I note briefly in the video that a further important challenge to explanationism is that many philosophers reject inference to the best explanation in general. For more on this, most of the videos in my scientific realism series touch on the debate concerning IBE in science. I also discuss critiques of IBE and outline alternative approaches to epistemology in these videos: How to be an empiricist - ua-cam.com/video/TSYKP6UKpwk/v-deo.html Induction without rules - ua-cam.com/video/DY0-tRu0ms0/v-deo.html Voluntarist epistemology - ua-cam.com/video/jHnx7ddV3fA/v-deo.html My videos on laws of nature, mentioned at 34:08: ua-cam.com/video/q4gjiVAQ3r0/v-deo.html ua-cam.com/video/M56Ziy6p75g/v-deo.html
This is a perfect primer to our conversation about Zen and Mysticism if you still want to have it. Because they throw another wrench in the gears of the explainationist. Unlike a DMT trip a mystical experience can be had sober and what it presents is not an alternate world like DMT, but rather it presents the world we typically know in such a way that lets us know that our entire life we've been looking at a cheap reproduction of the world. That our normal daily experiences of the world are like a tiny cell phone image of a painting, and the mystical experience is like seeing the original painting in the museum, though we can obviously point to similarities between the stamp sized cell phone image there are also very big disparities. Or a better analogy would be like seeing a low-res VHS copy of a film originally presented on a 4K 3D IMAX projection on a multiple thousand inch diagonal screen. The mystical experience in some respect shows that the world as you always knew was always just a very very poor reproduction of the world. And the disparity or gap between normal life and the mystical state is a million times more pronounced than the examples cited above. The mystical state also has the uncanny effect of showing you that our normal explanatory frameworks are exactly what have been blocking us the whole time from seeing reality in its original form, we see the reproduction exactly on account of normal explanatory modalities and the way these modalities makes us take things for granted and blocks our ability to be acquainted with reality. And this is what Zen works to reveal to us through its methods.
Fascinating and clearly expressed. Thank you! (Currently tripping so while this is very fun stuff to think about, I'm going to have to come back to it sober😅)
Any chance you're going to make a video on the late wittgenstein's 'solution' for scepticism regarding the existence of other minds? I. e. his critique of the internal-object-model of psychological experiences and his private language argument?
The trouble with Wittgenstein is that I find him infuriating to read. Kinda puts me off doing a video on him. Though having said that, I'm currently planning a video on Moore's response to skepticism, and he's just as appalling as a writer (though bad in a very different way).
Excellent video, I especially liked the last two arguments: The one that said that stipulating an external world might be the one making unnecessary ontological commitments (ouch!), and the one that says that IBE is really missing the issue, which hit really hard. I'm an IBE fan but now I have a lot to reconsider, Thanks!
@Kane B : Hi Kane, Forgive me, but I have two questions that are unrelated to this video: (1) Have you read Mark Wilson’s “Wandering Significance”?, and (2) Will you ever complete the fabled last video of the “Quine on modality series”?
@@KaneB As for Mark Wilson’s “Wandering Significance”, it’s a highly original work-challenging, but well worth the investment of your time and energy. (2) As for (2) Thanks for answering anyway; that series already covers the essential areas.
