Esar comments on Mixed Reference: The Great Reductionist Project - Less Wrong

29 Post author: Eliezer_Yudkowsky 05 December 2012 12:26AM

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Comment author: [deleted] 08 December 2012 12:23:03AM 0 points [-]

As I said above, "Some properties are not reducible to physics or logic." is a meaningful statement that is incompatible with the GRT world-view. It is meaningful, though it may be false; if the denial of GRT were meaningless, then GRT would be a tautology, and Eliezer would assign it Pr approaching 1, whereas in fact he assigns it Pr .5.

So we're assuming for the purposes of your argument here that the GRT is about meaningfulness, and we should distinguish this from your (and perhaps EY's) considered view of the GRT. So lets call the 'meaningfulness' version I attributed to EY GRTm, and the one you attribute to him GRTt.

We can gloss the difference thusly: the GRTt states that anything true must be expressible in physical+logical, or merely logical terms (tautologies, etc.).

The GRTm states that anything true or false must be expressible physical+logical, or merely logical terms.

Your argument appears to be that on the GRTm view, the sentence "some properties are not reducible to physics or logic" would be meaningless rather than false. You take this to be a reductio, because that sentence is clearly meaningful and false. Why do you think that, on the GRTm, this sentence would be meaningless? The GRTm view, along with the GRTt view, allows that false statements can be meaningful. And I see no reason to think that the above sentence couldn't be expressed in physics+logic, or merely logical terms.

So I'm not seeing the force of the reductio. You don't argue for the claim that "some properties are not reducible to physics or logic" would be meaningless on the GRTm view, so could you go into some more detail there?

Comment author: RobbBB 08 December 2012 12:48:16AM *  2 points [-]

One way to get at what I was saying above is that GRTt asserts that all true statements are analyzable into truth-conditions that are purely physical/logical, while GRTm asserts that all meaningful statements are analyzable into truth-conditions that are purely physical/logical. If we analyze "Some properties are not reducible to physics or logic." into physical/logical truth-conditions, we find that there is no state we can describe on which it is true; so it becomes a logical falsehood, a statement that is false given the empty set of assumptions. Equally, GRTm, if meaningful, is a tautology if we analyze its meaning in terms of its logico-physically expressible truth-conditions; there is no particular state of affairs we can describe in logico-physical terms in which GRTm is false.

But perhaps focusing on analysis into truth-conditions isn't the right approach. Shifting to your conception of GRTm and GRTt, can you find any points where Eliezer argues for GRTm? An argument for GRTm might have the following structure:

  1. Some sentences seem to assert non-physical, non-logical things.
  2. But the non-physicologicality of those things makes those sentences meaningless.
  3. So non-physicologicality in general probably makes statements meaningless.

On the other hand, if Eliezer is really trying to endorse GRTt, his arguments will instead look like this:

  1. Some sentences seem to be true but non-physicological.
  2. But those sentences are either false or analyzable/reducible to purely physicological truths.
  3. So non-physicological truths in general are probably expressible purely physicologically.

Notice that the latter argumentative approach is the one he takes in this very article, where he introduces 'The Great Reductionist Project.' This gives us strong reason to favor GRTt as an interpretation over GRTm, even though viewed in isolation some of his language does suggest GRTm. Is there any dialectical evidence in favor of the alternative interpretation GRTm? (I.e., evidence derived from the structure of his arguments.)

Comment author: [deleted] 08 December 2012 02:28:18AM 1 point [-]

Here's my exchange with EY:

In your latest sequence article, you described the great reductionist thesis as "the proposition that everything meaningful can be expressed this way [i.e. physics and/or logic] eventually."

Another LWer and I are in a debate over your intention here. One of us thinks that you must mean "everything true (and not necessarily everything false) can be expressed this way"

The other thinks you mean "everything true and everything false (i.e. everything meaningful) can be expressed this way".

Can you clear this up for us?

EY replied:

Everything true and most meaningful false statements can be expressed this way. Sufficiently confused verbal statements may have no translation, even as a set of logical axioms possessing no model, yet still be operable as slogans. I.e. "Like all members of my tribe, I firmly believe that clams up without no finger inside plus plus claims in the clams without no finger!"

So I replied:

So, just to be super clear (since I'm now losing this argument) you mean that there are statements that are both meaningful and false, but are not expressible in the terms you describe in Logical Pinpointing, Causal Reference, and Mixed Reference?

And he said:

Nope. That statement is meaningless is false.

So I'm actually not much less confused. His first reply seems to support GRTt. His second reply (the first word of it anyway) seems to support GRTm. Thoughts?

Comment author: RobbBB 08 December 2012 03:17:29AM *  0 points [-]

Thanks for taking the time to hunt down the facts!

I think "Everything true and most meaningful false statements can be expressed this way." is almost completely clear. Unless a person is being deliberately ambiguous, saying "most P are Q" in ordinary English conversation has the implicature "some P aren't Q."

I'm not even clear on what the grammar of "That statement is meaningless is false." is, much less the meaning, so I can't comment on that statement. I'm also not clear on how broad "the terms you describe in Logical Pinpointing, Causal Reference, and Mixed Reference" are; he may think that he's sketched meaningfulness criteria somewhere in those articles that are more inclusive than "The Great Reductionist Project" itself allows.

Comment author: [deleted] 08 December 2012 05:03:41AM 0 points [-]

I'm also not clear on how broad "the terms you describe in Logical Pinpointing, Causal Reference, and Mixed Reference" are; he may think that he's sketched meaningfulness criteria somewhere in those articles that are more inclusive than "The Great Reductionist Project" itself allows.

I think that was fairly clear. Each of those articles is explicitly about a form of reference sentences can have: logical, physical, or logicophysical, and his statement of the GRT was just that all meaningful (or in your reading, true) things can be expressed in these ways.

But it occurs to me that we can file something away, and tomorrow I'm going to read over your last three or four replies and think about the GRTt whether or not it's EY's view. That is, we can agree that the GRTm view is not a tenable thesis as we understand it.

Comment author: RobbBB 08 December 2012 05:19:37AM 0 points [-]

One possible source of confusion: What is the meaning of the qualifier "physical"? "Physical," "causal," "verifiable," and "taboo-able/analyzable" all have different senses, and it's possible that for some of them Eliezer is more willing to allow meaningful falsehoods than for others.

Comment author: RobbBB 08 December 2012 05:13:05AM 0 points [-]

Yeah. I'll re-read his posts, too. In all likelihood I didn't even think about the ambiguity of some of his statements, because I was interpreting everything in light of my pet theory that he subscribes to GRTt. I think he does subscribe to GRTt, but I may have missed some important positivistic views of his if I was only focusing on the project of his he likes. Some of the statements you cited where he discusses 'meaning' do create a tension with GRTt.

Comment author: Eliezer_Yudkowsky 08 December 2012 06:02:44PM 0 points [-]

My reply to this conversation so far is at:

Comment author: [deleted] 08 December 2012 01:44:30AM 1 point [-]

You'd just about convinced me, until I reread the OP and found it consistently and unequivocally discussing the question of meaningfulness. So before we go on, I'm just going to PM Eliezer and ask him what he meant. I'll let you know what he says if he replies.

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