lukeprog 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: Wei_Dai 09 June 2011 06:33:11PM *  8 points [-]

I share your skepticism about Luke's statement (but I've been waiting to criticize until he finishes his sequence to see if he addresses the problems later).

My goal here is to get people to feel the intuition that "I ought to do X" means something, and that thing is not "I think I ought to do X" or "I would think that I ought to do X if I were smarter and some other stuff".

To help pump that intuition, consider this analogy:

"X is true" (where X is a mathematical statement) means something, and that thing is not "I think X is true" or "I would think that X is true if I were smarter and some other stuff".

On the other hand, I think it's also possible that "I ought to do X" doesn't really mean anything. See my What does a calculator mean by "2"?. (ETA: To clarify, I mean some usages of "ought" may not really mean anything. There are some usages that clearly do, for example "If you want to accomplish X, then you ought to do Y" can in principle be straightforwardly reduced to a mathematical statement about decision theory, assuming that our current strong intuition that there is such a thing as "the right decision theory" is correct.)

Comment author: lukeprog 10 June 2011 08:11:04PM 3 points [-]

Wei Dai,

I would prefer to hear the source of your skepticism now, if possible. I anticipate not actually disagreeing. I anticipate that we will argue it out and discover that we agree but that my way of expressing my position was not clear to you at first. And then I anticipate using this information to improve the clarity of my future posts.

Comment author: Wei_Dai 11 June 2011 04:23:20AM 8 points [-]

I'll first try to restate your position in order to check my understanding. Let me know if I don't do it justice.

People use "should" in several different ways. Most of these ways can be "reducible to physics", or in other words can be restated as talking about how our universe is, without losing any of the intended meaning. Some of these ways can't be so reduced (they are talking about the world of "is not") but those usages are simply meaningless and can be safely ignored.

I agree that many usages of "should" can be reduced to physics. (Or perhaps instead to mathematics.) But there may be other usages that can't be so reduced, and which are not clearly safe to ignore. Originally I was planning to wait for you to list the usages of "should" that can be reduced, and then show that there are other usages that are not obviously talking about "the world of is" but are not clearly meaningless either. (Of course I hope that your reductions do cover all of the important/interesting usages, but I'm not expecting that to be the case.)

Since you ask for my criticism now, I'll just give an example that seems to be one of the hardest to reduce: "Should I consider the lives of random strangers to have (terminal) value?"

(Eliezer's proposal is that what I'm really asking when I ask that question is "Does my CEV think the lives of random strangers should have (terminal) value?" I've given various arguments why I find this solution unsatisfactory. One that is currently fresh on my mind is that "coherent extrapolation" is merely a practical way to find the answer to any given question, but should not be used as the definition of what the question means. For example I could use a variant of CEV (call it Coherent Extrapolated Pi Estimation) to answer "What is the trillionth digit of pi?" but that doesn't imply that by "the trillionth digit of pi" I actually mean "the output of CEPE".)

Comment author: lukeprog 11 June 2011 06:54:41AM 2 points [-]

I'm not planning to list all the reductions of normative language. There are too many. People use normative language in too many ways.

Also, I should clarify that when I talk about reducing ought statements into physical statements, I'm including logic. On my view, logic is just a feature of the language we use to talk about physical facts. (More on that if needed.)

Most of these ways can be "reducible to physics"... without losing any of the intended meaning.

I'm not sure I would say "most."

But there may be other usages that can't be so reduced, and which are not clearly safe to ignore.

What do you mean by "safe to ignore"?

If you're talking about something that doesn't reduce (even theoretically) into physics and/or a logical-mathematical function, then what are you talking about? Fiction? Magic? Those are fine things to talk about, as long as we understand we're talking about fiction or magic.

Should I consider the lives of random strangers to have (terminal) value?

What about this is hard to reduce? We can ask for what you mean by 'should' in this question, and reduce it if possible. Perhaps what you have in mind isn't reducible (divine commands), but then your question is without an answer.

Or perhaps you're asking the question in the sense of "Please fix my broken question for me. I don't know what I mean by 'should'. Would you please do a stack trace on the cognitive algorithms that generated that question, fix my question, and then answer it for me?" And in that case we're doing empathic metaethics.