Hey kane, what are your thoughts of the implications of moral anti realism towards our ethical behaviour - I feel like ethics would be less serious, in regards to compelling people to sacrifice things, and I feel like contractarian views might have synergy with moral skepticism, what is your thought on the matter, since often people claim that holding moral antirealism has no implication on our ethical behaviour, but I find this hard to believe
>> I feel like ethics would be less serious, in regards to compelling people to sacrifice things I disagree. The reason is that if moral realism were true, I would not care about what the moral facts are. I like to use the example of a "moral property detector". Suppose that there were moral facts, and suppose that we somehow built a detector that could track moral facts. It's a machine with a dial on it, and when we point it at different actions, the dial moves. We point it at somebody being enslaved and the dial moves far to the right; we point it at somebody giving to charity and the dial moves far to the left; we point it at somebody reading a book and the dial stays right where it is. For the most part, the machine delivers results that are in line with our moral attitudes. But then something surprising happens: whenever we point the detector at homosexual behaviour, the dial moves far to the right (the "morally wrong" part). It seems to me that, if you are a moral realist, this should give you pretty strong reason to believe that homosexuality is morally wrong. So how should we react to this? Well, I can only speak for myself. But I wouldn't care at all. Of course, granting that moral realism is true and that the moral property detector is reliable, I would have to say that it is an objective fact that homosexuality is morally wrong. But this would only be of academic interest. In everyday life, I would continue to promote acceptance of homosexuality, I would continue to condemn homophobia, etc. Why would it matter if homosexuality is objectively wrong, or if there is some categorical prescription that people should not be homosexuals? What this really amounts to is that the external world has a different attitude to me. But why should the fact that the external world has a different attitude to me have any more force than the fact that *other people* have different moral attitudes to me? Like, I already know that there are plenty of entities who think that homosexuality is morally wrong. When Frank expresses disapproval of homosexuality, this doesn't change *my* attitude to homosexuality. If it's an objective fact that homosexuality is wrong, I would see this as simply another entity with a different attitude to me. So I completely disagree that, under moral antirealism, morality would become "less serious". Indeed, I'm inclined to think you've got it exactly the wrong way round. It's the moral realists who do not take morality seriously. If moral realism is true, there is no reason to care about it. Morality would no longer be something that necessarily matters to us. At least, that's how I see it. >> and I feel like contractarian views might have synergy with moral skepticism It depends on the kind of contractarianism, and I guess on what you mean by "moral skepticism". It's hard to give a general answer to a question like this. A lot of contractarians think that there are universal moral truths, because the outcome of the contract would be binding on all rational agents, and these truths hold regardless of what anybody believes or values about morality. That seems like realism to me.
@@KaneB holy shit that was an awesome answer, especially the part with the dectetor. It addresses a lot of issues that I had with normative ethics! About the second part, i should have been more precise, i feel like an antirealist stance would have synergy with "making up" a contract that allows people to work towards their own good collectively, in a game-theoretic fashion. Im not sure if thats whats normalle understood as contractarian, but I feel like being more open to see self interest as not objectively wrong but still wanting to see humans cooperate and cultivate a healthy character might be addressed best if we understand our moral agreements as some kind of contract, even if it is not binding in an objective sense Btw do you use some platform that allows one time tips or donations, I only found your patreon so far
@@patrickthomasius I mean, I'm pretty attracted to something along the lines of contractarianism. But I think most contractarians assume that: (1) Moral norms are, as a matter of fact, grounded in the contract, so that people who simply deny contractarianism outright, and argue for a different foundation for moral norms, are making a mistake. (2) We discover moral truths that are universally binding. That is, there are certain rules constraining behaviour that all ideally rational, self-interested agents will accept. Over time, our moral theorizing will come to converge on these rules. This is more in line with realism. Having said that, I think a lot of people tend to associated contractarianism with metaethical constructivism. Though it's unclear whether constructivism is opposed to realism. >> Btw do you use some platform that allows one time tips or donations No, but only because I've never considered it before. Is there any particular platform that you'd suggest?
@@KaneB buy me a coffee is something that does the job, but I can also subscribe to your patreon for a short time instead, always great to get extensive answers and great content
It was said that the skeptical argument doesn't appeal to skeptical hypotheses, but surely a situation in which it merely appears that P IS a skeptical hypothesis. Also, doesn't Q1 presuppose a sort of deductivism or infallibilism whereby one knows only if one can infallibly and certainly distinguish two hypotheses? But the explanationist and I shall reply that knowledge isn't that strict, and one can simply use inductive and fallible knowledge.
