Cartesian skepticism has been a hot topic lately at TSZ. I’ve been defending a version of it that I’ve summarized as follows:
Any knowledge claim based on the veridicality of our senses is illegitimate, because we can’t know that our senses are veridical.
This means that even things that seem obvious — that there is a computer monitor in front of me as I write this, for instance — aren’t certain. Besides not being certain, we can’t even claim to know them, and that remains true even when we use a standard of knowledge that allows for some uncertainty. (There’s more — a lot more — on this in earlier threads.)
In explaining to Kantian Naturalist why I am a Cartesian skeptic, I introduced the analogy of the Sentinel Islander:
KN,
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?
If we assume that our perceptions are veridical, we are making an equivalent mistake to the Sentinel Islander when he assumes that the VR goggles deliver veridical information about LaLa Land.
On the other hand, if we don’t know that our perceptions are veridical, and we can’t even judge the likelihood that they are veridical, then we are in no position to claim knowledge — justified true belief — regarding the external world.
This was KN’s initial objection:
My response:
If you can imagine it (as in the thought experiment), then it must be true.
However, if you merely experience it as part of ordinary life, it is very possibly false.
</sarcasm>
I think I’ll wait for Donnie’s twelfth concurrent OP defending this nonsense before responding again.
For those who aren’t counting and are wicked anxious to see it refuted for the 87th time, fear not. That’s only three more Donnie OP’s on this same subject.
For my criticism of the analogy, see here, and especially this bit:
I think that the Sentinel Islander thought-experiment only works as an analogy for perception if one adopts a picture of the senses that I think one should reject. Let’s call this the senses-as-instruments picture.
It is as if one is in a submarine, looking at electronic displays of information that purports to be correlated with features of the environment (depth, pressure, canyons, oceanic life, other vessels). One assumes that the instruments are working properly, and that the information being displayed accurately represents the real features of the environment.
In the case of the senses, of course, one cannot confirm that the senses are working properly without using them. There’s no method of confirming that they are functioning properly.In a submarine, or a car, one can detect malfunctioning sensor.
But the senses-as-instruments picture is badly mistaken. (For one thing, it leads to a homunculus fallacy, as we’ve noted before.)
The senses-as-instruments picture also presupposes mind-body dualism.
The senses as instrument picture requires that the cognitive agent be something different from the senses, in order for the senses to be instruments that the cognitive agent uses. But the senses are not detachable or separable from one’s own body. To see, to smell, to hear, to touch — all of these are modes of bodily activity. (Versions of this claim can be in Aristotle, Dewey, Merleau-Ponty, McDowell, Alva Noe, and Andy Clark.) To ‘instrumentalize’ the senses is to ‘instrumentalize’ the body, which means that the cognitive agency cannot be the body.
Conversely, if one recognizes that the senses just are us, in the mode of our being bodily open to the world, then one can recognize that we are essentially and necessarily embodied cognitive agents. To be embodied is to be sensually present and aware in our environments. Thus we can see that the analogy between our embodied sensual presence in the world and the VR headset in the Sentinel Islander thought-experiment does not work.
I would add that Descartes, in setting up skepticism about the external world in the First and Second Meditations, actually does covertly rely on an instrumental picture of the senses and thereby actually does presuppose mind-body dualism, even though the argument for mind-body dualism does not appear until the Sixth Meditation. That is but one of many vicious circularities in this supposed authoritative text of foundationalist epistemology.
walto,
This is my only “concurrent” OP on the topic, walto. The previous one was in February 2014.
But don’t let a little reality get in the way of your angry old man rants. They’re entertaining.
KN,
Nothing about my position presupposes mind-body dualism or leads to the homunculus fallacy.
Mind and perception are both bodily functions, and we don’t need to “re-perceive” the results of our perceptual processes.
All that’s needed for the analogy to work is that perception be a causal chain, and that the results of perception be available to consciousness.
In the Sentinel Islander scenario, it’s the VR headset that injects non-veridical information into the causal chain. For brain-in-vat scenarios, it’s the vat apparatus. For Cartesian demon scenarios, it’s the demon. And so on.
What is the difference between your computer monitor and the VR headset, and why do you believe your computer monitor is not giving you non-veridical information?
Perhaps you are being deceived by your monitor.
