All of AlephNeil's Comments + Replies

I have no special insight here but boring, cynical common sense suggests the following:

The big difference between now and the pre-ChatGPT era is that Google and a bunch of other massive competitors have woken up and want to blaze past OpenAI. For their part, OpenAI doesn't want there to be a perception that they have been overtaken, so will want to release on a fast enough schedule to be able to trump Google's latest and greatest. (Of course the arrival of something marketed as "GPT-5" tells us nothing about the true state of progress. The GPTs aren't natural kinds.)

You should be able to get it as a corollary of the lemma that given two disjoint convex subsets U and V of R^n (which are non-zero distance apart), there exists an affine function f on R^n such that f(u) > 0 for all u in V and f(v) < 0 for all v in V.

Our two convex sets being (1) the image of the simplex under the F_i : i = 1 ... n and (2) the "negative quadrant" of R^n (i.e. the set of points all of whose co-ordinates are non-positive.)

2cousin_it
Yeah, I think that works. Nice!

an authoritative payoff matrix that X can't safely calculate xerself.

Why not? Can't the payoff matrix be "read off" from the "world program" (assuming X isn't just 'given' the payoff matrix as an argument.)

0orthonormal
The one-player game that I wrote out is an example of a NDT agent trying to read off the payoff matrix from the world program, and failing. There are ways to ensure you read off the matrix correctly, but that's tantamount to what you do to implement CDT, so I'll explain it in Part II.
  1. Actually, this is an open problem so far as I know: show that if X is a Naive Decision Theory agent as above, with some analyzable inference module like a halting oracle, then there exists an agent Y written so that X cooperates against Y in a Prisoner's Dilemma while Y defects.

Let me just spell out to myself what would have to happen in this instance. For definiteness, let's take the payoffs in prisoner's dilemma to be $0 (CD), $1 (DD), $10 (CC) and $11 (DC).

Now, if X is going to co-operate and Y is going to defect then X is going to prove "If I... (read more)

0orthonormal
Your intuition that it gets deduced before any of the spurious claims like "if output = 'defect' then utility <= -$1" is taking advantage of an authoritative payoff matrix that X can't safely calculate xerself. I'm not sure that this tweaked version is any safer from exploitation...
AlephNeil220

[general comment on sequence, not this specific post.]

You have such a strong intuition that no configuration of classical point particles and forces can ever amount to conscious awareness, yet you don't immediately generalize and say: 'no universe capable of exhaustive description by mathematically precise laws can ever contain conscious awareness'. Why not? Surely whatever weird and wonderful elaboration of quantum theory you dream up, someone can ask the same old question: "why does this bit that you've conveniently labelled 'consciousness' actually... (read more)

0torekp
And the first thing we should recognize is that this "refinement" is arbitrary and unjustified.
0Mitchell_Porter
My problem is not with mathematically precise laws, my problem is with the objects said to be governed by the laws. The objects in our theories don't have properties needed to be the stuff that makes up experience itself. Quantum mechanics by itself is not an answer. A ray in a Hilbert space looks less like the world than does a scattering of particles in a three-dimensional space. At least the latter still has forms with size and shape. The significance of quantum mechanics is that conscious experiences are complex wholes, and so are entangled states. So a quantum ontology in which reality consists of an evolving network of states drawn from Hilbert spaces of very different dimensionalities, has the potential to be describing conscious states with very high-dimensional tensor factors, and an ambient neural environment of small, decohered quantum systems (e.g. most biomolecules) with a large number of small-dimensional tensor factors. Rather than seeing large tensor factors as an entanglement of many particles, we would see "particles" as what you get when a tensor factor shrinks to its smallest form. I emphasize again that an empirically adequate model of reality as evolving tensor network would still not be the final step. The final step is to explain exactly how to identify some of the complicated state vectors with individual conscious states. To do this, you have to have an exact ontological account of phenomenological states. I think Husserlian transcendental phenomenology has the best ideas in that direction. Once this is done, the way you state the laws of motion might change. Instead of saying 'tensor factor T with neighbors T0...Tn has probability p of being replaced by Tprime', you would say 'conscious state C, causally adjacent to microphysical objects P0...Pn, has probability p of evolving into conscious state Cprime' - where C and Cprime are described in a "pure-phenomenological" way, by specifying sensory, intentional, reflective, and whatever othe

The comprehension axiom schema (or any other construction that can be used by a proof checker algorithm) isn't enough to prove all the statements people consider to be inescapable consequences of second-order logic.

