ealloc

Hold on. Why do so many civil liberty proponents such as yourself insist on dismissing and trivializing the Trayvon Martin case?

Isn't it possible to care about both racism and wiretapping/drones/secrecy a the same time?

Isn't racism one of the most serious issues in the US?

Why are you so sure any riots were 'incited by the media', rather than an autonomous response from the many people directly affected by racism?

Interestingly, Roosevelt wasn't elected in his first term and only became president because McKinley was assasinated.

Would he have been able to run on his own at that point? I suspect not - he would have been viewed as too progressive by the people in charge.

I wouldn't say the rule of law is an illusion - it's a social construct or a social tradition. The rule of law has had real power in the past, and has often given the minority power over the majority.

The problem is that as a social construct, it will break down if too few people believe in it. And that's what is starting to happen here.

The rule of law is pretty similar to money actually - it only has power if people believe it has power.

It's also a straw man argument. Nobody ever claimed voice recordings were collected, all news sources were very clear about that. He's just distracting from the actual complaint, which is that all of the other data is collected.

I never said you couldn't criticise islam. In fact, I think Islam is terrible and deserves criticism and mockery.

However, it is also true that many Muslim people are unjustly persecuted, and randomly bringing up that "their prophet had a 9 year old wife" fits into the pattern of discrimination. People who bring that up are either bigots who enjoy namecalling at Muslims, or people who are unaware of that social context of their words, which is a form of racism/privilege itself.

So, feel free criticise Islam (including for the 9 year old bride), but don't randomly bring it up if it's only vaguely related to the topic of discussion.

This type of racism carried out by people who are too lazy to realize they are hurting other people by their social blindness. It has to do with being oblivious to social context, due to one's priviledge.

The subject of Mohammed's child bride is frequently used to justify hate against muslims, and has a social context of islamophobia. If there weren't that social context it would be fine to bring it up randomly, but since there is, bringing it up is offensive. It's part of the discriminatory pattern muslims experience.

This is definitely a "Just So" scientific story. That is, it is an unverifiable account of why things might have happened. They used to be common in evolutionary thought until it became clear they were often wrong.

Just so stories can be thought provoking, but I'd prefer it if people writing them made it clear what they are, since they can often lead to muddled ideas rather than clarity. The tone of this article bugged me a little.

I've also heard this story before, and if you google you will see there are many alternative explanations, for example that red paint was chosen because it is a fungicide rather than because it was most plentiful. Why add any pigment at all, if cost is the issue?

Quoting the number of gun accidents is misleading. The point of a license is to keep dangerous equipment out of the hands of people who are a danger to others or themselves. Thus you should really count murder/suicide too, and as wikipedia says, "In 2010, there were 19,392 firearm-related suicide deaths, and 11,078 firearm-related homicide deaths in the United States". So guns really are at least as dangerous as cars, probably moreso since only 1/3 of households own guns.

oops you're right. Nevertheless, he clearly intends to extend rather than replace floating point since one of the goals is to estimate the errors in the floating point calculations, and he rounds.

He want more than compile-time simplification. He wants runtime simplification depending on the values encountered at runtime. For example in the quadratic equation.

And, he clearly isn't marketing it as a replacement for floating point. He says: "It is important to note, however, that the goal of the project is to make tools for symbolic calculations, not to create a viable alternative to the floating point." and he talks a lot about estimating numerical error and precision.

At some point you _do_ have to use floating point (the whole point of numeric computations is to do things you can't do symbolically), however, this project might enable judicous use of symbolic manipulation in coordination with floating point. Holding off the computation until further in the program might have advantages: Automatic reordering of computations to help preserve precision, automatic symbolic manipulation to cancel out large terms, and perhaps automatic calculation of the amount of precision needed (eg if calculating "a < b", generate the digits of a and b until they differ). The programmer could specify exactly when symbolic manipulation is desired vs numeric.

The quadratic equation case he shows is pretty good. Say you want to solve ax^2 + bx + c = 0. In C you might write "(-b + sqrt(b * b - 4 * a * c))/(2 * a)" which has all the precision problems he described. However, in his library that code would be converted to an AST, then symbolically simplified given the variable values, and _then_ evaluted numerically. The intermediate symbolic step would be able to automatically account for the edge cases, eg if c was 0, so that the numeric step wouldn't fail. In this case, the symbolic solver would recognize that (+, (sqrt, (-, ( *, b, b), 0)), b) is exactly zero before the floating point computation occurs.

