

    Simple, yes. Trite, even. Consequences, none.

  15. keiths,

    My position is perhaps the same as yours. But I don’t care whether or not I’m a Keithian skeptic. And I don’t care whether or not I’m a Cartesian skeptic. If you want people to understand your views, and people don’t agree on the meaning of your categorization of them, then why argue about the category? Are you a philosopher? Do you claim expertise on Descartes’ epistemology? Do you feel compelled to set philosophers straight on Descartes?

    Why dignify this attempt by Mung, who turns into piss when in danger of being pinned down on substantive points, to make a big deal of pinning you down on a trivial matter of nomenclature?

  16. Mung,

    Every eleventh word out of your mouth is hypocrite. As I just said to keiths, you turn to piss when in danger of being pinned down on substantive points. You’re presently engaged in the most disgusting of evasion in another thread. And what do you do, but highlight an attempt to pin keiths down on a trivial point?

    What you’re doing is hypocritical in the extreme. This gotcha-gotcha bit of yours will be hypocritical until you start working for resolution of some points, instead of disappearing or changing the topic or tossing off taunts when things are not going your way.

  17. petrushka,

    From Section 1.2 of the SEP article I just linked to:

    Independent of this theory of ideas, Descartes’ methodical doubts underwrite an assumption with similar force: for almost the entirety of the Meditations, his meditator-spokesperson — hereafter referred to as the ‘meditator’ — adopts the methodological assumption that all his thoughts and experiences are occurring in a dream. This assumption is tantamount to requiring that justification come in the form of ideas.

    According to Wikipedia, there is a distinction between the methodological skepticism of Descartes and philosophical skepticism. The article on philosophical skepticism links the term “methodological skepticism” to the article on Cartesian doubt.

    I think that my skepticism would be better described as philosophical than as methodological. I’m not blundering into an argument with keiths as to whether philosophical skepticism is a better fit for his views. If it were, though, I’d love to see him show Mung how to concede a point gracefully.

  18. keiths: “There is a cow in front of me” is much easier to doubt than “I feel pain,” spoken honestly. It’s harder (though not impossible) to see how the latter could be mistaken.

    There’s an important difference here, though. Feeling a pain is not an intentional act. There’s nothing that the pain is about. It’s a mere having-of-the-pain. Compare that to a memory — there’s something that the memory is about. It has an intentional object, though one disclosed through introspection. Perceiving the cow — or any physical object — is intentional and exteroceptive.

    The reason why there’s no room for doubt in the case of feeling-pain is not because introspection is more reliable than exteroception, but because there’s no room for skeptical worries when there’s no intentional structure to the cognitive act.

    When there’s intentional structure, Cartesian skepticism can get a foothold (“I thought I remembered being here before, but now I’m not sure if I really do?”), regardless of whether our access to the intentional structure is introspective (e.g. memories) or exteroceptive (e.g. perceptions).

  19. Kantian Naturalist: The reason why there’s no room for doubt in the case of feeling-pain is not because introspection is more reliable than exteroception,

    I would say it is tautological.

    What is the “I” that feels pain? Are we talking about an homunculus?

  20. petrushka: What is the “I” that feels pain? Are we talking about an homunculus?

    I would say that it’s the living body itself which feels pain, not something else that is somehow inside the body or attached to it.

  21. How is “we” or “I” different from the body.

    What is the value added by nomenclature?

    Seriously, I see nothing added by technical terms and verbosity. The colloquial meaning of I hurt or I’m hungry is clear enough.

    If you start analyzing such statements from a medical science point of view, you may discover that “I’m hungry” is in some cases not correlated with the need for calories, and that pain may not refer to an injured body part.

  22. OMagain:

    Remember that time some guy created a thread to try to determine Mung’s actual position on ID and how Mung got all huffy and refused to take part?

    Yeah, me neither.

    The thread that OMagain is not referring to ( 🙂 ) is here:

    Why Mung is an ID supporter

    It puts Mung into full squirm mode.