Indeed, since the second-order theory of the real numbers is categorical, and since it can express the continuum hypothesis, an oracle for second-order validity would tell us either that CH or ¬CH is 'valid'.

("Set theory in sheep's clothing".)

But the bigger problem is that we can't say exactly what makes a "silly" counterfactual different from a "serious" one.

Would it be naive to hope for a criterion that roughly says: "A conditional P ⇒ Q is silly iff the 'most economical' way of proving it is to deduce it from ¬P or else from Q." Something like: "there exists a proof of ¬P or of Q which is strictly shorter than the shortest proof of P ⇒ Q"?

A totally different approach starts with the fact that your 'lemma 1' could be proved without knowing anything about A. Perhaps this could be deemed a sufficient condition for a counterfactual to be serious. But I guess it's not a necessary condition?

6cousin_it
Both these approaches have been proposed on the workshop list. Good job figuring them out so quickly! I can make such a criterion fall into nasty Loebian traps by maliciously tweaking the formal system to make some proofs longer than others. That means any proof of correct behavior (like one-boxing) must rely on the intimate details of the proof enumeration order, but we have no idea how to talk formally about such things. A doesn't necessarily get the code of U neatly factored into A and everything else. The agent has to find copies of itself in the universe, it doesn't get told the positions of all copies explicitly. Note that if we replace the U in the post with some other U' that can be proven equivalent to U by S, then A can notice that equivalence, unscramble the code of U' into U, and win.

Suppose we had a model M that we thought described cannons and cannon balls. M consists of a set of mathematical assertions about cannons

In logic, the technical terms 'theory' and 'model' have rather precise meanings. If M is a collection of mathematical assertions then it's a theory rather than a model.

formally independent of the mathematical system A in the sense that the addition of some axiom A0 implies Q, while the addition of its negation, ~A0, implies ~Q.

Here you need to specify that adding A0 or ~A0 doesn't make the theory inconsistent, whic... (read more)

Perhaps a slightly simpler way would be to 'run all algorithms simultaneously' such that each one is slowed down by a constant factor. (E.g. at time t = (2x + 1) * 2^n, we do step x of algorithm n.) When algorithms terminate, we check (still within the same "process" and hence slowed down by a factor of 2^n) whether a solution to the problem has been generated. If so, we return it and halt.

ETA: Ah, but the business of 'switching processes' is going to need more than constant time. So I guess it's not immediately clear that this works.

I agree that definitions (and expansions of the language) can be useful or counterproductive, and hence are not immune from criticism. But still, I don't think it makes sense to play the Bayesian game here and attach probabilities to different definitions/languages being correct. (Rather like how one can't apply Bayesian reasoning in order to decide between 'theory 1' and 'theory 2' in my branching vs probability post.) Therefore, I don't think it makes sense to calculate expected utilities by taking a weighted average over each of the possible stances one can take in the mind-body problem.

2Vladimir_Nesov
Gosh, that's not useful in practice far more widely than that, and not at all what I suggested. I object to exempting any and all decisions from potential to be incorrect, no matter what tools for noticing the errors are available or practical or worth applying.

I don't understand the question, but perhaps I can clarify a little:

I'm trying to say that (e.g.) analytic functionalism and (e.g.) property dualism are not like inconsistent statements in the same language, one of which might be confirmed or refuted if only we knew a little more, but instead like different choices of language, which alter the set of propositions that might be true or false.

It might very well be that the expanded language of property dualism doesn't "do" anything, in the sense that it doesn't help us make decisions.

2Vladimir_Nesov
OK, the problem I was getting at is that adopting a definition usually has consequences that make some definitions better than others, thus not exempting them from criticism, with implication of their usefulness still possible to refute.

Of course, we haven't had any instances of jarring physical discontinuities not being accompanied by 'functional discontinuities' (hopefully it's clear what I mean).

But the deeper point is that the whole presumption that we have 'mental continuity' (in a way that transcends functional organization) is an intuition founded on nothing.

(To be fair, even if we accept that these intuitions are indefensible, it's remains to be explained where they come from. I don't think it's all that "bizarre".)

Nice sarcasm. So it must be really easy for you to answer my question then: "How would you show that my suggestions are less likely?"

