trentmkelly/LessWrong-43k huggingface dataset:
How to pick your categories
by  — 2010-11-11T15:13:58.511Z

Note: this is intended to be a friendly math post, so apologies to anyone for whom this is all old hat. I'm deliberately staying elementary for the benefit of people who are new to the ideas. There are no proofs: this is long enough as it is.

Related: Where to Draw the Boundary, The Cluster Structure of Thingspace, Disguised Queries.

Here's a rather deep problem in philosophy: how do we come up with categories? What's the difference between a horror movie and a science fiction movie? Or the difference between a bird and a mammal? Are there such things as "natural kinds," or are all such ideas arbitrary?

We can frame this in a slightly more mathematical way as follows. Objects in real life (animals, moving pictures, etc.) are enormously complicated and have many features and properties. You can think of this as a very high dimensional space, one dimension for each property, and each object having a value corresponding to each property. A grayscale picture, for example, has a color value for each pixel. A text document has a count for every word (the word "flamingo" might have been used 7 times, for instance.) A multiple-choice questionnaire has an answer for each question. Each object is a point in a high-dimensional featurespace. To identify which objects are similar to each other, we want to identify how close points are in featurespace. For example, two pictures that only differ at one pixel should turn out to be similar.

We could then start to form categories if the objects form empirical clusters in featurespace. If some animals have wings and hollow bones and feathers, and some animals have none of those things but give milk and bear live young, it makes sense to distinguish birds from mammals. If empirical clusters actually exist, then there's nothing arbitrary about the choice of categories -- the categories are appropriate to the data!

There are a number of mathematical techniques for assigning categories; all of them are basically attacking the same problem, and in principle should all agree with each other and identify the "right" categories. But in practice they have different strengths and weaknesses, in computational efficiency, robustness to noise, and ability to classify accurately. This field is incredibly useful -- this is how computers do image...
[LINK] Creationism = High Carb? Or, The Devil Does Atkins
by Nic_Smith — 2010-11-11T03:41:06.707Z

Based on the community's continuing interests in diet and religion, I'd like to point out this blog post by the coauthor of Protein Power, Michael Eades, wherein he suggests that biblical literalism tends toward a low-fat approach to nutrition over a low-carb philosophy, by essentially throwing out a bunch of evidence on the matter:

Why, you might ask, is this scientist so obdurate in the face of all the evidence that’s out there? Perhaps because much of the evidence isn’t in accord with his religious beliefs. I try never to mention a person’s religious faith, but when it impacts his scientific thinking it at least needs to be made known. Unless he’s changed his thinking recently, Dr. Eckel apparently is one of the few academic scientists who are literal interpreters of the bible. I assume this because Dr. Eckel serves on the technical advisory board of the Institution for Creation Research, an organization that believes that not only is the earth only a few thousand years old , but that the entire universe in only a few thousand years old. And they believe that man was basically hand formed by God on the sixth day of creation. And Dr. Eckel’s own writings on the subject appear to confirm his beliefs

[.....]

Of all the evidence that exists, I think the evolutionary/natural selection data and the anthropological data are the most compelling because they provide the largest amount of evidence over the longest time. To Dr. Eckel, however, these data aren’t applicable because in his worldview prehistoric man didn’t exist and therefore wasn’t available to be molded by the forces of natural selection. I haven’t a clue as to what he thinks the fossil remains of early humans really were or where they came from. Perhaps he believes – as I once had it explained to me by a religious fundamentalist – these fossilized remains of dinosaurs, extinct ancient birds and mammals and prehistoric man were carefully buried by the devil to snare the unwary and the unbeliever. If this is the case, I guess I’ll have to consider myself snared.

In Dr. Eckel’s view, man was created post agriculturally. In fact, in his view, there was never an pre-agricultural era, so how could man have failed to adapt to agriculture?

&n

...
Pet Cryonics
by Jack — 2010-11-11T00:13:18.011Z

Open discussion.

