No you don't. This is what you imagine:Except I don't imagine ghosts to be electromagnetic radiation. I imagine them to be non-physical things. — Michael
How are ghosts shown in paintings, etc. ? Be honest with yourself. You can't imagine a non-physical thing. What you really mean by non-physical in this context is something that has a shape, but can go through walls, etc. that kinda stuff. — Agustino
Yes it does. You experience things like your thoughts and emotions, and you see that they're not always the same. But you wake up in the same bed (presumably). Because of its constancy, you deem one to be independent of your experience - it looks the same every time you come back to it - while the other - like dreaming, your mind, etc. you view it as depending on your experience. This concept arises precisely out of experience - more specifically the experience of the constancy of the external world, and the impossibility of altering it just by thinking about it. That's why you call it external in the first place.The concept of an external world doesn't come from experience at all, but from rational consideration. — Michael
Yes it does. You experience things like your thoughts and emotions, and you see that they're not always the same. But you wake up in the same bed (presumably). Because of its constancy, you deem one to be independent of your experience - it looks the same every time you come back to it - while the other - like dreaming, your mind, etc. you view it as depending on your experience. This concept arises precisely out of experience - more specifically the experience of the constancy of the external world, and the impossibility of altering it just by thinking about it. — Agustino
But simply having a veridical experience isn't evidence that it's a veridical experience, just as simply having the real painting isn't evidence that it's the real painting. — Michael
The evidence must allow you to rule out the possibility that you're wrong, and for that you need to recognise some distinguishing feature, as with the painting. — Michael
Now if having a waking experience defined as a state such that things necessarily match the way they appear to me, then if I'm having a waking experience I'm in a state which entails the presence of whatever that I perceive — Fafner
The trick here is in treating "waking experience" and "dreaming experience" as two different kinds of state, and this distinction is epistemically relevant because having a waking experience is by its very nature to perceive reliably how things are in the world, which is not the case with dreams. — Fafner
There's no reason to assume that whenever I know something, then I must be able to recognize all possible cases of deception or illusion. — Fafner
Sure, but the brain in the vat has no grounds to doubt that his experience is of an external world (and in some sense it is, because the electrical impulses stimulating his brain do come from an external world).A brain in a vat would also come to the same conclusion to explain the consistency of his experiences, despite the fact that none of his experiences are of an external world. — Michael
If you are in a waking state your experience is strongly correlated with how things are in your environment (otherwise it would not be a waking experience by definition), and hence it is correct to regard your perceptual states as good evidence. — Fafner
And thus the idea is that the inability to distinguish some hypothetical cases of dreaming from waking, doesn't prove that we can never distinguish dreaming from waking, since in a straightforward sense we often can do just that.
But how do you know how things are? You can't know that, you can only ever know how they appear to you. — BlueBanana
How so? If you are not, then it's possible that case of deception or illusion is true, and so you can't be sure things are how you think they're instead of you being deceived, ie. you don't know for sure. — BlueBanana
Sure, but the brain in the vat has no grounds to doubt that his experience is of an external world (and in some sense it is, because the electrical impulses stimulating his brain do come from an external world). — Agustino
Knowledge is that which we have when we don't have grounds for doubt. Knowledge can change and evolve. — Agustino
No, quite the contrary, the skeptic sets the bar for knowledge too high. He says knowledge only exists in the complete impossibility of doubt. And then he bases his doubt off logical possibility which is irrational.So you equate knowledge with certainty (in the sense of conviction). — Michael
Yes it does. Until further evidence, you know she hasn't cheated on you. You cannot rationally doubt her faithfulness if you have no reason to.I might not have any grounds to doubt my girlfriend's faithfulness, but that doesn't mean that I know she hasn't cheated on me. — Michael
Yes it does. Until further evidence, you know she hasn't cheated on you. You cannot rationally doubt her faithfulness if you have no reason to. — Agustino
I can't agree with that, because what we mean by truth is most often approximation. At least in most contexts we use it in.For one, I can only know that she hasn't cheated on me if she hasn't cheated on me. Knowledge requires truth, not just no reason to doubt. But then as Gettier showed, truth and justification are not sufficient either. — Michael
Well, if you have evidence that entails that things are the way the they seem, then I think it's very plausible to call it knowledge. — Fafner
But what if cases of illusion or deception are not actually possible, given the state the I'm right now in? (i.e., of not dreaming but being awake) — Fafner
Surely my not being able to recognize all cases of dreaming, don't prove that I'm actually dreaming right now! — Fafner
Simply having an accurate report isn't evidence that the report is accurate, and simply having veridical experiences isn't evidence that the experiences are veridical. — Michael