Right?

1gwern
Do you have any argument that all our previous observations where jarring physical discontinuities tend to be associated with jarring mental discontinuities (like, oh I don't know, death) are wrong? Or are you just trying to put the burden of proof on me and smugly use an argument from ignorance?
AlephNeil-10

You really think there is logical certainty that uploading works in principle and your suggestions are exactly as likely as the suggestion 'uploading doesn't actually work'?

How would you show that my suggestions are less likely? The thing is, it's not as though "nobody's mind has annihilated" is data that we can work from. It's impossible to have such data except in the first-person case, and even there it's impossible to know that your mind didn't annihilate last year and then recreate itself five seconds ago.

We're predisposed to say that a j... (read more)

-1gwern
Yes. How bizarre of us to be so predisposed.

The identify of an object is a choice, a way of looking at it. The "right" way of making this choice is the way that best achieves your values.

I think that's really the central point. The metaphysical principles which either allow or deny the "intrinsic philosophical risk" mentioned in the OP are not like theorems or natural laws, which we might hope some day to corroborate or refute - they're more like definitions that a person either adopts or does not.

I don't see either as irrational

I have to part company here - I think it is ... (read more)

0Vladimir_Nesov
What do the definitions do?

For any particular proposal for mind-uploading, there's probably a significant risk that it doesn't work, but I understand that to mean: there's a risk that what it produces isn't functionally equivalent to the person uploaded. Not "there's a risk that when God/Ripley is watching everyone's viewscreens from the control room, she sees that uploaded person's thoughts are on a different screen from the original."

8gwern
Of course there is such a risk. We can't even do formal mathematics without significant and ineradicable risk in the final proof; what on earth makes you think any anti-zombie or anti-Riply proof is going to do any better? And in formal math, you don't usually have tons of experts disagreeing with the proof and final conclusion either. If you think uploading is so certain the risk it is fundamentally incorrect is zero or epsilon, you have drunk the koolaid.

If the rules of this game allow one side to introduce a "small intrinsic philosophical risk" attached to mind-uploading, even though it's impossible in principle to detect whether someone has suffered 'arbitrary Searlean mind-annihiliation', then surely the other side can postulate a risk of arbitrary mind-annihilation unless we upload ourselves. (Even ignoring the familiar non-Searlean mind-annihilation that awaits us in old age.)

Perhaps a newborn mind has a half-life of only three hours before spontaneously and undetectably annihilating itself.

8gwern
You really think there is logical certainty that uploading works in principle and your suggestions are exactly as likely as the suggestion 'uploading doesn't actually work'?

Excellent.

Perhaps m could serve as a 'location', so that you'd be more likely to meet opponents with similar m values to your own.

Thanks, this is all fascinating stuff.

One small suggestion: if you wanted to, there are ways you could eliminate the phenomenon of 'last round defection'. One idea would be to randomly generate the number of rounds according to an exponential distribution. This is equivalent to having, on each round, a small constant probability that this is the last round. To be honest though, the 'last round' phenomenon makes things more rather than less interesting.

Other ways to spice things up would be: to cause players to make mistakes with small probability (say a 1% chance of defecting when you try to co-operate, and vice versa); or have some probability of misremembering the past.

Conversely, when we got trolled an unspecified length of time ago, an incompetent crackpot troll who shall remain nameless kept having all his posts and comments upvoted by other trolls.

It would help if there was a restriction on how much karma one could add or subtract from a single person in a given time, as others are suggesting.

What interests me about the Boltzmann brain (this is a bit of a tangent) is that it sharply poses the question of where the boundary of a subjective state lies. It doesn't seem that there's any part X of your mental state that couldn't be replaced by a mere "impression of X". E.g. an impression of having been to a party yesterday rather than a memory of the party. Or an impression that one is aware of two differently-coloured patches rather than the patches themselves together with their colours. Or an impression of 'difference' rather than an im... (read more)

3Vladimir_Nesov
If you haven't decided what the circle should represent.

Every now and then I see a claim that if there were a uniform weighting of mathematical structures in a Tegmark-like 'verse---whatever that would mean even if we ignore the decision theoretic aspects which really can't be ignored but whatever---that would imply we should expect to find ourselves as Boltzmann mind-computations

The idea is this: Just as most N-bit binary strings have Kolmogorov complexity close to N, so most N-bit binary strings containing s as a substring have Kolmogorov complexity at least N - length(s) + K(s) - somethingsmall.

