asr

asr's Comments

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.

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.

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.

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.

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.

Natural Selection of Government Systems

This graph would be more interesting and persuasive with a better caption.

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.

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?

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.

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.

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