I take it that the point is that the appearance that P holds regardless of whether or not P is the case. Even the anti-skeptic agrees that there is an appearance/reality distinction. Here's how Mizrahi puts the point: "appeals to skeptical hypotheses are redundant as far as [the appearance/reality argument] is concerned. For, whether any skeptical hypothesis obtains or not, it is often the case that distinguishing between P and the appearance as if P cannot be done by relying merely on the way things appear to one." Look at this way. For some proposition P about the external world, both the skeptic and the anti-skeptic affirm: (A) It appears that P is the case. The anti-skeptic will also affirm, whereas the skeptic will not affirm: (A*) P is the case. Surely we don't want to say that (A) is the skeptical hypothesis, since this proposition is affirmed by both the skeptic and the anti-skeptic. It also seems odd to say that merely failing to affirm (A*) counts as a skeptical hypothesis. The usual role of skeptical hypotheses is that they are thought to provide the grounds on which (A*) is resisted. That is, the reason why (A*) is not justified is because I don't know that I'm not a brain-in-a-vat, for example. >> Also, doesn't Q1 presuppose a sort of deductivism or infallibilism whereby one knows only if one can infallibly and certainly distinguish two hypotheses? I don't see why. Q1 only involves distinguishing between two claims, not infallibly distinguishing between two claims.
That's such a crap, trite approach. Inductive foundations will never overcome skepticism, it's so silly to think probabilities provide knowledge and aren't just reflections of limited perspectives on something that one *doesn't* know.
@@DarrenMcStravick If the skeptic concedes that we can have probabilities, then she's conceded everything that I want, at least. I think the genuine challenge comes from those skeptics who hold either that there are simply no grounds on which to make an assessment of the probability that CSH is true, or that there are such grounds, but that CSH turns out to be probably false.
Also, how can the Skeptic point to any appearance-reality distinction or the inability to distinguish between the two without thereby positing the existence of a reality and the appearance-reality distinction itself!
I'm confused about what the problem here is supposed to be. There is a distinction between horses and unicorns. But this doesn't commit me to the existence of unicorns.
The regular person shits,eats and drinks out of physical necessety. While the solipsists imagines himself eating, shitting and drinking out of some ocd i presume.
This doesn't really solve it. For the solipsist, if they don't go through the process of imagining eating, they will go through all the experiences of hunger, starvation, satiety, toxicity, etc. In that sense it doesn't even matter if it's real or imaginary, they have the same functional consequence.
@@uninspired3583 Im not sure what there is to solve? In your example it will be an imagined functional consequence. The point remains the same. There seems to be no diffrence between the two positions apart from language.
@@DeadEndFrog i see. I thought you were suggesting that the body can't be sustained by imagined apples, so I must have had a real one at breakfast. We don't need to solve the problem of solipsism to live daily lives, only to make firm claims about the way things actually are. I don't see why we need to make such claims though.
@@uninspired3583 I consider solipsism an non-issue, its something for the philosophers. imagine having to read all these books by other people, and then finding out it was you who imagined them all along. What a twist! Or we could just ignore that part, and look differentiate the things that matter. Knowlage i have before imagining interaction, and knowlage i have after- or as the solipsist would say, knowlage i have by the means of imagining others, and knowlage i have when imagining my mind privatly. Thats the the true destinction i care about. I tried to explain it before on these videos, but im either terrible at explaining, my english is terrible, or im wrong somewhere in my reasoning. But what i see is that there seems to be a form of 'necessety' thats very private, where people have to do x to get y. The solipsists do this when they have to argue with others to get new insights, rather then imagining coming up with it themselves. And thats all i care about. If reality could be like fantasy (for me) i wouldn't make a destinction, but since there seems to be a destinction in what i can achive by myself and in my fantasy, im bound to ask the question if solipsism solves this issue. And i don't think it does. Sorry for the ramble
@@DeadEndFrog I think it's kind of a placeholder. 0 isn't a quantity but serves an important purpose in math. In philosophy, solipsism demonstrates uncertainty because of the way perception works. It's the map, not the territory. Very few people actually hold solpsism to be true, but we use it in conversation as a reference point.