  23. KN,

    There’s an important difference here, though. Feeling a pain is not an intentional act. There’s nothing that the pain is about. It’s a mere having-of-the-pain…

    The reason why there’s no room for doubt in the case of feeling-pain is not because introspection is more reliable than exteroception, but because there’s no room for skeptical worries when there’s no intentional structure to the cognitive act.

    I’m not talking about feeling pain — I’m talking about having a thought or making a statement about feeling pain. My phrasing was quite deliberate:

    “There is a cow in front of me” is much easier to doubt than “I feel pain,” spoken honestly.

  24. keiths:

    It can be hard to recognize Cartesian skeptics when you don’t know what Cartesian skepticism is. Such a simple concept, too.

    Alan:

    Simple, yes. Trite, even. Consequences, none.

    In your case there seem to be no consequences other than annoyance. You dismiss what you don’t understand.

    For someone who’s less incurious about the world, and who likes to think about the nature of reality, the consequences are quite real.

  25. Tom,

    My position is perhaps the same as yours. But I don’t care whether or not I’m a Keithian skeptic. And I don’t care whether or not I’m a Cartesian skeptic. If you want people to understand your views, and people don’t agree on the meaning of your categorization of them, then why argue about the category?

    Because the category, and the label applied to it, mean something. Why do people sometimes specify that they are talking about Newtonian physics? Because they’re drawing a meaningful distinction.

    Why dignify this attempt by Mung, who turns into piss when in danger of being pinned down on substantive points, to make a big deal of pinning you down on a trivial matter of nomenclature?

    I didn’t dignify it. I showed that he doesn’t know what he’s talking about.

  26. keiths:
    keiths:

    Alan:

    In your case there seem to be no consequences other than annoyance.You dismiss what you don’t understand.

    For someone who’s less incurious about the world, and who likes to think about the nature of reality, the consequences are quite real.

    And…
    What are they?

  27. Tom,

    According to Wikipedia, there is a distinction between the methodological skepticism of Descartes and philosophical skepticism.

    It’s unwise to base your understanding on a single line in a Wikipedia article that can be edited by anyone — particularly when that article contradicts a second Wikipedia article that you also cite!

    I think that my skepticism would be better described as philosophical than as methodological. I’m not blundering into an argument with keiths as to whether philosophical skepticism is a better fit for his views.

    Methodological skepticism is a subset of philosophical skepticism, and both are categories. I call myself a Cartesian skeptic because that label is more specific, and therefore more informative, than either of the others.

  28. Alan,

    Here are two of the biggies:

    1. The realization that the veridicality of our senses is an assumption we’re making, not something that can actually be demonstrated.

    2. The realization that the real world might therefore be nothing like what we take it to be.

  29. keiths: 2. The realization that the real world might therefore be nothing like what we take it to be.

    The world as described by physics is not much like what we see or understand through our senses.

    The question I find interesting is to what extent such discrepancies between common sense and science do or should influence the conduct of our lives.

  30. keiths:
    Alan,

    Here are two of the biggies:

    1. The realization that the veridicality of our senses is an assumption we’re making, not something that can actually be demonstrated.

    Firstly, this still seems to be losing the question in terms of foundationalism, just answering it in the negative.

    Secondly, it’s not clear if “demonstrated” means something quite weak, like “have good reasons for accepting” or something quite strong like “established as certain by deductively valid argument”.

    When Descartes thought that the existence of God and the immortality of the soul could be demonstrated, he was using “demonstration” in the second sense. As was Hume when he denied thst the principle of causation could be demonstrated.

    2. The realization that the real world might therefore be nothing like what we take it to be.

    Still not clear how this logical possibility is supposed to affect inquiry and science.

  31. Kantian Naturalist: Firstly, this still seems to be losing the question in terms of foundationalism, just answering it in the negative.

    Sorry, that should have been “framing the question” — not sure what the autocorrect on my phone did there.

  32. keiths: Here are two of the biggies:

    1. The realization that the veridicality of our senses is an assumption we’re making, not something that can actually be demonstrated.