And now ap... (read more)

0Will_Newsome
Without having looked closely at the rest of your comment yet: Here I risk a meaningless map/territory distinction, and yet it seems straightforwardly possible that the local universe---the thing we care about most---is perfectly well modeled by a universal prior, whereas the ensemble---say, a stack of universal prior pancakes infinitely high with each pancake having a unique Turing language along the real number line---is more accurately described with something vaguely like a uniform prior. (I have no idea if this is useful, but maybe this is clearer if it wasn't already painfully sickeningly clear: non-technically, you gotsa cylinder Ensemble made up of infinite infinitely thin mini-cylinder Universes (universal priors), where each mini-cylinder (circle!) is tagged with a "language" that is arbitrarily close to the one above or below it ('close' in the sense that the languages of Scheme and Haskell are closer together than The Way Will Newsome Describes The World and Haskell). (As an extremely gratuitous detail I'm imagining the most commonly used strings in each language scribbled along the circumference of each mini-cylinder in exponentially decreasing font size and branching that goes exactly all the way around the circumference. If you zoom out a little bit to examine continuous sets of mini-cylinders, that slightly-less-mini-cylinder too has its own unique language: it's all overlapping. If you zoom out to just see the whole cylinder you get... nothing! Or, well, everything. If your theory can explain everything you have zero knowledge.) (In decision theory such a scenario really messes with our notions of timeless control---what does it mean, if anything, to be an equivalent or analogous algorithm of a decision algorithm that is located inside a pancake that is in some far-off part of the pancake stack, and thus written in an entirely different language? It's a reframing of the "controlling copies of you in rocks" question but where it feels more like you

Hmm, are you interpreting the results as "boo CEOs" then?

I'm only interpreting the result as "boo this fictional CEO".

How would you modify the experiment to return information closer to what was sought?

Well, what Knobe is looking for is a situation where subjects make their 'is' judgements partly on the basis of their 'ought' judgements. Abstractly, we want a 'moral proposition' X and a 'factual proposition' Y such that when a subject learns X, they tend to give higher credence to Y than when they learn ¬X. Knobe takes X = "... (read more)

[This comment is no longer endorsed by its author]Reply
AlephNeil180

Instead, the moral character of an action’s consequences also seems to influence how non-moral aspects of the action – in this case, whether someone did something intentionally or not – are judged.

Stupid Knobe effect. Obviously the subjects' responses were an attempt to pass judgement on the CEO. In one case, he deserves no praise, but in the other he does deserve blame [or so a typical subject would presumably think]. The fact that they were forced to express their judgement of moral character through the word 'intentional', which sometimes is a 'non-moral' quality of an action, doesn't tell us anything interesting.

2Vaniver
Your explanation is obviously correct; what's interesting about it is that it exists, and that's why it's 100% relevant.
0Morendil
Hmm, are you interpreting the results as "boo CEOs" then? How would you modify the experiment to return information closer to what was sought?
2Jonathan_Graehl
I thought of this too. Also a factor: publicly giving credit to someone makes you feel obligated to them.

Merely saying it wouldn't be so bad, as long as there was some substance behind the assertion.

But basically his argument boils down to this:

"If you dunk two wooden boards with wires poked through them into soapy water and then lift them out, the soaps films between the wires are the solution to an NP-hard problem. But creating the boards and wires and dunking them can be done in polynomial time. So as long as physics is Turing computable, P = NP."

This is a fantastically stupid argument, because you could easily create a simulation of the above pr... (read more)

4Normal_Anomaly
So far as I understand your comment, Bringsjord loses a lot of credibility. Thanks for explaining his argument from behind the paywall in your link. Also I looked at more of his paper on Singularitarians being fideists, and he says in the paper that there are arguments for the Singularity and he's going to "debunk" them. I'm starting to think he doesn't know what the word "fideist" means.

Yeah well, it's Selmer P = NP Bringsjord. He's a complete joke!

0Normal_Anomaly
That is indeed evidence against his credibility, if not particularly strong evidence for me. I don't know enough math to know directly that saying P=NP is a joke; I only believe it is because the math community says so.