I think my dog is about to die. Even if I thought it was worth it I don't have the money to freeze her. But I am curious to know how people here feel about the practice and whether anyone plans to do this for their pet. It seems like a practice that plays into the image of cryonics as the domain of strange and egotistical rich people. On the other hand it also seems like a rather human and heart warming practice. Is pet cryopreservation good for the image of cryonics?

Also, do people who just do neuro get their pets preserved? Will people upload pets? Assuming life as an emulation feels different from life as a biological organism is it ethical to upload animals? The transition might be strange and uncomfortable but we expect at least some humans to take the risk and live with any differences. But animals don't understand this and might not have the mental flexibility to adjust.
SIA says AI is no big threat
by KatjaGrace — 2010-11-10T22:00:32.000Z

Artificial Intelligence could explode in power and leave the direct control of humans in the next century or so. It may then move on to optimize the reachable universe to its goals. Some think this sequence of events likely.

If this occurred, it would constitute an instance of our star passing the entire Great Filter. If we should cause such an intelligence explosion then, we are the first civilization in roughly the past light cone to be in such a position. If anyone else had been in this position, our part of the universe would already be optimized, which it arguably doesn’t appear to be. This means that if there is a big (optimizing much of the reachable universe) AI explosion in our future, the entire strength of the Great Filter is in steps before us.

This means a big AI explosion is less likely after considering the strength of the Great Filter, and much less likely if one uses the Self Indication Assumption (SIA).

The large minimum total filter strength contained in the Great Filter is evidence for larger filters in the past and in the future. This means evidence against the big AI explosion scenario, which requires that the future filter is tiny.

SIA implies that we are unlikely to give rise to an intelligence explosion for similar reasons, but probably much more strongly. As I pointed out before, SIA says that future filters are much more likely to be large than small. This is easy to see in the case of AI explosions. Recall that SIA increases the chances of hypotheses where there are more people in our present situation. If we precede an AI explosion, there is only one civilization in our situation, rather than potentially many if we do not. Thus the AI hypothesis is disfavored (by a factor the size of the extra filter it requires before us).

What the Self Sampling Assumption (SSA), an alternative principle to SIA, says depends on the reference class. If the reference class includes AIs, then we should strongly not anticipate such an AI explosion. If it does not, then we strongly should (by the doomsday argument). These are both basically due to the Doomsday Argument.

In summary, if you begin with some uncertainty about whether we precede an AI explosion, then updating on the observed large total filter and accepting SIA should make you much less confident in that outcome. The Great Filter and SIA don’t just mean that we are less likely to p...
What does it mean to optimize future?
by red75 — 2010-11-10T15:43:23.326Z

Preamble

Value deathism by Vladimir Nesov encourages us to fix our values to prevent astronomical waste due to under-optimized future.

When I've read it I found that I think about units of measurement of mentioned astronomical waste. Utilons? Seems so. [edit] Jack suggested widely accepted word Utils instead.[/edit]

I've tried to precisely define it. It is difference between utility of some world-state G measured by original (drifting) agent and utility of world-state G measured by undrifting version of original agent, where world-state G is optimal according to original (drifting) agent.

There are two questions: can we compare utilities of those agents and what does it mean that G is optimal?

Question

Preconditions: world is deterministic, the agent has full knowledge of the world, i.e. it knows current world-state, full list of actions available for every world-state and consequence of each action (world-state it leads to), the agent has no time limit for computing next action.

Agent's value is defined as a function from set of world-states to real numbers, for the sake of, uhm, clarity, the bigger the better. (Note: it is unnecessary to define value as a function from set of sequences of world-states, as history of world can be deduced from world-state itself, and if it can't be deduced, then the agent can't use history anyway, as the agent is a part of this world-state, so it doesn't "remember" history too). [edit] I wasn't aware that this note includes hidden assumption: value of world-state must be constant. But this assumption doesn't allow agent to single out world-state where agent loses all or part of its memory. Thus value as a function over sequences of world-states has a right to be. But this value function still needs to be specifically shaped to be optimization algorithm independent. [/edit]

Which sequence of world-states is optimal according to agent's value?