I'm still confused as to what your objection is. Will you clarify?

Comment author: Wei_Dai 11 June 2011 07:57:11AM 4 points [-]

What do you mean by "safe to ignore"?

You said that you're not interested in an "ought" sentence if it reduces to talking about the world of is not. I was trying to make the same point by "safe to ignore".

If you're talking about something that doesn't reduce (even theoretically) into physics and/or a logical-mathematical function, then what are you talking about?

I don't know, but I don't think it's a good idea to assume that only things that are reducible to physics and/or math are worth talking about. I mean it's a good working assumption to guide your search for possible meanings of "should", but why declare that you're not "interested" in anything else? Couldn't you make that decision on a case by case basis, just in case there is a meaning of "should" that talks about something else besides physics and/or math and its interestingness will be apparent once you see it?

Or perhaps you're asking the question in the sense of "Please fix my broken question for me. I don't know what I mean by 'should'. Would you please do a stack trace on the cognitive algorithms that generated that question, fix my question, and then answer it for me?" And in that case we're doing empathic metaethics.

Maybe I should have waited until you finish your sequence after all, because I don't know what "doing empathic metaethics" actually entails at this point. How are you proposing to "fix my question"? It's not as if there is a design spec buried somewhere in my brain, and you can check my actual code against the design spec to see where the bug is... Do you want to pick up this conversation after you explain it in more detail?

Comment author: lukeprog 11 June 2011 04:59:58PM 2 points [-]

I don't think it's a good idea to assume that only things that are reducible to physics and/or math are worth talking about. I mean it's a good working assumption to guide your search for possible meanings of "should", but why declare that you're not "interested" in anything else?

Maybe this is because I'm fairly confident of physicalism? Of course I'll change my mind if presented with enough evidence, but I'm not anticipating such a surprise.

'Interest' wasn't the best word for me to use. I'll have to fix that. All I was trying to say is that if somebody uses 'ought' to refer to something that isn't physical or logical, then this punts the discussion back to a debate over physicalism, which isn't the topic of my already-too-long 'Pluralistic Moral Reductionism' post.

Surely, many people use 'ought' to refer to things non-reducible to physics or logic, and they may even be interesting (as in fiction), but in the search for true statements that use 'ought' language they are not 'interesting', unless physicalism is false (which is a different discussion, then).

Does that make sense? I'll explain empathic metaethics in more detail later, but I hope we can get some clarity on this part right now.

Comment author: Wei_Dai 11 June 2011 08:16:04PM 3 points [-]

Maybe this is because I'm fairly confident of physicalism? Of course I'll change my mind if presented with enough evidence, but I'm not anticipating such a surprise.

First I would call myself a radical platonist instead of a physicalist. (If all universes that exist mathematically also exist physically, perhaps it could be said that there is no difference between platonism and physicalism, but I think most people who call themselves physicalists would deny that premise.) So I think it's likely that everything "interesting" can be reduced to math, but given the history of philosophy I don't think I should be very confident in that. See my recent How To Be More Confident... That You're Wrong.

Comment author: lukeprog 12 June 2011 08:41:17AM 2 points [-]

Right, I'm pretty partial to Tegmark, too. So what I call physicalism is compatible with Tegmark. But could you perhaps give an example of what it would mean to reduce normative language to a logical-mathematical function - even a silly one?

Comment author: Wei_Dai 12 June 2011 10:15:34AM 2 points [-]

(It's late and I'm thinking up this example on the spot, so let me know if it doesn't make sense.)

Suppose I'm in a restaurant and I say to my dinner companion Bob, "I'm too tired to think tonight. You know me pretty well. What do you think I should order?" From the answer I get, I can infer (when I'm not so tired) a set of joint constraints on what Bob believes to be my preferences, what decision theory he applied on my behalf, and the outcome of his (possibly subconscious) computation. If there is little uncertainty about my preferences and the decision theory involved, then the information conveyed by "you should order X" in this context just reduces to a mathematical statement about (for example) what the arg max of a set of weighted averages is.

