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A few weeks ago, I was asked a very good question: Is there a good introduction to the ideas of AI for someone who isn't an engineer, and doesn't want to be one, but who wants to be able to intelligently discuss the social and ethical issues around it?

I couldn't find any answer to that question which I liked, so I sat down to write one. So here's my answer, in long form: both about the basics of what AI is and can and can't do, and about several examples of real social and ethical challenges that AI has already run into, and how we can use these to start to reason about these problems in general.

(Yes, this one is members-only; if you haven't signed up for a Medium account yet, it's probably about time. The first few hits are free...)

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I'm not exactly sure which category this goes in, but it's something very deep and worth your time to read: About listening to people, and believing them, and being believed.

Via +A.V. Flox.

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Rice straw isn't used for things like tatami nearly as much as it used to be; those are more commonly made from plastic nowadays. And that means that, at the end of the rice harvest, there's a lot of extra straw left over.

There is only one solution to this problem: GIANT ANIMALS.

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For anyone who has been wondering about how guns work, or about the various claims being made in the media in the aftermath of the shooting in Las Vegas, I highly recommend you read +Robert Hansen's posts. He explains things clearly and from deep familiarity, and isn't trying to sell you an agenda in the process.

(I actually recommend reading him for a lot of other reasons, since he's very interesting, but this one is particularly relevant right now, as he's just made several posts on the subject)
Q: So what's bump fire, anyway?

A: A sign you're a lousy shooter.

Let's talk about how a firearm works for a moment. This is going to be at a very high level: you aren't going to need detailed mechanical knowledge to follow. Imagine a gun as a piece of pipe. A bullet gets loaded in at one end, is fired, and it comes out the other.

Now, the end the bullet is at needs to be locked down somehow to keep the case from coming free. Newton's Law of Equal and Opposite Reactions: if there's something pushing the bullet out of the barrel, it's also going to push the case out of the barrel. We don't want this to happen just yet, not until the bullet has completely left the barrel. So to keep the bullet in place, we have something called a bolt. The bolt can be thought of as sort of like an end-cap you screw on a piece of pipe: it closes the end and keeps the bullet in place.

In older rifles, the bolt gets opened and closed manually. You place your hand on the bolt handle, you manipulate the bolt, you open the pipe (barrel) and pull out the spent cartridge. A new cartridge is pushed up by a spring from an ammunition reservoir (a magazine) beneath the bolt. Then you close the bolt, and you're ready to fire once more.

Manually-operated rifles are great. They're tons of fun. But in the late 1800s, Hiram Maxim realized the energy of the bullet could be used to automatically open and close the bolt. You pull the trigger, the gun fires, and a small portion of the energy of the gunshot is used to open the action. A new bullet pops up from the reservoir, the action closes, and the gun fires again, and again, and again.

The first machinegun Hiram Maxim invented had a problem: once you started it, it couldn't stop. Oops. Once you started that process it would continue without end until the weapon ran out of ammunition. This turned out to be a simple problem to fix: Hiram Maxim invented the sear, which is basically a small metal lever. When you release the trigger, this small lever comes up and interferes with the automatic opening and closing of the bolt. Once you do that, the rhythm stops.

After Hiram Maxim had the fully automatic sear invented, the next step was to invent the semi-automatic sear: a sear which came up automatically after only one shot was fired. You pull the trigger and the weapon goes bang, opens the bolt, ejects the spent round, loads a fresh round, closes the bolt, and ... the sear gets in the way. You're ready to fire again, but you haven't yet, and you can't, not until you allow the trigger to come forward. Once the trigger comes forward, the trigger is in place to move the sear out of the way and allow the firing process to continue; but when the trigger is fully back, it's out of place and can't trip the sear.

So: what's the difference between a semiautomatic weapon and a fully automatic weapon?

In a word, the sear. Everything else is incidental.

Now you know enough about firearms to know how bump fire works. It'll be over soon, I promise.

When you pull the trigger, Newton's Law says that the bullet leaving the muzzle means the rifle has to be pushed back a little bit. This is called recoil. (Some people call it "kick". They shouldn't. The right word is recoil.) So if you pull the trigger back just enough to trip the sear, the entire firearm will be pushed back a minute fraction of an inch -- but your finger won't be, since it's not attached to the weapon. So the weapon recoils, but your finger doesn't. If you were to push the weapon forwards, the just-reset trigger will be pressed against your finger, and your finger will trip the trigger, and it'll go bang again.

Usually, bump fire is a sign you're a bad shooter. It means you don't have proper control over the weapon, or your trigger pull is way too light and cringing. (You want a firm, deliberate pull.) Bump fire from newbies isn't exactly common, but it's not unheard of, either.

A bump fire stock takes this defect of marksmanship and exploits it to mimic the effects of fully-automatic fire. A bump fire stock is effectively just a spring set at the end of the weapon's normal stock, with a plastic cover over the entire apparatus to make it not like the cheap piece of crap that it is.