    2. The realization that the real world might therefore be nothing like what we take it to be.

    1: I do not make such an assumption. I’m doubtful that it is a meaningful assumption.

    2: I’ve been saying for some time, that we should not talk about “what the world is like”. The closest we can hope to come is “how we perceive the world.”

  33. petrushka,

    The world as described by physics is not much like what we see or understand through our senses.

    The scientific image is just as dependent on the senses as the manifest image. Every scientific observation we make, every measurement, every experimental result, enters our minds via the senses.

    Cartesian skepticism casts doubt on both the manifest and scientific images.

  34. keiths:

    1. The realization that the veridicality of our senses is an assumption we’re making, not something that can actually be demonstrated.

    KN:

    Firstly, this still seems to be [framing] the question in terms of foundationalism, just answering it in the negative.

    You don’t have to be a foundationalist to see the problem. My Sentinel Islander scenario shows that.

    Secondly, it’s not clear if “demonstrated” means something quite weak, like “have good reasons for accepting” or something quite strong like “established as certain by deductively valid argument”.

    For the purposes of this discussion, we’re talking about whether we know that our senses are generally veridical. The demonstration needs to be strong enough to justify a knowledge claim, but it can’t be.

    keiths:

    2. The realization that the real world might therefore be nothing like what we take it to be.

    KN:

    Still not clear how this logical possibility is supposed to affect inquiry and science.

    How it affects philosophical inquiry should be obvious: it upends epistemology, showing that we cannot legitimately claim knowledge of the external world, including via science.

    Otherwise, it doesn’t change the way science operates. Why would it?

  35. KN,

    The lingering question from the other thread is this:

    Your reasoning, when applied to the Sentinel Islander scenario, generates a false conclusion. The problem is obvious: your logic is unsound and circular.

    I wrote:

    Here’s an analogy that shows how serious the problem of circularity is for your position.

    Suppose that a few decades from now you possess a really high-fi pair of virtual reality goggles, plus some sensitive motion sensors. You kidnap a North Sentinel Islander who knows nothing about virtual reality or computers, and you tell him that the goggles and sensors are magical devices that can grant him access to an actual land, LaLa Land, which is far away.

    The islander learns to navigate LaLa Land successfully, even carrying out tasks within it. If you ask him questions about LaLa Land, he answers them “correctly”. He even claims to know things about LaLa Land, which he takes to be real. We know better, because we understand that the goggles do not deliver veridical sensory information. They are fostering an illusion. LaLa Land doesn’t exist in the real world.

    The islander could argue, KN-style:

    1. I assume that the goggles deliver veridical information about LaLa Land.

    2. On the basis of that assumption, I am able to navigate LaLa Land successfully and satisfy my goals.

    3. Therefore, the goggles deliver veridical information about LaLa Land.

    Is he right? Obviously not. We can see that he is being fooled, and we can diagnose the problem with his argument: it’s blatantly circular.

    How is your argument any better than his?

    Your logic is broken. Why do you, a professional philosopher, insist on applying bad reasoning to the question of Cartesian skepticism?

    Why do you prefer a bad argument against Cartesian skepticism to a good argument for it?

  36. keiths:

    [Keiths’s response to “what are the consequences of keithian skepticism]

    1. The realization that the veridicality of our senses is an assumption we’re making, not something that can actually be demonstrated.

    Yet pragmatically, if we assume that our sensorimotor interactions with the world external to our inner awareness are reliable to the extent they are, we make real progress in understanding. We observe, measure, perform controlled experiments, record and share information.

    Seems to me, we can bear in mind we may be being deceived or whatever else it is we are supposed to realise, and it makes not one jot of difference. We can still be insatiably curious about our surroundings without needing to worry about whether our perception is flawed or inaccurate. And we can compare notes and improve that perception with scientific instruments.

