Materialist don't agree with your premise so the argument fails — Gregory
But the "certainty" Descartes arrives at isn't knowledge! KILPOD - knowledge implies the logical possibility of doubt. — Bunji
1. Isn't the mind part of the body, or are you saying that your body is an illusion? If so, then what is the cause of your pain when you experience it?1. relating to the body as opposed to the mind.
2. relating to things perceived through the senses as opposed to the mind; tangible or concrete.
I'm focusing my attention on 2, but do include 1 in this, specifically the part where it says "perceived through the senses" and we know the senses are unreliable (think hallucinations) and can be deceived; if so, the physical could be an illusion. — TheMadFool
Is the following argument better?
1. All physical things are things perceived through the senses
2. All things perceived through the senses are things that could be illusions — TheMadFool
Absolutely not. His big mistake is to think that a foundation of indubitable certainty is required for knowledge. The kind of indubitable certainty he finds in the privacy of his own mind rules out the possibility of discovery, which is a necessary condition for knowledge. What Descartes takes to be knowledge is nothing of the sort, precisely because it rules out the logical possibility of doubt.Is Descartes position justified or not?
Well yes, the logical possibility of doubt exists here, because to know that no ant is an elephant it's necessary to know what an ant is and what an elephant is. These are cognitive achievements. If it's (logically) possible to doubt what an ant is or to doubt what an elephant is, then it's (logically) possible to doubt that no ant is an elephant. Descartes would certainly have said that this sort of proposition can be doubted, which is why the Cogito arrives at the proposition that it does. But for Wittgenstein, "No ant is an elephant" would count as knowledge, because the possibility of doubting it is logically possible. Ants and elephants are things to be discovered in the world.What about a proposition such as "No ant is an elephant"? Is there a way of doubting this?
Well yes, the logical possibility of doubt exists here, because to know that no ant is an elephant it's necessary to know what an ant is and what an elephant is. — Bunji
But how, knowing what "no ant is an elephant" means, is it possible to doubt it? Sure, I may not know the meaning of "ant" and/or I may not know the meaning of "elephant" but then I simply do not understand the proposition that no ant is an elephant...
And how do you justify the proposition that things are not simply what is meant? I can just say "that" is definitely not "this". Just look at the letters THAT THIS. You see the difference, right? What is different cannot be the same. It requires changing the subject from the concrete thing in question to it's essence to doubt this. But why would I want to change subjects?
And this already is where he changes subjects. He is not aware of the words anymore but silently makes the proposition those are perceived images. This changes the nature of things. But where did he get that undoubtable insight?According to Descartes the only certainty I have about THAT THIS is that I am aware of an image which appears to me as THAT THIS. — Bunji
Again, that is talking metaphysics. You do not take the things as they are anymore, but subsume them under some essence. But how would an assumed essence make THIS and THAT identical?It seems to me there's a difference between THAT and THIS, but my eyes could be deceiving me, or I could be imagining a difference that isn't really there, or I could be dreaming. — Bunji
No. The ability the differentiate the two is an obvious indicator of their difference. If you haveTo say "I know that THAT is not the same as THIS" seems somehow ridiculous. It's the sort of knowledge that is so taken for granted that it wouldn't usually occur to us to claim it as knowledge. But it is still open to the logical possibility of doubt. — Bunji
The word "ant" happens to refer to a certain type of insect, and "elephant" to a certain type of large, ruminant mammal, but it might have been otherwise (that it might have been otherwise is a logical possibility).