Far better to just stick with "experience of an external world" and "experience of an imaginary world". So the sceptical hypothesis is that we can't (or just don't) know if our experiences are of an external world or an imaginary world, and more strongly that the experiences that we ordinarily consider to be of an external world are actually of an imaginary world. — Michael
Well yes, having an accurate report doesn't prove by itself that your report is accurate — Fafner
And from the fact that you don't have some independent checks for the reliability of your report it doesn't follow that it is epistemically imprudent or irresponsible to rely on a report which looks to be a reliable report as far as one can tell
First, what even is this evidence you could have of things being as they seem? Second, knowledge in this context means 100% certain with absolutely no possibility of it being false in any hypothetical or theoretical situations, no matter how inplausible. So no, unless you can distinguish any deception or illusion, the claim is not palusible. — BlueBanana
No, but that's not the point. It proves that it's a possibility, even if the odds of that are one in infinity, and that there's no absolute proof of you being awake. — BlueBanana
So having a veridical experience doesn't prove that the experience is veridical. And the sceptic's claim is that we can't know that our experiences are veridical. — Michael
So in this case we have some means to test the accuracy of the report. We can check to see if things are as the report says. But what can we do to test the veridicality of an experience? How do we check to see if our experiences correspond to some external world? This is where we need to be able to recognise some feature that veridical experiences have and non-veridical experiences don't. — Michael
The fundamental problem with the notion of an external world experience is that it places the very thing that defines it as being an external world experience outside the experience. The brain in a vat has no way of knowing if his simulated world is an accurate representation of the external world. — Michael
The skeptic can claim this, but as I said many times, it doesn't follow from this that we cannot know anything about the external world. — Fafner
Surely the relevant question to ask whether I know that something is a cat is whether what I see appears as a cat - and the question whether I'm dreaming or something like that, has nothing to do with it.
I don't agree that the external world is "outside" our experience. And surely you have to know first whether there is actually an external world, in order to know whether it is outside our experience, don't you think?
You've phrased this very ambiguously. Let's say I meet a woman and that, unbeknown to me, she's your mother. In one sense it is correct to say that I know your mother, but in another sense it's wrong to say that I know that she's your mother.
The sceptic is saying something about the latter sort of knowledge. I can't know that the experience I'm having is an experience of an external world. — Michael
It has everything to do with that. The sceptical hypothesis is that we can't know that we're not brains in a vat, for example. No amount of examining cats is going to help us answer that. Unless there's some known feature that "real" cats have and simulated cats don't. — Michael
I think that's just true by definition. We say that some object is "external" if it exists when not being experienced. — Michael
Again, you are just assuming here that knowing that p requires the ability to detect every conceivable possibility of p being false, while I saying that such an assumption is unwarranted. Again, there's no much that I can add to what I already said on this point. — Fafner
How can you claim that knowing that p consists of anything other than excluding the possibility that p is false? If you can know that p, without excluding the possibility that p is false, then what does "knowing that" amount to? — Metaphysician Undercover
So my point is this - when you know that p, then your evidence must objectively entail the truth of p — Fafner
I didn't actually deny what you said that I denied (that knowing p means ruling out p's falsehood) - and I agree with you on this. I only disputed the claim that knowing must also entail being able to detect (from the subjects point of view) all cases of p's falsehood, and I think this is something else. — Fafner
What must rule out the possibility of falsehood is your objective evidence. So for example, if you are in a waking state perceiving a tree in full daylight, you cannot possibly be in this very same state and still be wrong about the tree. — Fafner
So my point is this - when you know that p, then your evidence must objectively entail the truth of p - — Fafner
Your approach seems to just be the truism that if the belief is true then it cannot be false. — Michael
But that's not what I'm saying. Compare the case of believing that there's a tree outside because you seem to see that there's a tree outside, and just guessing correctly that there's a tree outside. In the first case you are basing your belief on a capacity that within certain parameters (that is, in the right sort of environment) is an extremely reliable tree-detector (meaning it can detect real trees as opposed to fake trees, but not real trees as opposed to extremely vivid hallucinations). While in the second case of guessing you are not exercising any such a capacity, but merely depending on pure chance. But if you are exercising your tree detecting capacity in the right sort of environment, then it's not a matter of chance that you seem to see a tree whenever there are real trees (and not seeing trees when they are none), so there's an important difference between relying on perceptual experience, and merely guessing correctly — Fafner
In my example I see your blond mother, but I still don't know that your mother is blond. It's not enough that I exercise a reliable detecting capacity in the right sort of environment. I need periphery understanding (in this case, that the person I see is your mother). — Michael
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