(I notice an interesting subtlety here. Even though what I infer from "you should order X" is (1) "according to Bob's computation, the arg max of ... is X", what Bob means by "you should order X" must be (2) "the arg max of ... is X", because if he means (1), then "you should order X" would be true even if Bob made an error in his computation.)

Comment author: lukeprog 12 June 2011 10:24:35AM 1 point [-]

Yeah, that's definitely compatible with what I'm talking about when I talk about reducing normative language to natural language (that is, to math/logic + physics).

Do you think any disagreements or confusion remains in this thread?

Comment author: Will_Sawin 13 June 2011 03:28:55PM 0 points [-]

For example I could use a variant of CEV (call it Coherent Extrapolated Pi Estimation) to answer "What is the trillionth digit of pi?" but that doesn't imply that by "the trillionth digit of pi" I actually mean "the output of CEPE"

(I notice an interesting subtlety here. Even though what I infer from "you should order X" is (1) "according to Bob's computation, the arg max of ... is X", what Bob means by "you should order X" must be (2) "the arg max of ... is X", because if he means (1), then "you should order X" would be true even if Bob made an error in his computation.)

Do you accept the conclusion I draw from my version of this argument?

Comment author: Vladimir_Nesov 11 June 2011 07:28:10PM 2 points [-]

Maybe this is because I'm fairly confident of physicalism? Of course I'll change my mind if presented with enough evidence, but I'm not anticipating such a surprise.

You'd need the FAI able to change its mind as well, which requires that you retain this option in its epistemology. To attack the communication issue from a different angle, could you give examples of the kinds of facts you deny? (Don't say "god" or "magic", give a concrete example.)

Comment author: lukeprog 12 June 2011 08:31:58AM *  0 points [-]

Yes, we need the FAI to be able to change its mind about physicalism.

I don't think I've ever been clear about what people mean to assert when they talk about things that don't reduce to physics/math.

Rather, people describe something non-natural or supernatural and I think, "Yeah, that just sounds confused." Specific examples of things I deny because of my physicalism are Moore's non-natural goods and Chalmers' conception of consciousness.

Comment author: Peterdjones 12 June 2011 07:50:34PM *  2 points [-]

I don't think I've ever been clear about what people mean to assert when they talk about things that don't reduce to physics/math.

SInce you can't actually reduce[*] 99.99% of your vocabulary, you're either so confused you couldn't possibly think or communicate...or you're only confused about the nature of confusion.

[*] Try reducing "shopping" to quarks, electrons and photons.You can't do it, and if you could, it would tell you nothing useful. Yet there is nothing that is not made of quarks,electrons and photons involved.

Comment author: Vladimir_Nesov 12 June 2011 11:04:19AM 0 points [-]

Specific examples of things I deny because of my physicalism are Moore's non-natural goods and Chalmers' conception of consciousness.

Not much better than "magic", doesn't help.

Comment author: lukeprog 12 June 2011 11:05:38AM 0 points [-]

Is this because you're not familiar with Moore on non-natural goods and Chalmers on consciousness, or because you agree with me that those ideas are just confused?

Comment author: Peterdjones 12 June 2011 08:11:28PM 1 point [-]

Dude, you really need to start distinguishing between reducible-in-principle and usefully-reducible and doesn't need-reducing.

Comment author: Will_Sawin 13 June 2011 03:23:51PM *  1 point [-]

If you're talking about something that doesn't reduce (even theoretically) into physics and/or a logical-mathematical function, then what are you talking about? Fiction? Magic?

That's making a pre-existing assumption that everyone speaks in physics language. It's circular.

Speaking in physic language about something that isn't in the actual physics is fiction. I'm not sure what magic is.

What is physics language? Physics language consists of statements that you can cash out, along with a physical world, to get "true" or "false"

What is moral language? Moral language consists of statements that you can cash out, along with a preference order on the set of physical worlds, to get "true" or "false".

ETA: IF you don't accept this, the first step is accepting that the statement "Flibber fladoo." does not refer to anything in physics, and is not a fiction.