I think what mathemajician means is that if the stream of data is random (in that the bits are independent random variables each with probability 1/2 of being 1) then Solomonoff induction converges on the uniform measure with high probability (probability 1, in fact).

I'm sure you knew that already, but you don't seem to realize that it undercuts the logic behind your claim:

The universal prior implies you should say "substantially less than 1 million".

O(BB^-1) (or whatever it is) is still greater than O(1) though, and (as best I can reconstruct it) your argument relies on there being a constant penalty.

2cousin_it
Yeah, kind of, but the situation still worries me. Should you expect the universe to switch away from the Born rule after you've observed 3^^^^3 perfectly fine random bits, just because the K-complexity of 3^^^^3 is small?

I think you're implicitly assuming that the K complexity of a hypothesis of the form "these n random bits followed by the observations predicted by H" equals n + (K-complexity of H) + O(1). Whereas actually, it's n + (K-complexity of H) + O(log(n)). (Here, the log(n) is needed to specify how long the sequence of random bits is).

So if you've observed a hugely long sequence of random bits then log(n) is getting quite large and 'switching universe' hypotheses get penalized relative to hypotheses that simply extend the random sequence.

This makes intu... (read more)

1cousin_it
You don't always need log(n) bits to specify n. The K-complexity of n is enough. For example, if n=3^^^^3, then you can specify n using much fewer bits than log(n). I think this kills your debunking :-)

The mathematical result is trivial, but its interpretation as the practical advice "obtaining further information is always good" is problematic, for the reason taw points out.

A particular agent can have wrong information, and make a poor decision as a result of combining the wrong information with the new information. Since we're assuming that the additional information is correct, I think it's reasonable to also stipulate that all previous information is correct.

Actually, I thought of that objection myself, but decided against writing it do... (read more)

It's true for anyone who understands random variables and expectations. There's a one line proof, after all.

Or in other words, the expectation of a max of some random variables is always greater or equal to the max of the expectations.

You could call this 'standard knowledge' but it's not the kind of thing one bothers to commit to memory. Rather, one immediately perceives it as true.

0Richard_Kennaway
Many things are obvious when they have been pointed out.
0PhilGoetz
Some people are criticizing this for being obviously true; others are criticizing it for being false. A particular agent can have wrong information, and make a poor decision as a result of combining the wrong information with the new information. Since we're assuming that the additional information is correct, I think it's reasonable to also stipulate that all previous information is correct. Also, you need to state the English interpretation in terms of expected value, not as "More information is never a bad thing".
0CuSithBell
That meets the criterion of "pithier", certainly.
1Will_Sawin
"one" is not general enough. Do you really think what you just said is true for all people?

What I'm really asking is, if some statement turns out to be undecidable for all of our models,

Nitpick: you don't mean "models" here, you mean "theories".

does that make that conjecture meaningless

Why should it?

or is undecidable somehow distinct from unverifiable.

Oh... you're implicitly assuming a 1920s style verificationism whereby "meaningfulness" = "verifiability". That's a very bad idea because most/all statements turn out to be 'unverifiable' - certainly all laws of physics.

As for mathematics, the word... (read more)

1Ronny Fernandez
Oh and I'm not talking about true or false in terms of provability (necessarily), don't forget that there is a semantic theory of truth for formal languages called model theory. Falsification or verification of a statement from a language by semantic means works just as well.
1Ronny Fernandez
You're right I do mean theory. But importantly I'm including the first order language that holds for the model of the natural numbers. So the interpreted first order language of the natural numbers is included in this usage of "theory". I'm using a 1920's (ish) style of verificationism that considers cases of P(T|S) ≠ P(T|~S) to be cases of a verifiable statement. See Ayler's Language, Truth, and Logic. The positivists always held that inductively verifiable statements are still verifiable and thus meaningful. What makes you say that all statements about the laws of physics are unverifiable? If it restricts your expectations for experience, it is a verifiable prediction. Certainly our hypothetical-deductive theories of the natural universe do in fact restrict our expected stimulus, and can be rejected on the grounds that the restrictions are not met. I'm using the word "verifiable" as it is used in Positivism and Verificationism. A statement S is verifiable if and only if S is a tautology or there is a strong inductive argument with S as the conclusion, which if cogent gives us a probability for S.
0TimFreeman
Thanks for the pointer to a free version of Hajek's "Waging War on Pascal's Wager" paper. One of his alternative formulations uses surreal numbers for utilities, much to my surprise. The main thrust is that either the utility of Heaven isn't the best possible thing, or it is the best possible thing and a mixed strategy of betting on heaven with probability p and betting on nothing with probability 1-p also gives infinite utility, for positive p. Thus, if Heaven is the best possible thing, Pascal's Wager doesn't rule out mixed strategies. If someone could check my math here -- I don't think surreal numbers let you assign a utility to the St. Petersburg paradox. The expected utility received at each step is 1, so the total utility is 1 + 1 + 1 + ... . Suppose that sum is X. Then X + 1 = X. This is not true for any surreal number, right?

