fubarobfusco comments on Rationality Quotes September 2012 - Less Wrong

7 Post author: Jayson_Virissimo 03 September 2012 05:18AM

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Comment author: fubarobfusco 04 September 2012 05:22:16PM 1 point [-]

If someone tells you the opposite of the truth in order to deceive you, and you believe the opposite of what they say because you know they are deceitful, then you believe the truth. (A knave is as good as a knight to a blind bat.) The problem is, a clever liar doesn't lie all the time, but only when it matters.

Comment author: DanielLC 06 September 2012 08:00:03AM 2 points [-]

It's more likely that they're a stupid liar than that they got it all wrong by chance.

Comment author: TheOtherDave 04 September 2012 05:35:00PM 1 point [-]

Another problem is that for many interesting assertions X, opposite(opposite(X)) does not necessarily equal X. Indeed, opposite(opposite(X)) frequently implies NOT X.

Comment author: Alejandro1 05 September 2012 01:42:28PM 0 points [-]

Could you give an example? I would have thought this happens with Not(opposite(X)); for example, "I don't hate you" is different than "I love you", and in fact implies that I don't. But I would have thought "opposite" was symmetric, so opposite(opposite(X)) = X.

Comment author: TheOtherDave 05 September 2012 03:18:34PM 2 points [-]

Well, OK. So suppose (to stick with your example) I love you, and I want to deceive you about it by expressing the opposite of what I feel. So what do I say?

You seem to take for granted that opposite("I love you") = "I hate you." And not, for example, "I am indifferent to you." Or "You disgust me." Or various other assertions. And, sure, if "I love you" has a single, unambiguous opposite, and the opposite also has a single, unambiguous opposite, then my statement is false. But it's not clear to me that this is true.

If I end up saying "I'm indifferent to you" and you decide to believe the opposite of that... well, what do you believe?

Of course, simply negating the truth ("I don't love you") is unambiguously arrived at, and can be thought of as an opposite... though in practice, that's often not what I actually do when I want to deceive someone, unless I've been specifically accused of the truth. ("We're not giant purple tubes from outer space!")