    2. The realization that the real world might therefore be nothing like what we take it to be.

    And what do you do with this possible realisation other than continue to explore reality? It does not limit such efforts to establish what reality might be hiding from us. I think you have suggested that not treating your keithian skepticism seriously is the same as being incurious about the external world. You have so far failed to demonstrate any such link.

  37. keiths: How it affects philosophical inquiry should be obvious: it upends epistemology, showing that we cannot legitimately claim knowledge of the external world, including via science.

    Your argument looks to be something like this: all assertions about the world are justified by the assertion that the senses are veridical. But the assertion that the senses are veridical cannot itself be justified. Therefore none of our assertions about the world are justified.

    That argument undoes epistemology only if one is assuming very strong claims about the structure of justification. For one thing, it assumes that coherentism is false. Do you have an argument against coherentism? Or is it just “obvious” (to you) that coherentism is false? For another, it assumes “infallibilism” about knowledge: that justification strictly implies truth (if X is justified, then X is true).

    This goes to the Sentinel Islander thought-experiment. By my lights, the Islander is perfectly justified in his reasoning, although it is false. Justification does not strictly imply truth. At most justification is a reliable indicator of truth, but not a perfect one. But it needs to be shown how justification and truth actually come apart in practice. Since there’s no one who stands in relation to us as we would stand in relation to the Islander, there’s no possibility of justification and truth coming apart for us in a systematic or global way. There’s only the possibility of justification and truth coming apart in particular local contexts. But that’s exactly what fallibilists about knowledge have always maintained.

    Otherwise, it doesn’t change the way science operates. Why would it?

    If we can upend epistemology without affecting science in any way, that strikes me as a fatal problem with how we’re doing epistemology in the first place.

  38. Alan Fox: Yet pragmatically, if we assume that our sensorimotor interactions with the world external to our inner awareness are reliable to the extent they are, we make real progress in understanding. We observe, measure, perform controlled experiments, record and share information.

    Exactly. And our progress in doing so gives us every reason to believe that our sensorimotor interactions with the world are generally reliable. The logical possibility that they aren’t does nothing to further the process of inquiry.

    Seems to me, we can bear in mind we may be being deceived or whatever else it is we are supposed to realise, and it makes not one jot of difference. We can still be insatiably curious about our surroundings without needing to worry about whether our perception is flawed or inaccurate. And we can compare notes and improve that perception with scientific instruments.

    Yes.

    And what do you do with this possible realisation other than continue to explore reality? It does not limit such efforts to establish what reality might be hiding from us. I think you have suggested that not treating your keithian skepticism seriously is the same as being incurious about the external world. You have so far failed to demonstrate any such link.

    Indeed. I don’t even see how keiths’s version of “Cartesian skepticism” is consistent with distinguishing between science and ideology, fact from fiction, knowledge from myth. It looks like a retreat from everything that actually matters in human life for the sake of mere logical possibility. That’s why it relies on a covertly theocentric conception of knowledge.

    By contrast, if we begin with the anthropocentric conception of knowledge inaugurated by Kant, and then naturalize that conception along the lines already developed by pragmatists, we get an epistemological method consisting of systematic reflection on our actual epistemic practices and their biological basis (what Dewey calls “the biological matrix of inquiry”). I think that philosophy ought to matter to us, and that it ought not be mental masturbation. Philosophy that is not the service of “how should I live?” is not worth doing.

  39. On the “Slavery in the Bible” thread, after walto recycles his “har, har, you don’t know your own name” pseudo-refutation, petrushka asks:

    What is this name thing? It sounds like an incantation, magic. People call us by various names. I’ve had friends and classmates call me by a dozen different (printable) names. I don’t “have” a name.

    There are names I recognize when someone calls me. Oddly enough I recognized those dozen or so the first time I heard them.

    The point is that unless we know that our perceptions are generally veridical, we don’t actually know that people are calling us by certain names.

    As I explained to KN:

    keiths:

    The fact that the universe is 13.7 billion years old is objective knowledge, and it remains so regardless of “human and animal needs, interests, and desires.”

