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Cihan_Baran comments on What is Evidence? - Less Wrong

60 Post author: Eliezer_Yudkowsky 22 September 2007 06:43AM

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Comment author: Cihan_Baran 22 September 2007 11:09:13PM 1 point [-]

I don't know if it is just semantics but it seems to me that you are conflating evidence and our perception of that evidence, since you write:

"What is evidence? It is an event entangled, by links of cause and effect.. If the target of your inquiry is your shoelaces, for example, then the light entering your pupils is evidence entangled with your shoelaces."(Emphasis mine)(

Take the following thought experiment. Suppose Alan has untied shoelaces that he can see. Suppose that also Alan's shoelaces produce a barely audible sound when they are untied and suppose that Barbara can and does hear this sound, while Alan can't and doesn't.

Now if I interpret you correctly, your definition of evidence amounts to saying that Barbara and Alan have different evidence with regards to Alan's untied shoelaces. However, it seems more intuitive to say that there is the a single state of things, Alan's untied shoelaces, that constitutes the only evidence that's perceived differently by Barbara and Alan.

You also think that evidence is a type of event - of course, this would be true if evidence really was someone's perception of some state of affairs that led them to form true beliefs. But I believe that there are many types of evidence that simply are not events. What about mathematical evidence for some belief? Godel's incompleteness theorem is conclusive evidence for the fact that you can't derive all the true theorems of mathematics from a formal system. (Please don't boil me too much if I am like not totally correct.) Nevertheless, that theorem is not an event in time - it doesn't cause anything. Metaphorically, we might say a certain mathematical theorem might "cause" another one - or one theorem might be the immediate "consequence" of the other - but mathematical entailment relations are different from natural causation and all this talk is just metaphorical.

Lastly, you write that:

"Some belief systems, in a rather obvious trick to reinforce themselves, say that certain beliefs are only really worthwhile if you believe them unconditionally - no matter what you see, no matter what you think. Your brain is supposed to end up in the same state regardless. Hence the phrase, "blind faith". If what you believe doesn't depend on what you see, you've been blinded as effectively as by poking out your eyeballs."

However, I can think of some instances in which perhaps "blind faith" is warranted. For instance, I can not conceive of a situation that would make 2+2 = 4 false. Perhaps for that reason, my belief in 2+2=4 is unconditional.

Comment author: Ivan_Tishchenko 28 March 2010 09:07:34AM *  1 point [-]

However, I can think of some instances in which perhaps "blind faith" is warranted. For instance, I can not conceive of a situation that would make 2+2 = 4 false. Perhaps for that reason, my belief in 2+2=4 is unconditional

Yes, it is conditional. For example, I guess, if you had put two stones next to other two, then calculated and found that there is _five stones in total, that would be a proof that 2+2 not equal to 4. This is how your belief "2+2=4" could be falsified.

Comment author: Jack 28 March 2010 09:41:16AM *  3 points [-]

I know this is Eliezer's line but it still looks like nonsense to me. This experience would be evidence stones have a tendency to spontaneously appear when four stones are put next to each other.

Comment author: dylgramac 16 December 2010 06:44:01PM 2 points [-]

I have a simpler reason that the belief 2+2 = 4 is not blind. When he says he has blind faith because "I can not conceive of a situation that would make 2+2 = 4 false." it is not blind because he is trying to find an alternative rather than entirely avoiding questioning his belief.