Comment author: lukeprog 13 June 2011 04:30:40PM 0 points [-]

That's making a pre-existing assumption that everyone speaks in physics language

No, of course lots of people use 'ought' terms and other terms without any reduction to physics in mind. All I'm saying is that if I'm right about reductionism, those uses of ought language will fail to refer.

What is moral language? Moral language consists of statements that you can cash out, along with a preference order on the set of physical worlds, to get "true" or "false".

Sure, that's one way to use moral language. And your preference order is computed by physics.

Comment author: Will_Sawin 13 June 2011 05:01:55PM 4 points [-]

Sure, that's one way to use moral language.

That's the way I'm talking about, so you should be able to ignore the other ways in your discussion with me.

And your preference order is computed by physics.

You are proposing a function MyOrder from {states of the world} to {preference orders}

This gives you a natural function from {statements in moral language} to {statements in physical language}

but this is not a reduction, it's not what those statements mean, because it's not what they're defined to mean.

Comment author: lukeprog 14 June 2011 05:32:37PM *  1 point [-]

I think I must be using the term 'reduction' in a broader sense than you are. By reduction I just mean the translation of (in this case) normative language to natural language - cashing things out in terms of lower-level natural statements.

Comment author: Will_Sawin 14 June 2011 05:59:52PM 1 point [-]

But you can't reduce an arbitrary statement. You can only do so when you have a definition that allows you to reduce it. There are several potential functions from {statements in moral language} to {statements in physical language}. You are proposing that for each meaningful use of moral language, one such function must be correct by definition.

I am saying, no, you can just make statements in moral language which do not correspond to any statements in physical language.

Comment author: lukeprog 14 June 2011 06:19:51PM *  0 points [-]

You are proposing that for each meaningful use of moral language, one such function must be correct by definition

Not what I meant to propose. I don't agree with that.

you can just make statements in moral language which do not correspond to any statements in physical language.

Of course you can. People do it all the time. But if you're a physicalist (by which I mean to include Tegmarkian radical platonists), then those statements fail to successfully refer. That's all I'm saying.

Comment author: Vladimir_Nesov 11 June 2011 10:54:51AM *  1 point [-]

Also, I should clarify that when I talk about reducing ought statements into physical statements, I'm including logic. On my view, logic is just a feature of the language we use to talk about physical facts.

Logic can be used to talk about non-physical facts. Do you allow referring to logic even where the logic is talking about non-physical facts, or do you only allow referring to the logic that is talking about physical facts? Or maybe you taboo intended interpretation, however non-physical, but still allow the symbolic game itself to be morally relevant?

Comment author: lukeprog 11 June 2011 05:03:19PM 0 points [-]

Alas, I think this is getting us into the problem of universals. :)

With you, too, Vladimir, I suspect our anticipations do not differ, but our language for talking about these subtle things is slightly different, and thus it takes a bit of work for us to understand each other.

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

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.

Comment author: Vladimir_Nesov 11 June 2011 07:37:55PM *  0 points [-]

With you, too, Vladimir, I suspect our anticipations do not differ, but our language for talking about these subtle things is slightly different, and thus it takes a bit of work for us to understand each other.

This would require that we both have positions that accurately reflect reality, or are somehow synchronously deluded. This is a confusing territory, I know that I don't know enough to be anywhere confident in my position, and even that position is too vague to be worth systematically communicating, or to describe some important phenomena (I'm working on that). I appreciate the difficulty of communication, but I don't believe that we would magically meet at the end without having to change our ideas in nontrivial ways.

Comment author: lukeprog 12 June 2011 08:33:31AM 0 points [-]

I just mean that our anticipations do not differ in a very local sense. As an example, imagine that we were using 'sound' in different ways like Albert and Barry. Surely Albert and Barry have different anticipations in many ways, but not with respect to the specific events closely related to the tree falling in a forest when nobody is around.

Comment author: Peterdjones 12 June 2011 07:24:03PM 0 points [-]

If you're talking about something that doesn't reduce (even theoretically) into physics and/or a logical-mathematical function, then what are you talking about? Fiction? Magic?

Or maybe things that just don't usefully reduce.