asr

Karma: 1,675

asr 4 Aug 2015 3:26 UTC
2 points
in reply to: DataPacRat’s comment on: Open thread, Aug. 03 - Aug. 09, 2015
It’s a tempting thought. But I think it’s hard to make the math work that way.

I have a lovely laptop here that I am going to give you. Suppose you assign some utility U to it. Now instead of giving you the laptop, I give you a lottery ticket or the like. With probability P I give you the laptop, and with probability 1 - P you get nothing. (The lottery drawing will happen immediately, so there’s no time-preference aspect here.) What utility do you attach to the lottery ticket? The natural answer is P * U, and if you accept some reasonable assumptions about preferences, you are in fact forced to that answer. (This is the basic intuition behind the von Neumann-Morgenstern Expected Utility Theorem.)

Given that probabilities are real numbers, it’s hard to avoid utilities being real numbers too.

asr 13 Mar 2015 3:32 UTC
3 points
in reply to: [deleted]’s comment on: Recovering the past

This is because the current position, direction, and speed of an atom (and all other measurements that can be done physically) are only possible with one and only one specific history of everything else in the universe.

This seems almost certainly false. You can measure those things to only finite precision—there is a limit to the number of bits you can get out of such a measurement. Suppose you measure position and velocity to one part in a billion in each of three dimensions. That’s only around 200 bits—hardly enough to distinguish all possible universal histories.

asr 11 Mar 2015 14:11 UTC
3 points
in reply to: Gondolinian’s comment on: Harry Potter and the Methods of Rationality discussion thread, March 2015, chapter 119

Good point. A time limit of 3:54 does seem too arbitrary to be hard-coded.

Hrm. Maybe it’s exactly one Atlantean time unit? Unsafe to assume that the units we are used to are the same units that the Stone’s maker would find natural.

asr 4 Mar 2015 22:03 UTC
7 points
in reply to: MarkusRamikin’s comment on: Harry Potter and the Methods of Rationality discussion thread, March 2015, chapter 116

I bet Hermione is just going to love being the center of all the attention and scrutiny this will bring on her.

She came back from the dead. Gonna be a lot of attention and scrutiny regardless.

asr 3 Mar 2015 15:42 UTC
2 points
in reply to: [deleted]’s comment on: Towards a theory of nerds… who suffer.

I have this impression—parenting hardly ever discussed on LW—that most of the community has no children.

Let me give you an alternate explanation. Being a parent is very time-consuming. It also tends to draw one’s interest to different topics than are typically discussed here. In consequence, LW readers aren’t a random sample of nerds or even of people in the general social orbit of the LW crowd. I would not draw any adverse inferences from the fact that a non-parenting-related internet forum tend to be depleted of parents.

asr 9 Feb 2015 5:55 UTC
0 points
in reply to: [deleted]’s comment on: Natural Selection of Government Systems
This graph would be more interesting and persuasive with a better caption.

asr 21 Jan 2015 21:24 UTC
6 points
in reply to: Vika’s comment on: Purchasing research effectively open thread

data scientists / statisticians mostly need access to computing power, which is fairly cheap these days.

This is true for each marginal data scientist. But there’s a catch, which is that those folks need data. Collecting and promulgating that data, in the application domains we care about, can sometimes be very costly. You might want to consider some of those as part of the cost for the data science.

For example, many countries are spending a huge amount of money on electronic health records, in part to allow better data mining. The health records aren’t primarily for scientific purposes, but making them researcher-friendly is a big indirect cost. Similarly, the census is a very expensive data-collection process that enables a lot of “cheap” analytics downstream.

While each data scientist might be cheap, there was a big up-front investment, at the national level, to enable them.

asr 21 Jan 2015 18:27 UTC
2 points
in reply to: alienist’s comment on: What topics are appropriate for LessWrong?

Um, yes for most definitions of “rational”. That’s why [autism] is considered a disability.

Hrm? A disability is a thing that is limits the disabled individual from a socially-recognized set of normal actions. The term ‘disability’ alone doesn’t imply anything about reasoning or cognitive skills. It seems at best un-obvious, and more likely false, that “rationality” encompasses all cognitive functions.