I do not know this. Am I the only one here who does not know this?
Take the following scenario:
I k you to close your eyes. I then tell you to pet the kitty, and you pet the kitty. But it wasn’t really a kitty, it was a skunk. But you believe it was a kitty.
Which if your senses was the source of the non-veridical information? Is it your sense of touch that failed you, or your sense of hearing?
You keep saying that you’re not claiming that our perceptions are not veridical. Bu I said pet the skunk and you heard pet the kitty. That you can’t know that you heard pet the kitty instead of pet the skunk sure seems to me to be calling into question your hearing.
From the other thread:
KN:
keiths:
KN:
No, I simply start with the accepted definition of knowledge as ‘justified true belief’ and observe that by that definition, we cannot attain knowledge with respect to the external world. Why? Because there are possible scenarios in which a) our senses, unbeknownst to us, are delivering false information about the world, and b) we have no way to circumvent our senses to get the information directly. It’s an observation of our limitations, not of God’s presumed abilities.
Not only is my conception of knowledge not theocentric, I’ve even argued that God himself, if he existed, couldn’t know that he wasn’t a brain-in-a-vat!
KN,
Only if the pragmatist is bad at reasoning.
Sure, p -> q can trivially be flipped around to get ~q -> ~p. That’s basic logic, and it has nothing to do with pragmatism per se. But it only leads to ~p if ~q is true.
Let’s do the substitution.
I perceive myself to be typing on a keyboard right now.
Let p be “I don’t know that I’m not a brain-in-a-vat”, and let q be “I don’t know that I’m typing on a keyboard right now.”
The skeptic notes that p -> q. That is, “If I don’t know that I’m not a BIV, I don’t know that I’m typing on a keyboard right now.” And since I don’t know that I’m not a BIV, I don’t know that I’m typing on a keyboard right now.
If you flip it around, it becomes ~q -> ~p. That is, “If I know that I’m typing on a keyboard right now, I know that I’m not a brain-in-a-vat.” That’s a valid logical move. The problem is that I don’t know that I am typing on a keyboard right now. All I know is that I seem to be typing on a keyboard. Without knowing it, I can’t assert ~q, so ~p doesn’t follow.
The error depends on being sloppy about what q stands for, conflating “I seem to be typing” with “I know I am typing.” If you’re careful about it, the fallacy is obvious.
Hahaha. I’m going to use that as a perfect example of begging the question in a class some day.
Exactly.
The problem, though, is that the skeptic can bring the same allegation against the realist. The stalemate is reiterated at the meta-level.
walto,
Exactly. In trying to substitute “I know I am typing” for “I seem to be typing”, you and KN are begging the question.
There’s no shortcut here. If you want to make a knowledge claim concerning X, you need to show that X is a justified true belief. Simply assuming what you’re trying to demonstrate won’t work.
How do you and KN get from “I seem to be typing” to “I know I am typing” — legitimately, this time?
Of course it is.
That’s not even relevant
keiths:
Neil:
Well, that settles it.
keiths:
Neil:
Well, that settles it.
It occurs to me that the keiths version of Cartesian Skepticism is self-refuting and the Sentinel Islander scenario is one long exercise in begging the question.
After all, it requires knowledge claims about the external world that no Cartesian Skeptic could be justified in making.
Be sure to claim you don’t actually know that you are teaching a class.
Hi, I’m a Cartesian Skeptic and I have just captured a Sentinel Islander for use in my VR scenario to show that I can’t possibly know that I have actually captured a real Sentinel Islander for use in my VR scenario, but that hardly matters because I don’t really need a real virtual reality headset either!
After all, we can’t possibly know that a real VR headset in the real world is not actually feeding us non-veridical information. So we’ll just pretend that we can know that a VR headset in the real world can deliver non-veridical information, even if we can’t know that we know this or how we could even possibly know it.
As a Cartesian Skeptic, that is.
If we cannot distinguish veridical information from non-veridical information, how do we know the VR headset is giving the Sentinel Islander non-veridical information unless we’re just assuming it?
And if we can know the VR headset is delivering non-veridical information, how can this be known, given that it is an object in the external world?
Quite so.
