Warrigal comments on Eliezer Yudkowsky Facts - Less Wrong

124 Post author: steven0461 22 March 2009 08:17PM

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Comment author: steven0461 23 March 2009 02:46:26PM 21 points [-]

Snow is white if and only if that's what Eliezer Yudkowsky wants to believe.

Comment author: [deleted] 18 October 2009 02:19:21AM 25 points [-]

Ironically, this is mathematically true. (Assuming Eliezer hasn't forsaken epistemic rationality, that is.) It's just that if Eliezer changes what he wants to believe, the color of snow won't change to reflect it.

Comment author: JohannesDahlstrom 01 April 2010 09:01:25AM 8 points [-]

It's just that if Eliezer changes what he wants to believe, the color of snow won't change to reflect it.

What?! Blasphemy!

Comment author: DanielLC 18 October 2010 05:34:28AM 19 points [-]

No, it's also mathematically true. He won't change what he wants to believe.

Comment author: MarkusRamikin 28 June 2011 10:50:30AM 0 points [-]

Hm. Isn't that what "and only if" would be about?

Comment author: [deleted] 28 June 2011 09:39:37PM 0 points [-]

In mathematics, an "if and only if" statement is defined as being true whenever its arguments are both true, or both false. "Snow is white" and "that's what Eliezer Yudkowsky wants to believe" are both true, so the statement is true.

Statements containing "if" often (usually?) have an implied "for all" in them, though. The implication here is something like "For all possible values of what-Eliezer-Yudkowsky-wants-to-believe, snow is white if and only if that's what Eliezer Yudkowsky wants to believe."

Comment author: MarkusRamikin 29 June 2011 06:29:14AM 0 points [-]

Hm. Yeah, that's how I read it. I'd say it this way, when I see an "if and only if", I see a statement about the whole truth table, not just the particular values of p and q that happen to hold. This is a mistake?

Comment author: [deleted] 29 June 2011 03:56:59PM 2 points [-]

I wouldn't call it a mistake. Your interpretation is probably the intended interpretation of the statement, and a more natural one. My interpretation is what you get when you translate the statement naively into formal logic.

Comment author: MarkusRamikin 29 June 2011 05:41:26PM 0 points [-]

Gotcha. Thanks for the replies.