Edit: Consider agents implementing greedy search algorithm and exhaustive search algorithm. For them to choose same sequence of world-states search space should be greedoid. And that requires very specific structure of value function.

Edit2: Alternatively value function can be indirectly self-referential via part of world-state that contains the agent, thus allowing it to modify agent's optimization algorithm by assigning higher utility to world-states w...
Description complexity: an apology and note on terminology
by cousin_it — 2010-11-10T00:43:40.009Z

This post is an amendment and sort of apology for my LW posts dealing with complexity (1, 2). In these posts I got the terms all wrong. Now I'll try to set it right. Many thanks to taw, JGWeissman and Daniel_Burfoot.

The Solomonoff prior works like this: every bit string is assigned a real number that's equal to the probability of a "random program" outputting that string and then halting, when the "probability" of choosing each program is assumed to be inverse-exponential in its length. (Alternatively, you talk about a "universal prefix Turing machine" that consumes fair coin flips on the input tape.)

In this setup, the words "event", "hypothesis", "probability", "complexity" etc. are all ambiguous. For example, the word "hypothesis" can mean a) an individual program, b) an equivalence class of programs that output the same bit string, or c) a statement about output bit strings, like "the third bit will be 0". The word "event" has exactly the same problem.

Now the trouble is, you can give reasonable-sounding definitions of "probability" and "Kolmogorov complexity" to objects of all three types: (a), (b), and (c). But it's not at all clear what real-world implications these values should have. Does it make sense to talk about prior probability for objects of type (a), given that we can never distinguish two (a)'s that are part of the same (b)? (This is the mistake in saying that MWI has a higher prior probability than collapse interpretations.) Is it useful to talk about K-complexity for objects of type (c), given that a very long statement of type (c) can still have probability close to 1? (This is the mistake in saying Islam must be improbable because the Qur'an is such a thick book.) For that matter, is it at all useful to talk about K-complexity for objects of type (b) which are after all just bit strings, or should we restrict ourselves to talking about their prior probabilities for some reason?

At the moment it seems uncontroversial that we can talk about K-complexity for objects of type (a) - let's call them "programs" - and talk about prior probability for objects of types (b) and (c) - let's call them "sequences of observations" and "statements about the world", respectively. Curiously, this means there's no object for which we have defined both "complexity" and "prior probability", which makes all arguments of the form "complexity is high => probabi...
Cryoburn - Imperial Auditor Vorkosigan investigates the cryonics industry
by Perplexed — 2010-11-09T21:16:42.808Z

I just completed "Cryoburn", Lois McMaster Bujold's latest novel in the Vokosigan Saga series. The subject is cryonics.

Our hero Miles is dispatched to the planet Kibou-daini to investigate the cryonics industry there. A Kibou company is planning to expand its business to Komarr, and Miles's Komar-born empress is supicious of financial chicanery. Miles himself has undergone freezing (military medical emergency) and more-or-less-successful revival, but the notion of geriatric cryonics is a topic not previously explored in Bujold's universe. It is explored reasonably well here.

Although some of the cryonics companies in this book are corrupt, Bujold's take on cryonics is mostly positive. She is very much in sympathy with the human desire for immortality or at least serious life extension. But she points out and explores some practical problems. Revival is not a problem in this book. That one is pretty much solved. But cryonics is not a cure for old age, it is at best a way of allowing more time for a cure to be found. Naq pbairavragyl, gur Qheban tebhc frrzf gb unir pbzr hc jvgu n erwhirangvba gerngzrag (jryy, abg rknpgyl erwhirangvba - zber yvxr er-zvqqyr-ntr-vsvpngvba). Ohg gur gerngzrag vf abg lrg grfgrq, naq ZIX Ragrecevfrf vf pbafvqrevat gur chepunfr bs n jnerubhfr shyy bs sebmra cnhcref nf n cbgragvny fbhepr bs grfg fhowrpgf.