This is the implicit crypto-theism of keiths’s position: only God could be in a favored epistemic position relative to us (us = finite & embodied/embedded cognitive agents, however many different species there are in the Universe) analogous to the position that we are in relative to the Sentinel Islander in the thought-experiment. Just as we can look “sideways-on,” as it were, and see that the Islander is not perceiving the real world, so too it would have to be God who sees that we are not perceiving the real world.
The key difference between my atheism and keiths’s atheism could not be more profound. In keiths’s atheism, the epistemic position that theism assigns to God is simply unoccupied. In my version, there is no such epistemic position. (This might be construed, on a first pass, as the difference between the moderate atheism of Russell and Nagel with the far more radical atheism or post-theism of Marx and Nietzsche.)
In terms of the debates at TSZ, I’m staking out a position intermediate between keiths’s pseudo-pragmatism (because pragmatism has always, beginning with Peirce, defined itself in terms of the incoherence of the Cartesian description of cognitive agency) and Neil’s pragmatist instrumentalism. I think that Neil is right that keiths’s entire position indicates a crypto-theism, but I disagree with Neil that any version of metaphysical realism and a correspondence theory of truth must be crypto-theistic.
KN,
In my view, the truth of a claim is independent of whether a particular “epistemic position” exists or is occupied (unless, of course the claim is about epistemic positions and their occupancy).
That’s what I was getting at in this exchange:
KN:
keiths:
Would you agree that the islander’s knowledge claims are false even if no one is aware of that?
Suppose you are in an analogous position. A race of aliens envatted you some time ago, but they’ve since gone extinct. At this point no one, including you, is aware of the envatting.
I would say that it is true that you are envatted. Would you disagree?
KN,
I’m still interested in how you and walto get from “I seem to be typing” to “I know I am typing”, as needed for the modus tollens gambit.
keiths,
Because the difference between “I know I am typing” and “I seem to be typing” is just a difference in attitude or confidence towards the same content — the sentence “I am typing”. “I know I am typing” expresses very high confidence, and “I seem to be typing” expresses very low confidence. (I cannot imagine an actual use for either phrase. That’s revealing in itself.)
The high confidence is warranted — that is, high but still falling short of certainty — if I’ve done everything that’s reasonable to expect a human being to do in satisfying her epistemic responsibilities, and not if otherwise. (I shouldn’t say, “I know that’s a turtle!” when I see something at the bottom of the river where it’s murky and hard to make anything out, since it could very well be a rock.)
When it comes to the proposition (uttered in a here-and-now way), “I am typing,” there’s not enough slippage between the cognitive agent’s medley of proprioceptive, haptic, and visual sensations and her conceptualization of those sensations as I-am-in-a-typing situation. As embodied/embedded beings, it’s easier to fulfill our epistemic responsibilities with regard to perceptual judgments the closer we are in time and space to the situation that is judged in the perceptual judgment.
Denying the modus tollens “gambit” (aka the G. E. Moore shift) requires already committing oneself to a violation of ordinary language that could only be justified if skepticism itself were already vindicated, and therefore one cannot establish the vindication of skepticism by denying the Moorean shift from the outset. That’s why Walto said that your denial of the Moorean shift just begs the question, and he was right.
Put otherwise, see if you can come up with an ordinary language context, undistorted by any philosophical theorizing, in which “I seem to be typing (but I’m not sure)” would be a perfectly normal and appropriate thing to say.
My keyboard is connected to a computer rather than a typewriter, and I am conversing with someone whom I know to be a pedant on such things.
If he were a theist, he might agree.
KN,
No, it’s more complicated than that. “I seem to be typing” refers to the experience without necessarily asserting anything about the reality. “I know I am typing” refers to both the cognitive state and the reality.
Ditto for “I’m perceiving a cow in front of me” versus “I know there is a cow in front of me”. (Walto’s Bovine Exclusion Principle notwithstanding. I wonder if he would deny that these kids are benefitting from interacting with virtual dolphins and whales. Does the WBEP extend to cetaceans?)
You need the latter — “I know there is a cow in front of me” — in order to apply the “Moorean shift” successfully, but all you have is the former: “I’m perceiving a cow in front of me.” You can’t substitute the latter for the former without begging the question.
KN,
Don’t neglect the questions I pose in this comment.
And the whole thought experiment comes crashing down.