Inference to the best explanation would quickly run into problems as soon as people develop the technology to create actual brains in vats. If Alice were really a brain in a vat, we clearly couldn't accept her arguing that she knows she's not a brain in a vat by inference to the best explanation. She doesn't know she's not a brain in a vat because she's exactly a brain in a vat. Her inference must be invalid, and this goes to suggest that all inference to the best explanation arguments are invalid, unless there's some way in which Alice's argument is specifically invalid that doesn't apply to all other inference to the best explanation arguments. It seems that inference to the best explanation ought to be invalid, since it prioritizes preference above truth. It's a way of inferring whatever we think is best according to whatever criteria we choose. It works excellently if we have a particular conclusion we're hoping to reach, such as the common sense hypothesis, but logic shouldn't be about giving ourselves ways to confirm what we want to believe.
I think the explanationist would say that Alice is justified in believing that she's not a BIV. Of course, we know better, but then we have access to information that Alice doesn't. So the fact that we can't accept Alice's argument doesn't undermine Alice's justification. Along the same lines, it's a common enough view that e.g. scientists of the 1800s were justified in believing that Newtonian mechanics was true, even though we now know it to be false, on the basis of information that those scientists didn't have.
Believing that the external world exists seems to be an illusion that we all agree on. Do we know that this is real? CAN we know this is real? Will we ever know if this is real? I don't know and I don't know if we can ever know. But as of now, we've accepted this as reality and work to live this life the best we can...
If you're taking the external world to be an illusion, who's the "we"? Skepticism similarly undermines the justification for believing that there are any other people.
I note briefly in the video that a further important challenge to explanationism is that many philosophers reject inference to the best explanation in general. For more on this, most of the videos in my scientific realism series touch on the debate concerning IBE in science. I also discuss critiques of IBE and outline alternative approaches to epistemology in these videos:
How to be an empiricist - ua-cam.com/video/TSYKP6UKpwk/v-deo.html
Induction without rules - ua-cam.com/video/DY0-tRu0ms0/v-deo.html
Voluntarist epistemology - ua-cam.com/video/jHnx7ddV3fA/v-deo.html
My videos on laws of nature, mentioned at 34:08:
ua-cam.com/video/q4gjiVAQ3r0/v-deo.html
ua-cam.com/video/M56Ziy6p75g/v-deo.html
This is a perfect primer to our conversation about Zen and Mysticism if you still want to have it. Because they throw another wrench in the gears of the explainationist. Unlike a DMT trip a mystical experience can be had sober and what it presents is not an alternate world like DMT, but rather it presents the world we typically know in such a way that lets us know that our entire life we've been looking at a cheap reproduction of the world. That our normal daily experiences of the world are like a tiny cell phone image of a painting, and the mystical experience is like seeing the original painting in the museum, though we can obviously point to similarities between the stamp sized cell phone image there are also very big disparities. Or a better analogy would be like seeing a low-res VHS copy of a film originally presented on a 4K 3D IMAX projection on a multiple thousand inch diagonal screen. The mystical experience in some respect shows that the world as you always knew was always just a very very poor reproduction of the world. And the disparity or gap between normal life and the mystical state is a million times more pronounced than the examples cited above. The mystical state also has the uncanny effect of showing you that our normal explanatory frameworks are exactly what have been blocking us the whole time from seeing reality in its original form, we see the reproduction exactly on account of normal explanatory modalities and the way these modalities makes us take things for granted and blocks our ability to be acquainted with reality. And this is what Zen works to reveal to us through its methods.
Yes, I'm definitely still interested. I will contact you about that shortly. Just been a bit busy recently!
Fascinating and clearly expressed. Thank you! (Currently tripping so while this is very fun stuff to think about, I'm going to have to come back to it sober😅)
Any chance you're going to make a video on the late wittgenstein's 'solution' for scepticism regarding the existence of other minds? I. e. his critique of the internal-object-model of psychological experiences and his private language argument?