Some people have dyslexia; that is certainly a cognitive disability. It would be strange (not to say offensive) to describe dyslexic individuals as per se irrational. I suspect similarly for, say, dyscalculia. Or for that matter, short-term memory problems.

Autism is a big complicated bundle of traits and behaviors. Why are those behaviors “irrational” in a way that dyslexia isn’t?

asr 20 Jan 2015 22:22 UTC
2 points
on: The Unique Games Conjecture and FAI: A Troubling Obstacle
One of the unfortunate limitations of modern complexity theory is that a set of problems that look isomorphic sometimes have very different complexity properties. Another awkwardness is that worst-case complexity isn’t a reliable guide to practical difficulty. “This sorta feels like a coloring problem” isn’t enough to show it’s intractable on the sort of instances we care about.

Separately, it’s not actually clear to me whether complexity is good or bad news. If you think that predicting human desires and motivations is infeasible computationally, you should probably worry less about super intelligent AI, since that complexity barrier will prevent the AI from being radically effective at manipulating us.

It would seem to require an unusually malicious universe for a superhuman AI to be feasible, for that AI to be able to manipulate us efficiently, but for it to be infeasible for us to write a program to specify constraints that we would be happy with in retrospect.

asr 9 Jan 2015 7:10 UTC
1 point
in reply to: buybuydandavis’s comment on: Some recent evidence against the Big Bang

I just observe that a lot of cosmology seems to be riding on the theory that the red shift is caused by an expanding universe.

This seems wrong to be. There’s at least two independent lines of evidence for the Big Bang theory besides redshifts—isotope abundances (particularly for light elements) and the cosmic background radiation.

What if it light just loses energy as it travels, so that the frequency shifts lower?

We would have to abandon our belief in energy conservation. And we would then wonder why energy seems to be conserved exactly in every interaction we can see. Also we would wonder why we see spontaneous redshifts not spontaneous blue shifts. Every known micro-scale physical process in the universe is reversible [1], and by the CPT theorem, we expect this to be true always. A lot would have to be wrong with our notions of physics to have light “just lose energy.”

That seems like a perfectly natural solution. How do we know it isn’t true?

This solution requires light from distant galaxies to behave in ways totally different from every other physical process we know about—including physical processes in distant galaxies. It seems unnatural to say “the redshift is explained by a totally new physical process, and this process violates a lot of natural laws that hold everywhere else.”

[1] I should say, reversible assuming you also flip the charges and parities. That’s irrelevant here, though, since photons are uncharged and don’t have any special polarization.

asr 8 Jan 2015 22:16 UTC
2 points
in reply to: roystgnr’s comment on: Exams and Overfitting
Speaking as a former algorithms-and-complexity TA --

Proving something is in NP is usually trivial, but probably would be worth a point or two. The people taking complexity at a top-tier school have generally mastered the art of partial credit and know to write down anything plausibly relevant that occurs to them.

asr 8 Jan 2015 7:04 UTC
5 points
in reply to: buybuydandavis’s comment on: Some recent evidence against the Big Bang

What if it light just loses energy as it travels, so that the frequency shifts lower? That seems like a perfectly natural solution. How do we know it isn’t true?

As gjm mentions, the general name for this sort of theory is “tired light.” And these theories have been studied extensively and they are broken.

We have a very accurate, very well-tested theory that describes the way photons behave, quantum electrodynamics. It predicts that photons in the vacuum have a constant frequency and don’t suddenly vanish. Nor do photons have any sort of internal “clock” for how long they have been propagating. As near as I can tell, any sort of tired light model means giving up QED in fairly fundamental ways, and the evidentiary bar to overturn that theory is very high.

Worse, tired light seems to break local energy conservation. If photons just vanish or spontaneously redshift, where does the energy go?

I can conceive of there being a tired light model that isn’t ruled out by experiment, but I would like to see that theory before I junk all of 20th century cosmology and fundamental physics.