Another problem explored is political. On Kibou, people are generally frozen before death, so as to maximize the chances of a successful revival. So, since they are not really dead, they still can own property (in trust) and they still have the right to vote (by proxy). The cryonics companies hold those proxies and control those trusts and hence have political and economic control of the planet. And of course, they don't particularly want to revive their clients and give up that control.

And then there are technological problems. Vg gheaf bhg gung bar oenaq bs pelbavp syhvq (oybbq-fhofgvghgr/nagvserrmr) juvpu jnf jvqryl hfrq n srj qrpnqrf ntb unf fbzr fgnovyvgl ceboyrzf. Juvpu zrnaf gung n pbhcyr zvyyvba bs gur cynarg'f uhaqerqf bs zvyyvbaf bs sebmra pbecfrf ner arire tbvat gb jnxr hc. Ubj qbrf gur pbzcnal vaibyirq qrny jvgu gur ceboyrz? Uvag: ubj qvq Nzrevpna onaxf qrny jvgu gur zvyyvbaf bs zbegtntrf gurl uryq gung jb...
Know thyself vs. know one another
by KatjaGrace — 2010-11-09T20:40:02.000Z

People often aspire to the ideal of honesty, implicitly including both honesty to themselves and honesty with others. Those who care about it a lot often aim to be as honest as they can bring themselves to be, across circumstances. If the aim is to get correct information to yourself and other people however, I think this approach isn’t the greatest.

There is probably a trade off between being honest with yourself and honest to others, so trying hard to be honest to others only detriments being honest to yourself, which in turn also prevents correct information getting to others.

Why would there be a trade off? Imagine your friend said, ‘I promise that anything you tell me I will repeat to anyone who asks’. How honest would you be with that friend? If you say to yourself that you will report your thoughts to others, why wouldn’t the same effect apply?

Progress in forcing yourself to be honest to others must be somewhat an impediment to being honest to yourself. Being honest with yourself is presumably also a disincentive to your being honest with others later, but that is less of a cost, since if you are dishonest with yourself you are presumably deceiving them about those topics either way.

For example imagine you are wondering what you really think of your friend Errol’s art. If you are committed to truthfully admitting whatever the answer is to Errol or your other friends, it will be pretty tempting to sincerely interpret whatever experience you are having as ‘liking Errol’s art’. This way both you and the others come off deceived. If you were committed to lying in such circumstances, you would at least have the freedom to find out the truth yourself. This seems like the superior option for the truth-loving honesty enthusiast.

This argument relies on the assumptions that you can’t fully consciously control how deluded you are about the contents of your brain, and that the unconscious parts of your mind that control this respond to incentives. These things both seem true to me.
A note on the description complexity of physical theories
by cousin_it — 2010-11-09T16:25:21.186Z

Followup to: The prior of a hypothesis does not depend on its complexity

Eliezer wrote:

In physics, you can get absolutely clear-cut issues. Not in the sense that the issues are trivial to explain. [...] But when I say "macroscopic decoherence is simpler than collapse" it is actually strict simplicity; you could write the two hypotheses out as computer programs and count the lines of code.

Every once in a while I come across some belief in my mind that clearly originated from someone smart, like Eliezer, and stayed unexamined because after you hear and check 100 correct statements from someone, you're not about to check the 101st quite as thoroughly. The above quote is one of those beliefs. In this post I'll try to look at it closer and see what it really means.

Imagine you have a physical theory, expressed as a computer program that generates predictions. A natural way to define the Kolmogorov complexity of that theory is to find the length of the shortest computer program that generates your program, as a string of bits. Under this very natural definition, the many-worlds interpretation of quantum mechanics is almost certainly simpler than the Copenhagen interpretation.

But imagine you refactor your prediction-generating program and make it shorter; does this mean the physical theory has become simpler? Note that after some innocuous refactorings of a program expressing some physical theory in a recognizable form, you may end up with a program that expresses a different set of physical concepts. For example, if you take a program that calculates classical mechanics in the Lagrangian formalism, and apply multiple behavior-preserving changes, you may end up with a program whose internal structures look distinctly Hamiltonian.