The trouble with Wittgenstein is that I find him infuriating to read. Kinda puts me off doing a video on him. Though having said that, I'm currently planning a video on Moore's response to skepticism, and he's just as appalling as a writer (though bad in a very different way).
Excellent video, I especially liked the last two arguments: The one that said that stipulating an external world might be the one making unnecessary ontological commitments (ouch!), and the one that says that IBE is really missing the issue, which hit really hard.
I'm an IBE fan but now I have a lot to reconsider, Thanks!
I like videos where you talk about skepticism I’d love to see other responses to the argument
@Kane B : Hi Kane,
Forgive me, but I have two questions that are unrelated to this video:
(1) Have you read Mark Wilson’s “Wandering Significance”?, and
(2) Will you ever complete the fabled last video of the “Quine on modality series”?
(1) It's been on my list for years but I still haven't gotten around to it.
(2) Probably not.
@@KaneB As for Mark Wilson’s “Wandering Significance”, it’s a highly original work-challenging, but well worth the investment of your time and energy.
(2) As for (2) Thanks for answering anyway; that series already covers the essential areas.
Hey kane, what are your thoughts of the implications of moral anti realism towards our ethical behaviour - I feel like ethics would be less serious, in regards to compelling people to sacrifice things, and I feel like contractarian views might have synergy with moral skepticism, what is your thought on the matter, since often people claim that holding moral antirealism has no implication on our ethical behaviour, but I find this hard to believe
>> I feel like ethics would be less serious, in regards to compelling people to sacrifice things
I disagree. The reason is that if moral realism were true, I would not care about what the moral facts are. I like to use the example of a "moral property detector". Suppose that there were moral facts, and suppose that we somehow built a detector that could track moral facts. It's a machine with a dial on it, and when we point it at different actions, the dial moves. We point it at somebody being enslaved and the dial moves far to the right; we point it at somebody giving to charity and the dial moves far to the left; we point it at somebody reading a book and the dial stays right where it is. For the most part, the machine delivers results that are in line with our moral attitudes. But then something surprising happens: whenever we point the detector at homosexual behaviour, the dial moves far to the right (the "morally wrong" part). It seems to me that, if you are a moral realist, this should give you pretty strong reason to believe that homosexuality is morally wrong. So how should we react to this?
Well, I can only speak for myself. But I wouldn't care at all. Of course, granting that moral realism is true and that the moral property detector is reliable, I would have to say that it is an objective fact that homosexuality is morally wrong. But this would only be of academic interest. In everyday life, I would continue to promote acceptance of homosexuality, I would continue to condemn homophobia, etc. Why would it matter if homosexuality is objectively wrong, or if there is some categorical prescription that people should not be homosexuals? What this really amounts to is that the external world has a different attitude to me. But why should the fact that the external world has a different attitude to me have any more force than the fact that *other people* have different moral attitudes to me? Like, I already know that there are plenty of entities who think that homosexuality is morally wrong. When Frank expresses disapproval of homosexuality, this doesn't change *my* attitude to homosexuality. If it's an objective fact that homosexuality is wrong, I would see this as simply another entity with a different attitude to me.
So I completely disagree that, under moral antirealism, morality would become "less serious". Indeed, I'm inclined to think you've got it exactly the wrong way round. It's the moral realists who do not take morality seriously. If moral realism is true, there is no reason to care about it. Morality would no longer be something that necessarily matters to us. At least, that's how I see it.
>> and I feel like contractarian views might have synergy with moral skepticism
It depends on the kind of contractarianism, and I guess on what you mean by "moral skepticism". It's hard to give a general answer to a question like this. A lot of contractarians think that there are universal moral truths, because the outcome of the contract would be binding on all rational agents, and these truths hold regardless of what anybody believes or values about morality. That seems like realism to me.