Now we find out that it doesn’t matter if no one knows that the goggles do not deliver veridical sensory information, that they are fostering an illusion, that LaLa Land doesn’t exist in the real world.
Assume your conclusion and it’s no surprise if that’s what you come to as a conclusion.
Here we come on a crucial point: I do regard perceiving as a kind of knowing, just because to perceive something is to perceive it as something, and thus as already involving the (non-inferentially elicited) use of concepts which are always intentional, and thus as ‘transcending’ whatever is (in the strict sense) merely sensed or felt.
Put more concisely, the line that you want to draw between knowing and perceiving is correctly drawn between perceiving and sensing.
keiths:
KN:
Even if you’re right, that isn’t the kind of knowledge you need to justify the substitution of “I know there is a cow in front of me” for “I’m perceiving a cow in front of me.”
They don’t mean the same thing, just as for the sickle cell patients, “I’m perceiving a whale in front of me” doesn’t mean “I know there’s a whale in front of me”.
Again, you need the latter — “I know there is a whale in front of me” — in order to apply the “Moorean shift” successfully, but all you have is the former: “I’m perceiving a whale in front of me.” You can’t substitute the latter for the former without begging the question.
keiths thinks it’s perfectly acceptable to conflate sense and perception, even if it contradicts his stated position that the senses are many and the perceptual apparatus is one.
Let’s not suppose this, for upon Karteithian Skepticism you cannot legitimately claim to know either.
So let us suppose that you suppose that you possess a really high-fi pair of virtual reality goggles, plus some sensitive motion sensors, but don’t really know that you do.
Now since VR goggles and motions sensors are things which exist in the external world, and given that a Karteithian Skepticism cannot claim to know anything about these items, one has to wonder why you have any reason at all to even suppose that you suppose that you posses these things.
Suppose you possess a set of blinders…
You cannot legitimately claim to know that you have kidnapped a North Sentinel Islander. That would require actual knowledge of the external real world which you claim you cannot legitimately have.
You cannot legitimately claim to know that this North Sentinel Islander which you think you have kidnapped knows nothing about virtual reality or computers. That would require actual knowledge of the external real world which you claim you cannot legitimately have.
You suppose you have kidnapped a North Sentinel Islander who you suppose knows nothing about virtual reality or computers (none of these actually exist, mind you – or if they do exist you cannot legitimately claim to know they exist), and you suppose that you tell him that the goggles and sensors are magical devices (none of these actually exist, mind you – or if they do exist you cannot legitimately claim to know they exist) that can grant him access to an actual land, LaLa Land, which is far away (a claim you cannot know is false).
Such nonsense.
Is there any philosopher in history who has taken skepticism seriously?
Lizzie must be laughing uproariously.
KN,
What an odd argument.
What qualifies a belief as knowledge is that it is justified and true, not that the claimant has done “everything that’s reasonable to expect a human being to do in satisfying her epistemic responsibilities.”
We’re not obligated to lie and say that the Sentinel Islander possesses knowledge about LaLa Land simply because he tried really hard, doing everything that it’s reasonable to expect someone to do in his situation.
Please stop trying to loosen the definition of knowledge (or justification, or truth). The failure to reach a desired, predetermined conclusion is not an excuse for relaxing definitions and lessening rigor.
The distinction here is ill-placed. For what is it for a belief to be justified?
Here’s one account: S is justified in believing think p just in case S would be able to offer reasons, grounds, or evidence for p if prompted to do so. (Typically the prompting comes from discursively articulated challenges — “why do you believe that?” — though it can also be self-directed — “why do I believe that?”.)
But in order to be able to offer reasons, grounds, or evidence for p if prompted to do so, S needs to be a favorable epistemic attitude towards p. She needs to have don everything that’s reasonable to expect a human being to do in satisfying her epistemic responsibilities.
So the satisfaction of epistemic responsibilities is quite crucial to the account of justification.
I think we should say that her beliefs about LaLa Land are indeed justified, but not true.
Nor is the need to reach a desired, predetermined conclusion an excuse for insisting that philosophy is as liner and precise as writing a computer program.
I mean, there are accounts of knowledge on which justification is a social practice and accounts on which it is not. Some epistemologists think that justification and truth are individually necessary and jointly sufficient conditions for knowledge; others worry about Gettier counterexamples. I have seen brilliant epistemologists argue that we should drop justification and identify knowledge with true belief, and I’ve seen other brilliant epistemologists argue that we should drop truth and identify knowledge with justified belief. Many philosophers who work in theories of truth argue that we should treat truth as a semantic notion, and there are competing accounts along those lines.
