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Brian Slesinsky
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Brian Slesinsky

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Logic hacking

In mathematics, unlike ordinary life, the boundary between the knowable and the unknowable is a precisely defined thing.   But finding it isn't easy.  Its exact location could itself  be unknowable.  But we don't even know that! 

This month, a bunch of 'logic hackers' have stepped up to the plate and made a lot of progress.  They've sharpened our estimate of where this boundary lies.  How?   By writing shorter and shorter computer programs for which it's unknowable whether these programs run forever, or stop.

A Turing machine is a simple kind of computer whose inner workings have N different states, for some number N = 1,2,3,...

The Busy Beaver Game is to look for the Turing machine with N states that runs as long as possible before stopping.  Machines that never stop are not allowed in this game. 

We know the winner of the Busy Beaver Game for N = 1,2,3 and 4.  Already for N = 5, the winner is unknown.  The best known contestant is a machine that runs for 47,176,870 steps before stopping.  There are 43 machines that might or might not stop - we don't know. 

When N is large enough, the winner of the Busy Beaver Game is unknowable

More precisely, if you use the ordinary axioms of mathematics, it's impossible to prove that any particular machine with N states is the winner of the Busy Beaver Game... as long as those axioms are consistent.

How big must N be, before we hit this wall?

We don't know. 

But earlier this month, Adam Yedidia and Scott Aaronson showed that it's 7910 or less. 

And by now, thanks to a group of logic hackers like Stefan O’Rear, we know it's 1919 or less. 

So, the unknowable kicks in - the winner of the Busy Beaver Game for N-state Turing machines becomes unknowable using ordinary math - somewhere between N = 5 and N = 1919. 

The story of how we got here is is fascinating, and you can read about it on my blog post:

https://johncarlosbaez.wordpress.com/2016/05/21/the-busy-beaver-game/

Anything that I didn't make clear here, should be explained there.  If it ain't clear there, ask me!

#bigness  
This month, a bunch of ‘logic hackers’ have been seeking to determine the precise boundary between the knowable and the unknowable. The challenge has been around for a long time. But on…
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From the article: "Meanwhile, ten thousand drivers are out of a job—or at least a second job. The city’s huge phalanx of former ride-sharing drivers finds itself scrambling for work. The city responded by setting up a useless hotline and a “job fair” that consisted of little more than telling people how to apply for expensive chauffeur’s licenses and cab medallions. Most people can’t afford those, so instead drivers are offering their services on hastily assembled underground Facebook ride-sharing communities, marketing themselves in the same way a freelance handyman or pool-repair guy would. And desperate riders are responding."
In the aftermath of Austin's rideshare vote, a disaster of price gouging, traffic and bad taxis.
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Rent a car, call a cab, or just skip travelling to cities with poor transportation.

I assume the short-term hassles will be worked out as other companies fill the gap, but also wouldn't be surprised if tourism goes down in some places in Austin as travel becomes less convenient.
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05.14.2016 · Shuffleboard At McMurdo. Somewhere below the Antarctic circle, I catch Tatiana, the waitress from the port side dining room, in a moment of leisure. This is the first time I've ever seen her off-duty. The galley crew on the Akademik Shokalskiy work twelve-hour days preparing, ...
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"Like bacon bits scraped off a griddle, space rocks accumulate at glacier edges and make life a breeze for collectors, except for the part where they have to come to Antarctica." -- including bits of Mars and the Moon.
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From the article: "The elephants reacted so strongly, the researchers believe, because drones, it turns out, sound a lot like bees. And elephants do not like bees. At all."
Researchers from Duke tried to use unmanned aerial vehicles to track a herd’s behavior. Things did not go as planned.
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Only about one-quarter of U.S. corporate stock is held in taxable accounts, far less than most researchers and policymakers thought.
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From the bug: "On Windows, this results in kernel memory corruption, as the scan engine is loaded into the kernel (wtf!!!), making this a remote ring0 memory corruption vulnerability - this is about as bad as it can possibly get."
@taviso @SwiftOnSecurity @DrPizza It's funny how few realize that AV software can be vulnerable. Native code pointed at untrusted data... Tavis Ormandy · May 16. Tavis Ormandy @taviso. @SwiftOnSecurity dunno what you mean, I give a lot of fucks, that's why we work on this stuff.
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From the article: "Then, starting in the sixties, along came therapies like cognitive behavioral therapy, in which you were encouraged instead to get in the ring and fight with your thoughts. You think your mother never liked you? Never? Really? Doesn’t that sound like a bit of an overgeneralization? Aren’t you putting too much faith in your ability to know the contents of another person’s mind? Now, we treat our thoughts even more disrespectfully, like the blather of the overhead TVs at the airport. Rather than fact check every claim, or scrutinize every contributor for bias, we can, with the assurance that most of what’s being broadcast is sensationalistic garbage, proceed toward our designated gate."
A brief history of being wrong.
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One of my favorite books ever is Being Wrong: Adventures in the Margin of Error.
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From the article: "the hobbyist beekeeper had removed the hive, which left the aggressive bees roaming the neighborhood with nowhere to go."
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I decided to more accurately predict the next move instead of depending on my instincts, and I am putting that into practice.Lee Se-dol (9-dan, 33···
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The oil change itself seemed okay, but it seemed understaffed (two people), and they were fairly unhelpful. Nobody talked to the customers when they arrived. Waited a long time to pay after the oil change was done, while they both worked on another car. The maintenance light wasn't reset so I went back, and after waiting for a while I ended up looking up in the manual how to reset it myself.
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We eat here often. The garlic noodles are very tasty.
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They moved to Mountain View at 2500 El Camino Real, on the corner opposite Whole Foods and Target. Other than that, smooth transaction; they took a carload of old electronics and didn't seem too picky.
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Smooth transaction; rented a cargo van Saturday afternoon, returned that night (after hours). Actual cost: $30 + $42 mileage + $35 fuel + $7 taxes = $114 for 53 miles.
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