    KN:

    That’s pretty funny, coming from someone who insists that such “objective knowledge” is also “illegitimate”.

    keiths:

    It’s knowledge with the implicit asterisk, KN.

    We can’t know that the universe is 13.7 billion years old without knowing that our senses are generally veridical. If we did know the latter, we could also know the former. Hence the asterisk.

    Do you still not get that?

  40. That was a very long admission that you don’t know your own name, jim. Amazing that you’re so sure of everything else!

  41. walto,

    Now if only you could admit that you lack the skills to refute my position.

    A self-styled “philosopher” who can’t even refute a position he describes as “borderline nuts”.

  42. keiths,

    ‘Your position’ is nothing new, jimmy. It’s an old hat whack view that nobody can know anything unless they know antecedently that their method of obtaining knowledge is reliable. As i’ve said many times it’s inconsistent with what nearly everyone but you means by ‘know,’ but is not ‘refutable.’ It doesn’t need to be refuted anymore than the claim that Napoleon’s ghost used to be living in Patrick, but has now moved to Australia.

    I’ve explained this to you numerous times now, bobbie. However, you seem as incapable of learning it as you are of knowing your own name.

    But again, you DO think you know every other fucking thing under the sun somehow. Your self-proclaimed ignorance of everything hasn’t been accompanied by an iota of modesty. Very weird, Leonard. And evidence that, when you’re not posting about your silly ‘skepticism,’ you use ‘know’ just as everybody else does–in a way completely inconsistent with your half-baked attempts at philosophy.

  43. Alan,

    Yet pragmatically, if we assume that our sensorimotor interactions with the world external to our inner awareness are reliable to the extent they are…

    We don’t have to make that assumption. We have the option of being honest with ourselves instead.

    …we make real progress in understanding. We observe, measure, perform controlled experiments, record and share information.

    But we still can’t claim knowledge of the external world, because we don’t know that our perceptions are veridical. Again, why not be honest about that?

    Seems to me, we can bear in mind we may be being deceived or whatever else it is we are supposed to realise, and it makes not one jot of difference.

    It does make a difference. Even you should be able to see the difference between

    The real world might bear no resemblance to how we perceive it.

    …and…

    We can perceive the world pretty much as it really is.

    Alan:

    We can still be insatiably curious about our surroundings without needing to worry about whether our perception is flawed or inaccurate.

    Why draw the line there? Why not be insatiably curious about everything including the fact that our perceptions might not be accurate?

    You tend to dismiss things that you don’t understand, but that’s a self-defeating strategy. You should be more curious, not less, about the things that baffle or discomfit you.

    And what do you do with this possible realisation other than continue to explore reality?

    You continue to explore what your senses are telling you without assuming that they accurately represent reality.

    It’s a simple matter of intellectual honesty. Continue to do what you can, but don’t claim to know what you cannot know.

    Compare that with what KN is doing: he wants to sweep it under the rug and lie to himself, all the while using unsound logic that has been shown to yield false conclusions. It’s the antithesis of intellectual honesty.

  44. walto,

    But again, you DO think you know every other fucking thing under the sun somehow.

    No, and of course I”ve never claimed to. That’s just your insecurity talking.

    Your self-proclaimed ignorance of everything hasn’t been accompanied by an iota of modesty.

    I certainly won’t claim to be wrong about something just to soothe your fragile ego, walto.

    And evidence that, when you’re not posting about your silly ‘skepticism,’ you use ‘know’ just as everybody else does–in a way completely inconsistent with your half-baked attempts at philosophy

    No, it’s consistent with what I’ve been saying all along and with what I just wrote to KN:

    It’s knowledge with the implicit asterisk, KN.

    We can’t know that the universe is 13.7 billion years old without knowing that our senses are generally veridical. If we did know the latter, we could also know the former. Hence the asterisk.

    Do you still not get that?

    Do you still not get that, walto?

