Strilanc

Karma: 543

Strilanc Jan 14, 2015, 11:44 PM
1 point
in reply to: Luke_A_Somers’s comment on: Quantum cat-stencil interference projection? What is this?
Well...

The bomb tester does have a more stringent restriction than the camera. The framing of the problems is certainly different. They even have differing goals, which affect how you would improve the process (e.g. you can use grover’s search algorithm to make the bomb tester more effective but I don’t think it matters for the camera; maybe it would make it more efficient?)

BUT you could literally use their camera as a drop-in replacement for the simplest type of bomb tester, and vice versa. Both are using an interferometer. Both want to distinguish between something being in the way or not being in the way on one leg. Both use a detector that only fires when the photon “takes the other leg” and hits a detector that it counterfactually could not have if there was no obstruction on the sampling leg.

So I do think that calling the (current) camera a more involved version of the (basic) bomb tester makes sense and acts as a useful analogy.

Strilanc Jan 14, 2015, 8:06 AM
0 points
on: Quantum cat-stencil interference projection? What is this?
I think this is just a more-involved version of the Elitzur-Vaidman bomb tester. The main difference seems to be that they’re going out of their way to make sure the photons that interact with the object are at a different frequency.

The quantum bomb tester works by relying on the fact that the two arms interfere with each other to prevent one of the detectors from going off. But if there’s a measure-like interaction on one arm, that cancelled-out detector starts clicking. The “magic” is that it can click even when the interaction doesn’t occur. (I think the many worlds view here is that the bomb blew up in one world, creating differences that prevented it from ending up in the same state as. and thus interfering with. the non-bomb-blowing-up worlds.)

Strilanc Jan 8, 2015, 12:02 AM
4 points
in reply to: calef’s comment on: Comments on “When Bayesian Inference Shatters”?

This is an attempt at a “plain Jane” presentation of the results discussed in the recent arxiv paper

… [No concrete example given] …

Urgh...

Strilanc Jan 5, 2015, 7:26 PM
4 points
in reply to: Omid’s comment on: Open thread Jan. 5-11, 2015
- Write the password down on paper and keep that paper somewhere safe.
- Practice typing it in. Practice writing it down. Practice singing it in your head.
- Set things up so you have to enter it periodically.

Strilanc Dec 17, 2014, 9:03 AM
2 points
in reply to: Luke_A_Somers’s comment on: Help us Optimize the Contents of the Sequences eBook
A concrete example of a paper using the add-i-to-reflected-part type of beam splitter is the “Quantum Cheshire Cats” paper:

A simple way to prepare such a state is to send a horizontally polarized photon towards a 50:50 beam splitter, as depicted in Fig. 1. The state after the beam splitter is |Psi>, with |L> now denoting the left arm and |R> the right arm; the reflected beam acquires a relative phase factor i.

The figure from the paper:

I also translated the optical system into a similar quantum logic circuit:

Note that I also included the left-path detector they talk about later in the paper, and some read-outs that show (among other things) that the conditional probability of the left-path detector having gone off, given that D1 went off, is indeed 100%. (The circuit editor I fiddle with is here.)

It’s notable that my recreation uses gates with different global phase factors (the beam splitter is 1/2-i/2 and 1/2+i/2 instead of 1/sqrt(2) and i/sqrt(2)). It also ignores the mirrors that appear once on both paths. The effect is the same because global phase factors don’t matter.

edit My ability to make sign errors upon sign errors is legendary and hopefully fixed.

Strilanc Dec 16, 2014, 7:36 PM
5 points
in reply to: KatjaGrace’s comment on: Superintelligence 14: Motivation selection methods
Possible analogy: Was molding the evolutionary path of wolves, so they turned into dogs that serve us, unethical? Should we stop?

Strilanc Dec 13, 2014, 4:10 PM
2 points
on: [Resolved] Is the SIA doomsday argument wrong?
Wait, I had the impression that this community had come to the consensus that SIA vs SSA was a problem along the lines of “If a tree falls in the woods and no one’s around, does it make a sound?”? It finds an ambiguity in what we mean by “probability”, and forces us to grapple with it.

In fact, there’s a well-upvoted post with exactly that content.

The Bayesian definition of “probability” is essentially just a number you use in decision making algorithms constrained to satisfy certain optimality criteria. The optimal number to use in a decision obviously depends on the problem, but the unintuitive and surprising thing is that it can depend on details like how forgetful you are and whether you’ve been copied and how payoffs are aggregated.

