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# Hempel's Paradox of the Ravens

 Posts: 266 Add as FriendChallenge to a DebateSend a Message 2/7/2015 1:02:05 AMPosted: 3 years agoThis has been an interesting topic to me always, because it makes the notion of "evidence" seem absurd. For those who don't know about it, here's the fast version:(Based on the assumption that "evidence" for a conditional statement A->B is when you have something that satisfies both A and B)Premise One: "All ravens are black" is equivalent to "If it is a raven it is black"Premise Two: "If it is a raven it is black" is equivalent to "If it is not black it is not a raven"Premise Three: If something is evidence for one statement, it is evidence for any equivalent statements.Premise Four: A white rock is evidence that "If it is not black it is not a raven"Conclusion: A white rock is evidence that all ravens are black.That's just my rushed summary, I'd recommend doing your own research for details. But what I'm asking is, can anyone think of a resolution to the paradox? Because I can't think of anything except that "evidence" doesn't really exist.Ceci n'est pas une signature.
 Posts: 4,343 Add as FriendChallenge to a DebateSend a Message 2/11/2015 3:23:14 PMPosted: 3 years agoAt 2/7/2015 1:02:05 AM, Surrealism wrote:This has been an interesting topic to me always, because it makes the notion of "evidence" seem absurd. For those who don't know about it, here's the fast version:(Based on the assumption that "evidence" for a conditional statement A->B is when you have something that satisfies both A and B)Premise One: "All ravens are black" is equivalent to "If it is a raven it is black"Premise Two: "If it is a raven it is black" is equivalent to "If it is not black it is not a raven"Premise Three: If something is evidence for one statement, it is evidence for any equivalent statements.Premise Four: A white rock is evidence that "If it is not black it is not a raven"Conclusion: A white rock is evidence that all ravens are black.That's just my rushed summary, I'd recommend doing your own research for details. But what I'm asking is, can anyone think of a resolution to the paradox? Because I can't think of anything except that "evidence" doesn't really exist.Premise 1 is flawed because albino ravens are whiteNah just kidding. In my opinion, the real problem lies in the definition of evidence. Why is a white rock considered evidence that "if it is not black it is not a raven?" Because it is an example of something that is not black, and therefore not a raven. But in order for it to be proof of the statement "if it is not black, it is not a raven", you'd need to also collect every other non-black object in the universe and show that none of them are ravens.Similarly, a white rock can be considered evidence that all ravens are black because in order to prove that all ravens are black, you need to sort all the objects in the universe into black and non-black, and then show that the black category contains all existing ravens. The white rock is a tiny piece of evidence in this case, as it is one of the non-black objects that cannot be a raven. If it were a raven, then since it lies outside of the black pile, your proof would fall apart. Thus in a roundabout way, it is evidence.
 Posts: 266 Add as FriendChallenge to a DebateSend a Message 2/11/2015 3:30:05 PMPosted: 3 years agoAt 2/11/2015 3:23:14 PM, ford_prefect wrote:At 2/7/2015 1:02:05 AM, Surrealism wrote:This has been an interesting topic to me always, because it makes the notion of "evidence" seem absurd. For those who don't know about it, here's the fast version:(Based on the assumption that "evidence" for a conditional statement A->B is when you have something that satisfies both A and B)Premise One: "All ravens are black" is equivalent to "If it is a raven it is black"Premise Two: "If it is a raven it is black" is equivalent to "If it is not black it is not a raven"Premise Three: If something is evidence for one statement, it is evidence for any equivalent statements.Premise Four: A white rock is evidence that "If it is not black it is not a raven"Conclusion: A white rock is evidence that all ravens are black.That's just my rushed summary, I'd recommend doing your own research for details. But what I'm asking is, can anyone think of a resolution to the paradox? Because I can't think of anything except that "evidence" doesn't really exist.Premise 1 is flawed because albino ravens are whiteNah just kidding. In my opinion, the real problem lies in the definition of evidence. Why is a white rock considered evidence that "if it is not black it is not a raven?" Because it is an example of something that is not black, and therefore not a raven. But in order for it to be proof of the statement "if it is not black, it is not a raven", you'd need to also collect every other non-black object in the universe and show that none of them are ravens.Similarly, a white rock can be considered evidence that all ravens are black because in order to prove that all ravens are black, you need to sort all the objects in the universe into black and non-black, and then show that the black category contains all existing ravens. The white rock is a tiny piece of evidence in this case, as it is one of the non-black objects that cannot be a raven. If it were a raven, then since it lies outside of the black pile, your proof would fall apart. Thus in a roundabout way, it is evidence.You are confusing evidence and proof. Proof certifies a statement as 100% true. Evidence merely brings knowledge to light that makes a statement more likely to be true.For me, the point of the paradox is to show that such a thing as evidence can't exist - that it can never be that something is more likely to be true, but that it is true or not.Ceci n'est pas une signature.
 Posts: 4,343 Add as FriendChallenge to a DebateSend a Message 2/11/2015 3:44:01 PMPosted: 3 years agoAt 2/11/2015 3:30:05 PM, Surrealism wrote:At 2/11/2015 3:23:14 PM, ford_prefect wrote:At 2/7/2015 1:02:05 AM, Surrealism wrote:This has been an interesting topic to me always, because it makes the notion of "evidence" seem absurd. For those who don't know about it, here's the fast version:(Based on the assumption that "evidence" for a conditional statement A->B is when you have something that satisfies both A and B)Premise One: "All ravens are black" is equivalent to "If it is a raven it is black"Premise Two: "If it is a raven it is black" is equivalent to "If it is not black it is not a raven"Premise Three: If something is evidence for one statement, it is evidence for any equivalent statements.Premise Four: A white rock is evidence that "If it is not black it is not a raven"Conclusion: A white rock is evidence that all ravens are black.That's just my rushed summary, I'd recommend doing your own research for details. But what I'm asking is, can anyone think of a resolution to the paradox? Because I can't think of anything except that "evidence" doesn't really exist.Premise 1 is flawed because albino ravens are whiteNah just kidding. In my opinion, the real problem lies in the definition of evidence. Why is a white rock considered evidence that "if it is not black it is not a raven?" Because it is an example of something that is not black, and therefore not a raven. But in order for it to be proof of the statement "if it is not black, it is not a raven", you'd need to also collect every other non-black object in the universe and show that none of them are ravens.Similarly, a white rock can be considered evidence that all ravens are black because in order to prove that all ravens are black, you need to sort all the objects in the universe into black and non-black, and then show that the black category contains all existing ravens. The white rock is a tiny piece of evidence in this case, as it is one of the non-black objects that cannot be a raven. If it were a raven, then since it lies outside of the black pile, your proof would fall apart. Thus in a roundabout way, it is evidence.You are confusing evidence and proof. Proof certifies a statement as 100% true. Evidence merely brings knowledge to light that makes a statement more likely to be true.No I'm not. Evidence is required to prove something. If you only have a little evidence, you can't prove the statement. But as you collect more evidence, the statement becomes more likely to be true, from your point of view. And when you have enough evidence to prove the statement, you accept it as true. So observing that a white rock is not a raven is evidence, not proof, of the statement "all ravens are black." If you were to observe every non-black object in the universe, and none of them were ravens, then you'd have proof that (assuming the existence of ravens) all ravens are black.For me, the point of the paradox is to show that such a thing as evidence can't exist - that it can never be that something is more likely to be true, but that it is true or not.It's not a paradox. People just don't understand that evidence can have a small or large magnitude. In this case the magnitude is tiny, but it is still evidence.