Most scientific theories, most of the time, have a whole bunch of quirky observations that they don’t explain well. Mostly these anomalies gradually go away as people find bugs in the experiments, or take into account various effects they hadn’t considered. The astronomical anomalies you point to don’t seem remotely problematic enough to give up on modern physics.

asr 24 Dec 2014 5:16 UTC
5 points
in reply to: Capla’s comment on: Open thread, Dec. 22 - Dec. 28, 2014
“Falling in love” isn’t this sudden thing that just happens, it’s a process and it’s a process that is assisted if the other person is encouraging and feels likewise. Put another way, when the object of your affection is uninterested, that’s often a turnoff, and so one then looks elsewhere.

asr 19 Dec 2014 6:06 UTC
0 points
on: Entropy and Temperature
There is a peculiar consequence of this, pointed out by Cosma Shalizi. Suppose we have a deterministic physical system S, and we observe this system carefully over time. We are steadily gaining information about its microstates, and therefore by this definition, its entropy should be decreasing.

You might say, “the system isn’t closed, because it is being observed.” But consider the system “S plus the observer.” Saying that entropy is nondecreasing over time seems to require that the observer is in doubt about its own microstates. What does that mean?

asr 4 Dec 2014 4:19 UTC
0 points
on: Stuart Russell: AI value alignment problem must be an “intrinsic part” of the field’s mainstream agenda
Russell is an entirely respectable and mainstream researcher, at one of the top CS departments. It’s striking that he’s now basically articulating something pretty close to the MIRI view. Can somebody comment on whether Russell has personally interacted with MIRI?

If MIRI’s work played a role in convincing people like Russell, that seems like an major accomplishment and demonstration that they have arrived as part of the academic research community. If Russell came to that conclusion on his own, MIRI should still get a fair bit of praise for getting there first and saying it before it was respectable.

In either case, my congratulations to the folks at MIRI and I will up my credence in them, going forwards. (They’ve been rising steadily in my estimation for the last several years; this is just one of the more dramatic bumps.)

asr 31 Oct 2014 0:19 UTC
34 points
on: 2014 Less Wrong Census/Survey
Did the survey. Mischief managed.

asr 19 Sep 2014 18:16 UTC
8 points
in reply to: NxGenSentience’s comment on: Superintelligence Reading Group—Section 1: Past Developments and Present Capabilities

Did you read about Google’s partnership with NASA and UCSD to build a quantum computer of 1000 qubits?

Technologically exciting, but … imagine a world without encryption. As if all locks and keys on all houses, cars, banks, nuclear vaults, whatever, disappeared, only incomparably more consequential.

My understanding is that quantum computers are known to be able to break RSA and elliptic-curve-based public-key crypto systems. They are not known to be able to break arbitrary symmetric-key ciphers or hash functions. You can do a lot with symmetric-key systems—Kerberos doesn’t require public-key authentication. And you can sign things with Merkle signatures.

There are also a number of candidate public-key cryptosystems that are believed secure against quantum attacks.

So I think we shouldn’t be too apocalyptic here.

asr 26 Aug 2014 20:45 UTC
5 points
on: [LINK] Could a Quantum Computer Have Subjective Experience?
Taking up on the “level above mine” comments—Scott is a very talented and successful researcher. He also has tenure and can work on what he likes. The fact that he considers this sort of philosophical investigation worth his time and attention makes me upwardly revise my impression of how worthwhile the topic is.

asr 18 Aug 2014 2:32 UTC
5 points
in reply to: James_Miller’s comment on: [meta] Future moderation and investigation of downvote abuse cases, or, I don’t want to deal with this stuff
Points 1 and 2 are reasonably clear. Point 3 is unhelpfully vague. If I were moderator, I would have no idea how far that pushes, and as a commenter I wouldn’t have a lot of insight as to what to avoid.

I don’t mind giving a catch-all authority to a moderator, but if there are specific things you have in mind that are to be avoided, it’s probably better to enumerate them.

I would add an explicit “nothing illegal, nothing personally threatening” clause. Those haven’t been problems, but it seems better to remind people and to make clear we all agree on that as a standard.

asr 1 Aug 2014 19:46 UTC
0 points
in reply to: Mark_Friedenbach’s comment on: Saving the World—Progress Report
Interesting. Can you say more about how your work compares to existing VMs, such as the JVM, and what sorts of things you want to prove about executions?