The post I linked gave some examples:
- If Sleeping Beauty is credited a cumulative dollar every time she guesses correctly, she should act as if she assigns a probability of ¹⁄₂ to the proposition.
- If Sleeping Beauty is given a dollar only if she guesses correctly in all cases, otherwise nothing, then she should act as if she assigns a probability of ¹⁄₃ to the proposition.
Other payoff structures give other probabilities. If you never recombine Sleeping Beauty, then the problem starts to become about whether or not she values her alternate self getting money and what she believes her alternate self will do.

Strilanc Dec 9, 2014, 5:50 PM
14 points
0
in reply to: Scott Alexander’s comment on: No, Really, I’ve Deceived Myself

I would be happy to prove my “faith” in science by ingesting poison after I’d taken an antidote proven to work in clinical trials.

This is one of the things James Randi is known for. He’ll take a “fatal” dose of homeopathic sleeping pills during talks (e.g. his TED talk) as a way of showing they don’t work.

Strilanc Nov 21, 2014, 5:51 PM
2 points
in reply to: Luke_A_Somers’s comment on: What do you mean by Pascal’s mugging?

I am pretty sick of 1% being given as the natural lowest error rate of humans on anything. It’s not.

Hmm. Our error rate moment to moment may be that high, but it’s low enough that we can do error correction and do better over time or as a group. Not sure why I didn’t realize that until now.

(If the error rate was too high, error correction would be so error-prone it would just introduce more error. Something analogous happens in quantum error correction codes).

Strilanc Nov 17, 2014, 6:41 PM
5 points
on: AI caught by a module that counterfactually doesn’t exist
Oh, so M is not a stock-market-optimizer it’s a verify-that-stock-market-gets-optimized-er.

I’m not sure how this differs from a person just asking the AI if it will optimize the stock market. The same issues with deception apply: the AI realizes that M will shut it off, so it tells M the stock market will totally get super optimized. If you can force it to tell M the truth, then you could just do the same thing to force it to tell you the truth directly. M is perhaps making things more convenient, but I don’t think it’s solving any of the hard problems.

Strilanc Nov 17, 2014, 6:30 PM
5 points
on: Can science come to understand consciousness? A problem of philosophical zombies (Yes, I know, P-zombies again.)
It’s extremely premature to leap to the conclusion that consciousness is some sort of unobservable opaque fact. In particular, we don’t know the mechanics of what’s going on in the brain as you understand and say “I am conscious”. We have to at least look for the causes of these effects where they’re most likely to be, before concluding that they are causeless.

People don’t even have a good definition of consciousness that cleanly separates it from nearby concepts like introspection or self-awareness in terms of observable effects. The lack of observable effects goes so far that people posit they could get rid of consciousness and everything would happen the same (i.e. p-zombies). That is not a unassailable strength making consciousness impossible to study, it is a glaring weakness implying that p-zombie-style consciousness is a useless or malformed concept.

I completely agree with Eliezer on this one: a big chunk of this mystery should dissolve under the weight of neuroscience.

Strilanc Nov 12, 2014, 3:58 AM
12 points
in reply to: Gunnar_Zarncke’s comment on: Rationality Quotes November 2014
… wait, what? You can equate predicates of predicates but not predicates?!

(Two hours later)

Well, I’ll be damned...

Strilanc Nov 11, 2014, 5:59 PM
1 point
on: Superintelligence 9: The orthogonality of intelligence and goals
What are other examples of possible motivating beliefs? I find the examples of morals incredibly non-convincing (as in actively convincing me of the opposite position).

Here’s a few examples I think might count. They aren’t universal, but they do affect humans:
- Realizing neg-entropy is going to run out and the universe will end. An agent trying to maximize average-utility-over-time might treat this as a proof that the average is independent of its actions, so that it assigns a constant eventual average utility to all possible actions (meaning what it does from then on is decided more by quirks in the maximization code, like doing whichever hypothesized action was generated first or last).
- Discovering more fundamental laws of physics. Imagine an AI was programmed and set off in the 1800s, before anyone knew about quantum physics. The AI promptly discovers quantum physics, and then...? There was no rule given for how to maximize utility in the face of branching world lines or collapse-upon-measurement. Again the outcome might come down to quirks in the code; on how the mapping between the classical utilities and quantum realities is done (e.g. if the AI is risk-averse then its actions could differ based on if was using Copenhagen or Many-worlds).
- Learning you’re not consistent and complete. An agent built with an axiom that it is consistent and complete, and the ability to do proof by contradiction, could basically trash its mathematical knowledge by proving all things when it finds the halting problem / incompleteness theorems.
- Discovering an opponent that is more powerful than you. For example, if an AI proved that Yahweh, god of the old testament, actually existed then it might stop mass-producing paperclips and start mass-producing sacrificial goats or prayers for paperclips.