You don't get to infer P from Q which is probably false, and then assert P with conviction.

What if I were to put P = "there is no such thing as absolute simultaneity" and Q = "special relativity"?

Or P = "the earth orbits the sun" and Q = "Newton's theory of gravity"?

0PhilosophyFTW
What you put in for P and Q is irrelevant, for a simple reason. If you're appealing to Q as your only evidence for P, and Q is probably false, then you don't have good evidence for for P. If Eliezer wants to appeal to some Q as his only evidence for P, and Q is probably false, then he has failed. Of course, if you have independent evidence for P, then you don't need to appeal to P as your evidence for Q (and you shouldn't, since P is very probably false). Here you can appeal to the independent evidence. For example, there is evidence that the earth orbits the sun that is independent of Newton's theory of gravity. It's for that reason that you find your toy examples plausible. This doesn't work when we're talking about QM. QM is a package deal that makes predictions. Evidence for the truth of many parts of the package come from the accurate predictions the package makes. Where there is independent evidence for the parts of the QM package Eliezer wants to appeal to, he should be appealing to those parts of the package and rely upon the independent evidence for them. Appealing to QM is just not rationally acceptable behavior for any reasonably informed persons.

Hyperreals or some other modification to the standard framework (see discussion of "infinity shades" in Bostrom) are necessary in order to say that a 50% chance of infinite utility is better than a 1/3^^^3 chance of infinite utility.

No it isn't, unless like Hayek you think there's something 'not blindingly obvious' about the 'modification to the standard framework' that consists of stipulating that probability p of infinite utility is better than probability q of infinite utility whenever p > q.

This sort of 'move' doesn't need a name. (What... (read more)

0CarlShulman
A system which selects actions so as to maximize the probability of receiving infinitely many units of some good, without differences in the valuation of different infinite payouts, approximates to a bounded utility function, e.g. assigning utility 1 to world-histories with an infinite payout of the good, and 0 to all other world-histories.
-1Will_Sawin
We are making the argument more formal. Doing so is a good idea in a wide variety of situations. Do you disagree with any of these claims? Introducing hyperreals makes the argument more formal Making an argument more formal is often good Here, making the argument more formal is more likely good than bad.
AlephNeil-10

Alan Hajek's article is one of the stupidest things I've ever read, and a depressing indictment on the current state of academic philosophy. Bunch of pointless mathematical gimmicks which he only thinks are impressive because he himself barely understands them.

That may be right, but I don't see how it conflicts with my (throwaway) remark.

"Quale" works better than "qualia" because (i) it sounds more like the word "claw" and (ii) it's singular whereas 'qualia' is plural.

0Tyrrell_McAllister
My remark was based on an error on my part. I forgot that qualia was the plural and quale was the singular, not the other way around.

Why is the difference relevant? I honestly can't imagine how someone could be in the position of 'feeling as though 2+2=4 is either necessarily true or necessarily false' but not 'feeling as though it's necessarily true'.

(FWIW I didn't downvote you.)

0[anonymous]
That seems to imply you think it would feel different than how you felt at first looking at my sum. Why, besides the fact that it's much simpler? I sort of agree, in the sense that "2+2 = 4" is a huge cliche and I have a hard time imagining how someone could not have memorized it in grade school, but that's part of the reason why I regard the "self-evidence" of this kind of claim as an illusion. We take shortcuts on simple questions.

If I say "37460225182244100253734521345623457115604427833 + 52328763514530238412154321543225430143254061105 = 8978898869677433866588884288884888725858488938" it should not immediately strike you as though I'm asserting a necessary truth that cannot possibly be otherwise.