I often write scientific programs with the issues he describes, and I have also wished for something along these lines but kind of suspect it is impossible. I usually have to play in mathematica/on paper a bit before finding an algorithm that takes care of the numeric issues (yes, even when using multiprecision), and while it would be nice for it to happen automatically, my impression is that the algorithms I find on paper are nontrivial for a computer to come up with. In some cases, however, the computer could have done it for me. But I have a feeling that in the case precision becomes an issue, even if this library gets me 90% of the way, I would still want total manual control of how the calculations occur. But I still want him to try in case it works!

There are a number of these. The one I have been using lately is sympy - a pure python symbolic math library.

You may also be interested in the open source "sage mathematics", which is a frontend/interface to many different open-source symbolic solvers such as sympy, maxima, GAP, PARI, Singular, and octave.

They are not as good as mathematica currently, but can already do quite a lot.

Actually, wealth follows an exponential distribution for the lower 95% of individuals (by wealth) [1]. However, yes, it does follow a power law for the 5% richest.

[1] http://arxiv.org/abs/cond-mat/0103544

Exactly.

The actual interesting thing about this crystal is that the atoms will spontaneously start spinning as you remove energy from the system. Ie, in the ground state (the lowest energy state) the atoms are in motion. This is in contrast to all the physical systems we are familiar with where the ground state is motionless.

The reason it is called a 'time crystal' is that the ground state 'breaks symmetry' in time in the same way that a regular crystal 'breaks symmetry' in space - in the sense that if you translate the system in space, you do not usually get back its original state, unlike a gas. And, this symmetry breaking occurs as you cool the system. Crystals self-organize in a periodic grid as you cool them from the liquid state, just as this time crystal will set itself in periodic motion as you cool it.

One consequence of the symmetry breaking is that the atoms will have to move either clockwise, or counterclockwise, and will "randomly" choose one of the two.

Good summary. But I disagree with the author that immutable strings and ubiquitous hashes are merely unfortunate idioms of python - to me python is about simplicity, and those things are what make python conceptually simple. I don't have to worry about clobbered buffers, nor about datastructure semantics besides simple hashes.

as lcampbell said, the point of mining is actually to keep and confirm legitimate transactions. Mining needs to be a 'difficult' (but otherwise useless) problem like cryptographic hashing in order to make it difficult to fake transactions. Computations which might be useful in some other way are too easy - only cryptographic hashing is 'difficult' enough to stop the fakes.

It's kind of like captchas - a seemingly pointless pain in the ass on purpose to weed out the spam.

The rules governing bitcoin are maintained by consensus, and the bitcoin developers have a large sway on this consensus.

If the majority of people decided they didnt like the current rules (eg all the people complaining about bitcoin deflation) they could very well change them by simple agreement.

Currently bitcoin supply is inflationary because 25 bitcoins are created every 10 minutes, and a similar amount will be generated for decades.

True, this amount is set to decrease to 0 eventually. However, with some planning conceivably this could be changed, as long as the majority of bitcoin users agree it should be changed.

It may not be too late - the parameters controlling the deflation are independent of bitcoin's cryptosystem, and can (technically very easily) be changed and improved. I think Bitcoin's creator thought a deflationary policy would help generate initial support for bitcoin by encouraging people to become invested. Arguably, without a deflationary policy bitcoin would never have caught on as it has.

Probably the most practical way to actually change the policy is to create an alternate 'bitcoin-2' network with a better (inflationary) policy. You could even allow transactions from the old network into the new one thus allowing people to carry their wealth over. If everyone agreed it was better, it would happen. The challenge is more social than technical.

For now though, it doesn't matter since the current bitcoin 'fiscal policy' is fairly expansionary (bitcoins are still being generated) and will be for years, and anyway the effect of 'fiscal policy' on bitcoin value is currently dwarfed by the effects of speculation and the increasing demand for bitcoins.

It seems to me the oculus rift can accrately account for all head motion when you are standing still. There is no need for eye-tracking: All the rift has to do is detect all head bobbing & rotation, and update the view acocrdingly. Your eyes can still look around on the lcd screen.

What the rift _can't_ do is account for long term linear acceleration (eg in a car or walking around), it's true. If you had a large empty room to walk around in with the rift on, even this could be accounted for, however.