Therein lies the rub. Do we really want a definition of "complexity of physical theories" that tells apart theories making the same predictions? If our formalism says Hamiltonian mechanics has a higher prior probability than Lagrangian mechanics, which is demonstrably mathematically equivalent to it, something's gone horribly wrong somewhere. And do we even want to define "complexity" for physical theories that don't make any predictions at all, like "glarble flargle" or "there's a cake just outside the universe"?

At this point, the required fix to our original definition should be obvious: cut out the middle...
Bye Bye Benton: November Less Wrong Meetup
by Jasen — 2010-11-09T05:35:05.641Z

As some of you may know, SIAI is in the process of moving our Visiting Fellows Program to a larger and more permanent location in Berkeley. Nothing is final yet but, however things turn out, November will be the last month we spend at 3755 Benton street. In honor of the house's proud history, we'll be throwing one final Less Wrong meetup this Saturday, the 13th of November, starting at 6pm. Come meet the SingInst staff, the visiting fellows and your fellow Less Wrong readers for one final party in Santa Clara!

As usual, food and drink shall be provided.

Please RSVP at the meetup.com page if you plan to attend.
Recent results on lower bounds in circuit complexity. 
by JoshuaZ — 2010-11-09T05:02:50.842Z

There's a new paper which substantially improves lower bounds for circuit complexity. The paper, by Ryan Williams, proves that NEXP does not have ACC circuits of third-exponential size.

This is a somewhat technical result (and I haven't read the proof yet), but there's a summary of what this implies at Scott Aaronson's blog. The main upshot is that this is a substantial improvement over prior circuit complexity bounds. This is relevant since circuit complexity bounds look to be one of the most promising methods to potentially show that P != NP. These results make circuit complexity bounds be still very far off from showing that. But this result looks like it in some ways might get around the relativization barrier and natural proof barriers which are major barriers to resolving P ?=NP.
A hypothetical candidate walks into a hypothetical job interview...
by AngryParsley — 2010-11-09T04:13:55.592Z

Let's say you are interviewing a candidate for a job. In casual conversation, the candidate mentions that he is a member of a rather old and prestigious country club. You've never heard the name of the club before.

You look up the country club afterwards, and are surprised by what you read. The club refuses membership to homosexuals. It revokes the membership of couples who use birth control. Leadership positions are reserved to unmarried males.

The candidate is otherwise competent. Under what conditions would you hire him? Would you want a law passed banning hiring discrimination based on country club membership?

(The country club is analogous to a nicer version of the Catholic church. I left out a couple bad things.)

Religious discrimination is illegal in many parts of the world, and I think that's probably a good thing. Still, keeping this at the object level (no meta-rules or veils of ignorance) it seems to me that discriminating against religious people is fine. I'm curious what other people think.
The value of preserving reality
by lukstafi — 2010-11-08T23:51:17.130Z

A comment to http://singinst.org/blog/2010/10/27/presentation-by-joshua-foxcarl-shulman-at-ecap-2010-super-intelligence-does-not-imply-benevolence/: Given as in the naive reinforcement learning framework (and that can approximate some more complex notions of value) that the value is in the environment, you don't want to be too hasty with the environment lest you destroy a higher value you haven't yet discovered! So you especially wouldn't replace high complexity systems like humans with low entropy systems like computer chips, without first analyzing them.
Chicago Meetup 11/14
by steven0461 — 2010-11-08T23:30:49.015Z

Airedale and I will host a meetup this Sunday, starting 5 pm, in the Elephant & Castle Pub and Restaurant on 111 West Adams Street. We'll put up a sign saying "LessWrong".

We're open to changing the time or venue, so check back here to be sure, or join our Google Group for future updates. Having the meetup in the Loop seemed the best compromise, but we haven't tried this particular venue before and maybe someone has a better idea.