In conclusion, we can be certain of only one thing - the existence of minds - and we can always doubt the reality of the physical world, materialism. — TheMadFool
By what means are you aware of your own mind if not by sensing it? What does "perceived" mean? In what manner are you aware of your thinking? What form does thinking and perceiving take to say that you perceive your mind? — Harry Hindu
Then by what means are you aware of your mind? What does it mean to say that you are aware of your mind? What is the relationship between you and your mind? Thinking takes the same form that your senses provide. To say that you are thinking about your trip to the lake means that a visual, auditory and tactile image of the trip to the lake takes form in your mind. If the world is an illusion, then so is thinking.It seems to me that none of the five senses are required to make us aware of our minds. — EnPassant
1. Isn't the mind part of the body, or are you saying that your body is an illusion? If so, then what is the cause of your pain when you experience it? — Harry Hindu
By what means are you aware of your own mind if not by sensing it? What does "perceived" mean? In what manner are you aware of your thinking? What form does thinking and perceiving take to say that you perceive your mind? — Harry Hindu
Absolutely not. His big mistake is to think that a foundation of indubitable certainty is required for knowledge. The kind of indubitable certainty he finds in the privacy of his own mind rules out the possibility of discovery, which is a necessary condition for knowledge. What Descartes takes to be knowledge is nothing of the sort, precisely because it rules out the logical possibility of doubt. — Bunji
Thinking takes the same form that your senses provide. — Harry Hindu
I'm only concerned about the cogito ergo sum argument. Is it a sound argument or not?
"I think, therefore I am", is not a logically valid argument. To be valid it would need to take the form "If I think, then I exist. I think, therefore I exist." (modus ponens). If the premises of this argument are true, then the conclusion must also be true, but that is a mere tautology. The conclusion doesn't tell us anything more than the premises already tell us, so it doesn't give us any knowledge. Since the purpose of the Cogito argument is to provide a sound foundation of knowledge, it fails in that purpose even when transposed into a valid argument. — Bunji
No. The ability to differentiate the two is an obvious indicator of their difference. If you have A=A say "but in this case A was a B" this leads to B=B. It is still the same. Even if I (obligingly) wrote A=B with "B not=A" this would only prove that such a thing cannot be, logically.
Any ideas how to go about denying 2? — TheMadFool
Exactly."A=B & B not = A" is a logical contradiction. It doesn't provide us with knowledge because it's nonsense. — Bunji
First of all, you have again shifted the subject of discussion from "an elephant" to elephants. This again is asking for essence. I do not need to /say/ what the difference between two objects is, it is enough for them to be distinguishable. To subsume particular objects under some concept of "type" is not necessarily a valid starting point. And yet this seems to be what you are always trying to do here.But if I say "Elephants are different from antelopes", that is either true or false as a matter of empirical enquiry, not of logical necessity. — Bunji
But admitting that is not the same thing as admitting the possibility of doubt concerning the proposition that it actually does express. It is merely to allow the possibility that words used to express that proposition may have meant things other than they actually do. That is not doubt, that is just accepting alternative linguistic possibilities.
In any case, if you are attempting to lay down a necessary or sufficient or necessary and sufficient condition for what counts as knowable, you are not being very Wittgensteinian...
First of all, you have again shifted the subject of discussion from "an elephant" to elephants. This again is asking for essence. I do not need to /say/ what the difference between two objects is, it is enough for them to be distinguishable. To subsume particular objects under some concept of "type" is not necessarily a valid starting point. And yet this seems to be what you are always trying to do here.
If I point to a thing and label it an elephant I do not need to know what an elephant is besides the one thing I pointed to. So the proposition system you cite is not the criteria to call things elephants in the first place. So with Descartes. If we call the environment we live in "world" this is the definition of "world". It cannot be something else as this would imply a definition would be different from the thing. But the thing was the definition to start with.Only you are insisting that I keep shifting the subject from "an elephant" to "elephants", even though jkg20 has also gone from "no ant is an elephant" to "ants are not elephants". — Bunji
If I point to a thing and label it an elephant I do not need to know what an elephant is besides the one thing I pointed to.
Well, that depends on the reference of "x" doesn't it? I can imagine being uncertain whether a particular thing referred to by x in the expression "x is an ant" is indeed an ant or whether in fact a termite, for instance. That would be a case of questioning whether x is an ant or not, yet it is not, at least not clearly, a question about what "ant" means. It would be more natural to think that it was a question as to whether, given that the meaning of "ant" and "termite" are agreed, the x should be classed as one or the other. There might be cases where it really is not clear even to experts whether the x should be classed as an ant or a termite, and there one might think that it is actually the meaning of the terms that is being brought into question as well, but that is a very specific kind of case.To question whether or not x is an ant is to question what "ant" means.
An assumption is made that everything would need a cause. — Heiko
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