@@KaneB holy shit that was an awesome answer, especially the part with the dectetor. It addresses a lot of issues that I had with normative ethics! About the second part, i should have been more precise, i feel like an antirealist stance would have synergy with "making up" a contract that allows people to work towards their own good collectively, in a game-theoretic fashion. Im not sure if thats whats normalle understood as contractarian, but I feel like being more open to see self interest as not objectively wrong but still wanting to see humans cooperate and cultivate a healthy character might be addressed best if we understand our moral agreements as some kind of contract, even if it is not binding in an objective sense
Btw do you use some platform that allows one time tips or donations, I only found your patreon so far
@@patrickthomasius I mean, I'm pretty attracted to something along the lines of contractarianism. But I think most contractarians assume that: (1) Moral norms are, as a matter of fact, grounded in the contract, so that people who simply deny contractarianism outright, and argue for a different foundation for moral norms, are making a mistake. (2) We discover moral truths that are universally binding. That is, there are certain rules constraining behaviour that all ideally rational, self-interested agents will accept. Over time, our moral theorizing will come to converge on these rules.
This is more in line with realism. Having said that, I think a lot of people tend to associated contractarianism with metaethical constructivism. Though it's unclear whether constructivism is opposed to realism.
>> Btw do you use some platform that allows one time tips or donations
No, but only because I've never considered it before. Is there any particular platform that you'd suggest?
@@KaneB buy me a coffee is something that does the job, but I can also subscribe to your patreon for a short time instead, always great to get extensive answers and great content
I'm so gay for this channel and there's nothing you can do about it
ua-cam.com/video/-wTNTlWk3B8/v-deo.html
It was said that the skeptical argument doesn't appeal to skeptical hypotheses, but surely a situation in which it merely appears that P IS a skeptical hypothesis. Also, doesn't Q1 presuppose a sort of deductivism or infallibilism whereby one knows only if one can infallibly and certainly distinguish two hypotheses? But the explanationist and I shall reply that knowledge isn't that strict, and one can simply use inductive and fallible knowledge.
I take it that the point is that the appearance that P holds regardless of whether or not P is the case. Even the anti-skeptic agrees that there is an appearance/reality distinction. Here's how Mizrahi puts the point: "appeals to skeptical hypotheses are redundant as far as [the appearance/reality argument] is concerned. For, whether any skeptical hypothesis obtains or not, it is often the case that distinguishing between P and the appearance as if P cannot be done by relying merely on the way things appear to one."
Look at this way. For some proposition P about the external world, both the skeptic and the anti-skeptic affirm:
(A) It appears that P is the case.
The anti-skeptic will also affirm, whereas the skeptic will not affirm:
(A*) P is the case.
Surely we don't want to say that (A) is the skeptical hypothesis, since this proposition is affirmed by both the skeptic and the anti-skeptic. It also seems odd to say that merely failing to affirm (A*) counts as a skeptical hypothesis. The usual role of skeptical hypotheses is that they are thought to provide the grounds on which (A*) is resisted. That is, the reason why (A*) is not justified is because I don't know that I'm not a brain-in-a-vat, for example.
>> Also, doesn't Q1 presuppose a sort of deductivism or infallibilism whereby one knows only if one can infallibly and certainly distinguish two hypotheses?
I don't see why. Q1 only involves distinguishing between two claims, not infallibly distinguishing between two claims.
That's such a crap, trite approach. Inductive foundations will never overcome skepticism, it's so silly to think probabilities provide knowledge and aren't just reflections of limited perspectives on something that one *doesn't* know.
@@DarrenMcStravick If the skeptic concedes that we can have probabilities, then she's conceded everything that I want, at least. I think the genuine challenge comes from those skeptics who hold either that there are simply no grounds on which to make an assessment of the probability that CSH is true, or that there are such grounds, but that CSH turns out to be probably false.
I love you
💙
Also, how can the Skeptic point to any appearance-reality distinction or the inability to distinguish between the two without thereby positing the existence of a reality and the appearance-reality distinction itself!