It immediately strikes me that what you're asserting is either necessarily true or necessarily false, and whichever it is it could not be otherwise.

2[anonymous]
That's fine, but it's not at all the same thing.

Nitpick 1:

It seems likely to be the optimal way to build an AI that has to communicate with other AIs.

This seems a very contentious claim. For instance, to store the relative heights of people, wouldn't it make more sense to have the virtual equivalent of a ruler with markings on it rather than the virtual equivalent of a table of sentences of the form "X is taller than Y"?

I think the best approach here is just to explicitly declare it as an assumption: 'for argument's sake' your robot uses this method. End of story.

Nitpick 2:

Because of Gen

... (read more)
0Will_Sawin
Should I use a different postulate?

He's talking about the Lewis Carroll dialog that inspired the ones in GEB. "What the tortoise said to Achilles."

The point of the dialog is that there's something irreducibly 'dynamic' about the process of logical inference. Believing "A" and "A implies B" does not compel you to believe "B". Even if you also believe "A and (A implies B) together imply B". A static 'picture' of an inference is not itself an inference.

0Will_Sawin
There was supposed to be a link there but I accidentally deleted it. It's fixed.

Sure, R is recursively enumerable, but S and S_I are not.

The set S is the set of all total recursive functions. This is set in stone for all time. Therefore, there is only one way that S_I can refer to different things:

  1. Our stock of observational data may be different. In other words, the set I and the values of h(i) for i in I may be different.

But regardless of I and the values of h(i), it's easy to see that one cannot restrict S_I in the way you're attempting to do.

In fact, one can easily see that S_I = the set of functions of the form "if x is in I then h(x), otherwise f(x)" where f is an arbitra... (read more)

0PhilGoetz
So, we can rescue our utility function from the theorem if we are allowed to assign zero probability to arbitrary hypotheses that have no plausibility other than that they have not been absolutely ruled out. Such as the hypothesis that the laws of physics are valid at all times except on October 21, 2011. Being allowed to do this would make the counterexample work.

Goedel numbers are integers; how could anything that is enumerated by Goedel numbers not be enumerable? S_I, S, and R are all enumerable. The original paper says that R is the set of partial mu-recursive functions, which means computable functions; and the number of computable functions is enumerable.

You seem to be using 'enumerable' to mean 'countable'. (Perhaps you're confusing it with 'denumerable' which does mean countable.)

RichardKenneway means "recursively enumerable".

0PhilGoetz
You're right! But I may still be right that the set of functions in R is enumerable. (Not that it matters to my post.) There is a Turing function that can take a Goedel number, and produce the corresponding Goedel function. If you can define a programming language that is Turing-complete, and for which all possible strings are valid programs, then you just turn this function loose on the integers, and it enumerates the set of all possible Turing functions. Can this be done?

What I am doing is choosing the members of S_I.

You're not allowed to - de Blanc has already supplied a definition of S_I. One must either adopt his definition or be talking about something other than his result.

0PhilGoetz
He supplied a definition, not a particular set. I am using his definition, and providing one possible instantiation that is compatible with that definition.

No; the utility function is stipulated to be computable.

What Manfred is calling U(n) here corresponds to what the paper would call U(phi_n(k)).

0PhilGoetz
The utility function is defined as being computable over all possible input.

For simplicity we can make the "naive Bayesian" assumption that they're all independent,

But then for that to work, your prior belief that x + 1 > x, for really large x, has to begin very close to 1. If there was some delta > 0 such that the prior beliefs were bounded above by 1 - delta then the infinite product would always be zero even after Bayesian updates.

How would you know to have a prior belief that reallybignumber + 1 > reallybignumber even in advance of noticing the universal generalization?

0cousin_it
I cheat by assigning beliefs this way only in the "context" of checking this specific large statement :-) Maybe you could do it smarter by making the small statements non-independent. Will think. ETA: yeah, sure. What we actually need is P(S1)*P(S2|S1)*P(S3|S1,S2)*... The convergence of this infinite product seems to be a much easier sell.

Because then you can just number your possible outcomes by integers n and set p(n) to 1/U(n) * 1/2^n, which seems too easy to have been missed.

The reason why this wouldn't work is that sometimes what you're calling "U(n)" would fail to be well defined (because some computation doesn't halt) whereas p(n) must always return something.

0PhilGoetz
No; the utility function is stipulated to be computable.
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