You pull the trigger. The weapon recoils. The spring compresses. Then the spring expands, pushing the rifle forwards against your finger. The weapon fires. The weapon recoils. And so on and so on. And it's all technically legal, because the sear in your weapon is still semiautomatic.

Most shooters hate bump fire. It's inaccurate and it's expensive. Each time you pull the trigger you're sending anywhere between a quarter and two bucks downrange, depending on the quality of ammunition you use. A thirty-round magazine will last for about three seconds of bump fire. Spending anywhere from $10 to $60 for three seconds of fun is not my idea of a fun time.

It's also incredibly inaccurate. When your rifle is literally rocking back and forth in your hands by a quarter-inch ten times a second, you're going to have a hard time keeping it on target. Real fully-automatic weapons are designed to be relatively motionless under recoil: you lean forwards as the recoil pushes the rifle back, the rifle stays pointed at the target. But a bumpfire weapon is designed to move constantly under recoil, and that has really bad consequences for accuracy.

Anyway. That's what bump fire is and how it works. Now you know.

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+A.V. Flox wrote a beautiful, and illuminating, meditation on different ideals of femininity, the ways in which individual needs conflict with them, and how this was affected by the different legacies of Hugh Hefner. There's no short summary I can give of it, because it's fundamentally a piece about what isn't simple; so let me give you a quote from near its beginning, to give you a sense of its flavor.

It’s bad form for the firstborn to come into this world a girl, thus I suppose that was my very first rebellion. I was expected to mind my place, and so made a habit of taking the things denied me. A proper young lady must not, I was told, and rather than rebel against the very concept, I — with all the audacity of a seven-year-old — made it a part of myself. By personifying the proper young lady, I did, and therefore, I could.

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Sixty years ago today, at 22:28:34 Moscow time, 4 October 1957, an R-7 rocket carrying Sputnik-1 launched from Baikonur Cosmodrome, and the age of space began.

58 centimeters across, carrying a 1-watt transmitter which sent steady beeps at 20.005 and 40.002MHz for the next three weeks, the little ball was Earth's first artificial companion.

Happy 60th birthday, Sputnik!

Question: A reader recently asked me if I could offer a good recommendation for an intro to ML – not the technical aspects, but enough to give them a basis for understanding how it might affect society down the road.

While I know a lot of people who would be qualified to write such a thing, I don't know anyone who actually has written such a thing. But some of you might: does anyone know any good intro to current thinking in this space?

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+Tim Blais out with a new song today – and one of his best. Evolutionary and developmental biology.

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Sleep is one of the great mysteries of biology. It's obviously dangerous to do it – you're unaware of both predators and potential food going by – and yet it's been observed in everything down to roundworms, and without it, we die. Clearly it does something extremely important.

A discovery by three Caltech grad students adds another layer to this: Cassiopea jellyfish, also known as "upside-down jellyfish," sleep – even though they don't have brains at all, just a diffuse network of neurons. They show the same symptoms that more complex animals do: reversible quiescence (they can be woken up), increased arousal threshold, (they don't jump at things they would normally notice), and homeostatic regulation of sleep (they have trouble if they don't do it regularly).

Apparently, whatever sleep does, it's so basic to survival that even diffuse neural networks need to do it.

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I am sad to report that on May 19th, Stanislav Petrov, one of the great unsung heroes of our time, passed away at the age of 77.

In 1983, Petrov was a Lieutenant Colonel in the Soviet Air Defense Forces. On September 26th, at a time of particularly heightened tensions, he was duty officer in command of Serpukhov-15, the central command center for Soviet early warning satellites. Shortly after midnight, those satellites detected five incoming American ICBM's.

Petrov later said that the pattern of the attack made no sense to him – why would the Americans attack with only five missiles, instead of going all-out? – and so he unilaterally decided it must be a false alarm, and did not report it.

If you consider how risky it would be for a field officer to make such a decision in a normal army, consider what that meant in the USSR under Andropov: if he was wrong, and somehow survived the resulting nuclear war, and perhaps even if he was right and it embarrassed the wrong people, he could have found himself shot in the basement of Lubyanka.

As it was, he was questioned, alternately praised and condemned, and the entire incident ultimately buried until the publication of Yury Votintsev's (the then-commander of the Soviet missile system) memoirs in the 1990's. His own wife didn't know about it until over ten years later.

The 1983 incident was one of the closest points we have ever come to global nuclear annihilation. As later investigation showed, it was caused by an unexpected reflection of sunlight off high-altitude clouds when the satellites were in a particular part of their orbit – a perfectly reasonable sort of bug which, had anyone else been duty officer that day, could have led to the Soviet Union launching a thermonuclear war.

Petrov never considered himself a hero for what he did that day: he was just doing his job. I would say that, if we could all "just do our jobs" that well, our world would be a safer place.

Politics ensured that Petrov would never be formally commended (or even officially praised) for his actions, but if there was ever a man who deserved to be called a Hero of the Soviet Union, it was him.

Thank you, Stanislav Yevgrafovich, and farewell.
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