Bitcoin's fiscal policy is only one part of the whole bitcoin idea. It is possible to change the fiscal policy while keeping the rest of the crypto-based system.

The fiscal policy is controlled by two numbers which are chosen by 'consensus' among bitcoin users: The reward for mining a block, and the 'difficulty' of mining a block. You can always mine blocks in violation this consensus (eg reward yourself too much), it's just that no one will listen to you, and no one will accept the bitcoins you 'mined'. However, If everyone agreed to change how we choose these numbers, we could change the policy.

I'm pretty sure you could set up a 'bitcoin-2' network which would honor transactions from the original bitcoin network into the new network, yet have different algorithms for reward and difficulty. For now though, it doesn't matter since the current 'fiscal policy' is quite expansionary.

The book "Powering the Future" also argues fuel will always outperform batteries, pointing out that both fuel and batteries store chemical energy, and that chemical energy density is fundamentally contrained by physics:

Since all atoms are approximately the same size there is a limit to how many bonds/volume you can have, and since all chemical bonds are roughly the same amount of energy there's a limit on how much energy/volume you can store with chemical energy.

The book then argues that hydrocarbon fuels come very close to the ideal energy density, and have many other advantages over batteries (weight (they're formed with light elements), extremely safe byproducts CO2 H2O, simple ingredients).

The equivalent petition for Steve Heymann: https://petitions.whitehouse.gov/petition/fire-assistant-us-...

> Most of the DNA in the human genome is junk

This topic is still very controversial and I don't think the article should be citing it in this context.

It was only a few months ago that the ENCODE project released its first results claiming that 80% of the genome is "functional", and many scientists have noted that their definition of "functional" is much too broad. It includes any piece of DNA that becomes bound to protein at some time, while it is known that many proteins bind nonspecifically.

No. You can imagine the fabric of space being dragged into the black hole faster than the speed of light. Since nothing within spacetime can move faster than that, no signals can ever leave the event horizon.

It's like a swimmer going over a waterfall. The water is like spacetime being dragged towards the black hole, and the swimmer is an object moving within spacetime. If the waterfall is falling faster than the person can possibly swim, the person can never get back up the waterfall.

For more info on this "river model" of spacetime, see:

http://jila.colorado.edu/~ajsh/insidebh/waterfall.html

http://arxiv.org/abs/gr-qc/0411060

Relatedly: Since spacetime can "flow" faster than the speed of light, you might think this allows FTL travel. Indeed, this idea is called the "Alcubierre drive".

Fair enough, if it's just an analogy I agree it gives the right intuition.

To be clear, what really happened under MWI is that the wavefunction "branched" into two around the time you created the two particles, and the two branches spearated from each other in configuration space just as the two marbles in your analogy separated in physical space. When you did the measurement, you merely realized which branch you are in.

Where the analogy fails is that the probabilities in QM are inconsistent with there actually having been some hidden choice of marbles made beforehand.

What you are describing is a "hidden variable theory", but it has been shown (See "Bell's Theorem") such a theory cannot be true. QM is stranger than that.

Yes, I see why a repetition/pattern approach wouldn't work, but I'm proposing something else: That the file may be generated by an algorithm, in the way one generates the digits of pi using an algorithm.

It's similar to how if I suspected he had generated his random file with a mersenne twister I could simply guess his seed and reproduce the file from it. (Though, I realize now this is an NP-hard problem)

If you just have to decompress a single file, I don't see why this problem is impossible since you can tune your decompressor to that file.

For example, files containing the digits of pi or e will have a uniform distribution of bytes (and are therefore incompressible by exploiting redundancy) but it is very easy to write a "decompressor" for them as there is a simple algorithm to obtain these numbers.

Is there a simple algorithm for every possible number? Because then it just becomes a question of finding the algorithm that generates that number. My intuition tells me "yes" but that it may be very hard to find it. Plus, you don't need to find an algorithm for the whole file, just some subsection of it.

> If you do not care about music enough to seek it out (which is most people)

If most people don't care much about music, why should we as a society spend so much money supporting the music industry?

I view the music industry & pop music as an ephemeral buisness which took advantage of the particular technology & society present in the 20th century, in the same way that some species of animal might evolve to take advantage of some ecological niche that appeared as global climate changes and then dies out once that niche dissapears.