Vladimir_Nesov comments on A Defense of Naive Metaethics - Less Wrong

8 Post author: Will_Sawin 09 June 2011 05:46PM

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Comment author: Vladimir_Nesov 11 June 2011 07:51:35PM *  2 points [-]

By "logic referring to non-physical facts", do you have in mind something like "20+7=27"?

"3^^^^3 > 3^^^3", properties of higher cardinals, hyperreal numbers, facts about a GoL world, about universes with various oracles we don't have.

Things for which you can't build a trivial analogy out of physical objects, like a pile of 27 rocks (which are not themselves simple, but this is not easy to appreciate in the context of this comparison).

Comment author: lukeprog 12 June 2011 08:38:40AM 0 points [-]

Certainly, one could reduce normative language into purely logical-mathematical facts, if that was how one was using normative language. But I haven't heard of people doing this. Have you? Would a reduction of 'ought' into purely mathematical statements ever connect up again to physics in a possible world? If so, could you give an example - even a silly one?

Since it's hard to convey tone through text, let me explicitly state that my tone is a genuinely curious and collaboratively truth-seeking one. I suspect you've done more and better thinking on metaethics than I have, so I'm trying to gain what contributions from you I can.

Comment author: Vladimir_Nesov 13 June 2011 08:07:19PM *  2 points [-]

Certainly, one could reduce normative language into purely logical-mathematical facts, if that was how one was using normative language.

Why do you talk of "language" so much? Suppose we didn't have language (and there was only ever a single person), I don't think the problem changes.

Would a reduction of 'ought' into purely mathematical statements ever connect up again to physics in a possible world?

Say, I would like to minimize ((X-2)*(X-2)+3)^^^3, where X is the number I'm going to observe on the screen. This is a pretty self-contained specification, and yet it refers to the world. The "logical" side of this can be regarded as a recipe, a symbolic representation of your goals. It also talks about a number that is too big to fit into the physical world.

Comment author: lukeprog 14 June 2011 05:34:43PM 0 points [-]

Say, I would like to minimize ((X-2)*(X-2)+3)^^^3, where X is the number I'm going to observe on the screen. This is a pretty self-contained specification, and yet it refers to the world. The "logical" side of this can be regarded as a recipe, a symbolic representation of your goals. It also talks about a number that is too big to fit into the physical world.

Okay, sure. We agree about this, then.