I'm confused about what the problem here is supposed to be. There is a distinction between horses and unicorns. But this doesn't commit me to the existence of unicorns.
@@KaneB Doesn't this commit you to at least existence of unicorns as mental objects?
The regular person shits,eats and drinks out of physical necessety. While the solipsists imagines himself eating, shitting and drinking out of some ocd i presume.
This doesn't really solve it. For the solipsist, if they don't go through the process of imagining eating, they will go through all the experiences of hunger, starvation, satiety, toxicity, etc.
In that sense it doesn't even matter if it's real or imaginary, they have the same functional consequence.
@@uninspired3583 Im not sure what there is to solve? In your example it will be an imagined functional consequence. The point remains the same. There seems to be no diffrence between the two positions apart from language.
@@DeadEndFrog i see. I thought you were suggesting that the body can't be sustained by imagined apples, so I must have had a real one at breakfast.
We don't need to solve the problem of solipsism to live daily lives, only to make firm claims about the way things actually are. I don't see why we need to make such claims though.
@@uninspired3583 I consider solipsism an non-issue, its something for the philosophers.
imagine having to read all these books by other people, and then finding out it was you who imagined them all along. What a twist!
Or we could just ignore that part, and look differentiate the things that matter. Knowlage i have before imagining interaction, and knowlage i have after- or as the solipsist would say, knowlage i have by the means of imagining others, and knowlage i have when imagining my mind privatly.
Thats the the true destinction i care about.
I tried to explain it before on these videos, but im either terrible at explaining, my english is terrible, or im wrong somewhere in my reasoning.
But what i see is that there seems to be a form of 'necessety' thats very private, where people have to do x to get y. The solipsists do this when they have to argue with others to get new insights, rather then imagining coming up with it themselves.
And thats all i care about. If reality could be like fantasy (for me) i wouldn't make a destinction, but since there seems to be a destinction in what i can achive by myself and in my fantasy, im bound to ask the question if solipsism solves this issue.
And i don't think it does.
Sorry for the ramble
@@DeadEndFrog I think it's kind of a placeholder. 0 isn't a quantity but serves an important purpose in math.
In philosophy, solipsism demonstrates uncertainty because of the way perception works. It's the map, not the territory.
Very few people actually hold solpsism to be true, but we use it in conversation as a reference point.
Inference to the best explanation would quickly run into problems as soon as people develop the technology to create actual brains in vats. If Alice were really a brain in a vat, we clearly couldn't accept her arguing that she knows she's not a brain in a vat by inference to the best explanation. She doesn't know she's not a brain in a vat because she's exactly a brain in a vat. Her inference must be invalid, and this goes to suggest that all inference to the best explanation arguments are invalid, unless there's some way in which Alice's argument is specifically invalid that doesn't apply to all other inference to the best explanation arguments.
It seems that inference to the best explanation ought to be invalid, since it prioritizes preference above truth. It's a way of inferring whatever we think is best according to whatever criteria we choose. It works excellently if we have a particular conclusion we're hoping to reach, such as the common sense hypothesis, but logic shouldn't be about giving ourselves ways to confirm what we want to believe.
I think the explanationist would say that Alice is justified in believing that she's not a BIV. Of course, we know better, but then we have access to information that Alice doesn't. So the fact that we can't accept Alice's argument doesn't undermine Alice's justification. Along the same lines, it's a common enough view that e.g. scientists of the 1800s were justified in believing that Newtonian mechanics was true, even though we now know it to be false, on the basis of information that those scientists didn't have.
Believing that the external world exists seems to be an illusion that we all agree on. Do we know that this is real? CAN we know this is real? Will we ever know if this is real? I don't know and I don't know if we can ever know. But as of now, we've accepted this as reality and work to live this life the best we can...
If you're taking the external world to be an illusion, who's the "we"? Skepticism similarly undermines the justification for believing that there are any other people.
@@KaneB they/them/their
Abduction with deductive strength involving premises justified through direct acquaintance defeats skepticism everyday of the week.