Strilanc Oct 21, 2014, 12:07 AM
3 points
on: Can AIXI be trained to do anything a human can?

For instance, if anything dangerous approached the AIXI’s location, the human could lower the AIXI’s reward, until it became very effective at deflecting danger. The more variety of things that could potentially threaten the AIXI, the more likely it is to construct plans of actions that contain behaviours that look a lot like “defend myself.” [...]

It seems like you’re just hardcoding the behavior, trying to get a human to cover all the cases for AIXI instead of modifying AIXI to deal with the general problem itself.

I get that you’re hoping it will infer the general problem, but nothing stops it from learning a related rule like “Human sensing danger is bad.”. Since humans are imperfect at sensing danger, that rule will better predict what’s happening compared to the actual danger you want AIXI to model. Then it removes your fear and experiments with nuclear weapons. Hurray!

Strilanc Oct 17, 2014, 7:14 PM
5 points
in reply to: travisrm89’s comment on: What false beliefs have you held and why were you wrong?
Anthropomorphically forcing the world to have particular laws of physics by more effectively killing yourself if it doesn’t seems… counter-productive to maximizing how much you know about the world. I’m also not sure how you can avoid disproving MWI by simply going to sleep, if you’re going to accept that sort of evidence.

(Plus quantum suicide only has to keep you on the border of death. You can still end up as an eternally suffering almost-dying mentally broken husk of a being. In fact, those outcomes are probably far more likely than the ones where twenty guns misfire twenty times in a row.)

Strilanc Oct 17, 2014, 12:46 AM
20 points
0
in reply to: hydkyll’s comment on: What false beliefs have you held and why were you wrong?
I find Eliezer’s insistence about Many-Worlds a bit odd, given how much he hammers on “What do you expect differently?”. Your expectations from many-worlds are be identical to those from pilot-wave, so....

I’m probably misunderstanding or simplifying his position, e.g. there are definitely calculational and intuition advantages to using one vs the other, but that seems a bit inconsistent to me.

Strilanc Aug 25, 2014, 3:57 PM
15 points
on: Open thread, 25-31 August 2014
Is there an existing post on people’s tendency to be confused by explanations that don’t include a smaller version of what’s being explained?

For example, confusion over the fact that “nothing touches” in quantum mechanics seems common. Instead of being satisfied by the fact that the low-level phenomena (repulsive forces and the Pauli exclusion principle) didn’t assume the high-level phenomena (intersecting surfaces), people seem to want the low-level phenomena to be an aggregate version of the high-level phenomena. Explaining something without using it is one of the best properties an explanation can have, but people are somehow unsatisfied by such explanations.

Other examples of “but explain(X) doesn’t include X!”: emotions from biology, particles from waves, computers from solid state physics, life from chemistry.

More controversial examples: free will, identity, [insert basically any other introspective mental concept here].

Examples of the opposite: any axiom/assumption of a theory, billiard balls in Newtonian mechanics, light propagating through the ether, explaining a bar magnet as an aggregation of atom-sized magnets, fluid mechanics using continuous fields instead of particles, love from “God wanted us to have love”.

Strilanc Aug 14, 2014, 5:56 PM
23 points
in reply to: zzrafz’s comment on: [LINK] Speed superintelligence?

Mario, for instance, once you jump, there’s not much to do until he actually lands

Mario games let you change momentum while jumping, to compensate for the lack of fine control on your initial speed. This actually does matter a lot in speed runs. For example, Mario 64 speedruns rely heavily on a super fast backwards long jump that starts with switching directions in the air.

A speed run of real life wouldn’t start with you eating lunch really fast, it would start with you sprinting to a computer.

Strilanc Jul 31, 2014, 7:12 PM
3 points
on: Announcing the 2014 program equilibrium iterated PD tournament
In the examples you show how to run the opponent, but how do you access the source code? For example, how do you distinguish a cooperate bot from a (if choice < 0.0000001 then Defect else Cooperate) bot without a million simulations?

Strilanc Jul 6, 2014, 3:30 AM
0 points
in reply to: Shmi’s comment on: [LINK] Claustrum Stimulation Temporarily Turns Off Consciousness in an otherwise Awake Patient
That sounds like what I expected. Have any links?