  45. Your ‘implicit asterisk’ is nonsense. Sorry, Ralphy. We’ve caught on that you use an asterisk because you can neither state nor even contemplate exactly what it’s supposed to represent. In fact, it’s among the stupider components in what is a highly ridiculous position.

    And that’s saying something, Shirl!

  46. You never seem to tire of repeating that claim, walto, no matter how often it’s refuted.

    Here’s one of the latest refutations:

    walto,

    No. Only YOU talk about your absurd endless propositions, that can’t even be stated.

    My Cartesian skepticism can easily be stated, and it doesn’t require “absurd endless propositions”. It could be stated this way, for instance:

    Any knowledge claim based on the veridicality of our senses is illegitimate, because we can’t know that our senses are veridical.

    The “absurd endless” disjunction you’re complaining about was introduced by KN as a way of itemizing the different ways in which our senses could fail to be veridical.

    Your objection to that is silly. We make statements all the time that, if expanded, would produce massive or even infinite disjunctions. For example, someone might say “I’m going to meet Heidi for lunch on Wednesday, unless she can’t make it.” Expanded, that might read something like this: “I’m going to meet Heidi for lunch on Wednesday unless a) her boss asks her to work through lunch, or b) there’s a major earthquake, or c) Jesus returns in a blaze of glory, or d) she’s sick that day, or e) a meteor hits her, or…

    This stuff isn’t that hard, walto, if you’d just apply some discipline to your thinking.

  47. KN,

    Your argument looks to be something like this: all assertions about the world are justified by the assertion that the senses are veridical. But the assertion that the senses are veridical cannot itself be justified. Therefore none of our assertions about the world are justified.

    That argument undoes epistemology only if one is assuming very strong claims about the structure of justification. For one thing, it assumes that coherentism is false. Do you have an argument against coherentism? Or is it just “obvious” (to you) that coherentism is false? For another, it assumes “infallibilism” about knowledge: that justification strictly implies truth (if X is justified, then X is true).

    This goes to the Sentinel Islander thought-experiment. By my lights, the Islander is perfectly justified in his reasoning, although it is false. Justification does not strictly imply truth.

    We’re talking about knowledge, KN. Justified true belief. The islander’s belief is false. It’s not knowledge.

    When he claims to know things about LaLa Land, which he regards as an actual place, he is wrong. He uses your logic to reach a false conclusion. It’s bad reasoning..

    Since there’s no one who stands in relation to us as we would stand in relation to the Islander, there’s no possibility of justification and truth coming apart for us in a systematic or global way.

    As I’ve already explained at least twice, a falsehood remains false even if no one knows that it’s false:

    You wrote:

    The problem with the Sentinel Islander scenario is that there isn’t anyone who actually occupies an epistemic position compared to us that we would have relative to the Islander.

    keiths:

    Sure there is. In the Cartesian demon scenario, it’s the demon. In the brain-in-vat scenario, it’s the designers of the vat apparatus.

    Either way, it doesn’t matter. An error is still an error even if no one is aware of it.

    Suppose that everyone on earth dies in a viral epidemic, except for the Sentinelese. An islander stumbles upon a goggle/sensor set and learns to operate it. He comes to believe that LaLa Land is real, and he claims to know things about it.

    No one on earth knows that he is wrong. Does that make him right? Of course not.

    KN:

    Since that epistemic position is unoccupied, what we’re left with is a mere logical possibility.

    keiths:

    As noted above, it makes no difference whether that epistemic position is occupied.

    .

  48. KN:

    Still not clear how this logical possibility is supposed to affect inquiry and science.

    keiths:

    How it affects philosophical inquiry should be obvious: it upends epistemology, showing that we cannot legitimately claim knowledge of the external world, including via science.

    Otherwise, it doesn’t change the way science operates. Why would it?

    If we can upend epistemology without affecting science in any way, that strikes me as a fatal problem with how we’re doing epistemology in the first place.

    It does affect science, and I just explained how:

    it upends epistemology, showing that we cannot legitimately claim knowledge of the external world, including via science.

    Good grief, KN.

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