Point is, there are complexities here that can’t be waved aside just because one prefers simplicity and linearity.
Sure. Skepticism has a long and honorable history in both Western and Eastern philosophy, from antiquity to the present.
In antiquity, there was both the Pyrrhonian and Academic schools of Skepticism. The former is best known to us through the work of Sextus Empiricus, and the latter through Cicero.
Academic skepticism was revived in the 16h and 17th centuries, and perhaps the finest example of renaissance skepticism is Descartes’s older contemporary, Michel de Montaigne (who also invented and perfected the essay as a literary genre). Skepticism continues as a major intellectual force throughout the modern period, especially in crucially important philosophers like Pierre Bayle and David Hume. (Two recent articles on Bayle can be found here and here.)
In the past few years, we’ve had Robert Fogelin defend Pyrrhonian skepticism (see here), Peter Unger also defending skepticism, Barry Stroud writing on the significance of skepticism, and Stanley Cavell writing on what is skepticism reveals about the human condition. (here is a collection of articles I just found.) And we’ve also seen Michael Williams and Jay Rosenberg writing against Cartesian skepticism, largely by using Sellars.
Epistemology has, for better and for worse, defined itself in relation to skepticism — either for it or against it. It’s definitely important!
Good point, virtual reality presupposes a non virtual external reality capable of creating virtual reality
newton,
There has to be reality at some level, but virtual realities can be nested.
For instance, you could be a brain in a vat inside a simulation inside another simulation running on a real computer.
Simulations all the way down.
I’d be interested in how one could conceptualize the difference between a simulation and something like string theory.
Is it possible to have a simulation in which there is no “real” substrate?
Our poor Sentinel Islander. In the world of Cartesian Skepticism, there’s no justification for any claim to know that she actually exists. Talk about a license for abusing women.
Which is why men who abuse their wife and claim to have been operating under the belief that they were in a virtual reality world don’t get a pass, they were still abusing a woman.
God forbid the poor Sentinel Islander is a child. Talk about a license for abusing children.
Which is why men who abuse children and claim to have been operating under the belief that they were in a virtual reality world don’t get a pass, they were still abusing a child.
The entire world appears to operate as if Cartesian Skepticism is either false or is no excuse.
Perhaps keiths will claim that he thought he was making love to a rock and that the rock was welcoming his advances. But why does it matte to him what his defense consists of, since the prosecutor, judge, and jury all exist in the external world outside his mind and he cannot therefore justify and claim to know anything at all about them. Courts are for loons!
Since keiths cannot legitimately claim to know that KN, walto, Mung, or his own dear mother exist, who the hell is he trying to convince?
Thinking About Knowing came in today.
keiths is absent.
Perhaps he is searching for the real world.
KN:
keiths:
KN:
They have to be good reasons, grounds, evidence, or arguments.
No, because justification isn’t relative to the claimant’s capabilities. Suppose she does everything in her power, yet still can’t justify the belief. In that case the belief remains unjustified, despite her exertions.
On the other hand, suppose she easily justifies the belief with only a tiny bit of effort. In that case the belief is justified despite the fact that she didn’t do “everything that’s reasonable to expect a human being to do in satisfying her epistemic responsibilities.”
What matters is whether the justification succeeds, not whether the claimant has done all she reasonably can.
Consider two people, Almuerzo and Borodin. Almuerzo walked through town this morning and saw a ‘For Sale’ sign in the yard of the stately Victorian at the corner of Jackson and Elm. Borodin, who has been in solitary confinement for years, remembers that Victorian and often asks about it. The guards never answer, even when bribes are offered, and Borodin has no other source of information about the outside world.
Almuerzo justifiably believes that the house is for sale. If Borodin believes likewise, the belief is not justified, even though Borodin has done everything that a human could reasonably do in that situation.
Again, justification is not relative to an agent’s capabilities.
Perhaps the person providing the VR headsets to the Sentinal Islander was merely dreaming.
Perhaps the person providing the VR headsets to the Sentinal Islander was himself in a VR “reality.”