Less Wrong is a community blog devoted to refining the art of human rationality. Please visit our About page for more information.

Comment author: zeldamagic 05 April 2015 06:41:33PM 0 points [-]
Comment author: sketerpot 05 April 2015 07:20:29PM *  4 points [-]

Ah. That web site throws out too many claims to investigate fully -- who has the time? -- but if you google around for a sampling of them you'll notice that they tend to crumble under scrutiny. The sections mentioning quantum mechanics are especially blatant: they're gibberish, total incoherent misuse of terminology.

EDIT: There's a sequence of articles called Mysterious Answers to Mysterious Questions which is relevant here. One that applies in particular is Fake Explanations, which could be summarized as "If you are equally good at explaining any outcome, you have zero knowledge." When people talk about "etheric worlds on different frequencies", or "energy vortices swirling faster than the speed of light on the earth plane", what does this predict? What, concretely, does it mean? If it can explain anything, then it predicts nothing.

Comment author: zeldamagic 05 April 2015 06:05:08PM 0 points [-]

I found a website that might have credible evidence for the afterlife and I wanted to post about it here so it can be checked by the experts. I want to find evidence for whether God exists or not using rational methods and I think this site will be very helpful. I'm only a teenager though so I think I need adult guidance. I know many people here are atheists and naturalists so I hope there isn't any bias since you've learned to overcome it.

Comment author: sketerpot 05 April 2015 06:29:15PM 1 point [-]

Did you mean to post a link here? I'm not seeing one.

Comment author: sixes_and_sevens 05 March 2015 06:57:29PM 3 points [-]

It's not quite correct, but you've broadly got the thrust of it.

When two different inputs produce the same output from a hashing function, this is called a hash collision. Finding collisions in the SHA256 hashing function is part of how bitcoin mining works. It is very computationally expensive (which is kind of the point, re: bitcoin mining), but it's certainly tractable to find some input that generates the same output as another one.

If you were to try and search the space of all possible inputs for MD5, you'd quickly(ish) find an input that collided with the Obama Werewolf input, but it'd be garbage. If you had some system for quickly and reliably generating comprehensible English sentences, and just searched that space, you'd probably find a comprehensible English sentence that collided with it, but it would almost certainly not be the Obama Werewolf sentence. It's worth noting that MD5 will take an input of any length, and the space of possible comprehensible English sentences of unbounded length is basically infinite.

For short snippets of text, it's hard to find two comprehensible English sentences that collide under MD5, but in the link gjm provides above, there's a method for forcing the MD5 hash of a PDF by exploiting how MD5 works. For this reason and others, if you're doing any cryptographic heavy lifting, you probably want to use something more robust than MD5.

Comment author: sketerpot 08 March 2015 05:45:34AM 0 points [-]

If you were to try and search the space of all possible inputs for MD5, you'd quickly(ish) find an input that collided with the Obama Werewolf input, but it'd be garbage.

Really? Last I checked, the best known preimage attack against MD5 was too slow to be practical. Finding collisions is drastically easier, though I don't know any method for doing it with arbitrary plain-text English sentences.

Comment author: alienist 21 February 2015 08:48:34PM 3 points [-]

Then again Eliezer has been imposing modern sexual attitudes on the Wizarding World, whether out of ignorance or a desire to be politically correct I'm not sure. In any case, I find it one of the most jarring aspects of the fic.

Comment author: sketerpot 22 February 2015 09:42:56PM 3 points [-]

Not just modern sexual attitudes, but specifically the sexual attitudes you see in the Harry Potter fanfiction community. And I'm sure it was meant to be jarring. Magical Britain's culture is subtly but deeply different from that of the muggle country that shares its borders; it would be profoundly weird if there were no surprises, no culture shock.

Comment author: Michelle_Z 16 February 2015 03:48:40AM 14 points [-]

Yes. But two minutes before that he was thinking of taking Cedric, and then we get a cut scene to him sneaking about in the hallway with Lesath. That implies that Cedric might still be in play, otherwise we probably would've gotten a short sentence or two on why he chose Lesath over Cedric.

Cedric, who may or may not have a time turner, could quite possibly show up.

Comment author: sketerpot 16 February 2015 07:06:42AM 12 points [-]

He's the Super Hufflepuff! He's taking all the electives, which is physically impossible without a Time Turner! He was mentioned right before Harry started making thorough off-screen preparations, and then conspicuously forgotten for the rest of the chapter! Dramatic logic dictates that he's got to show up at some point, probably in some way that involves time travel.

... Unless the whole thing was a throwaway joke about how useless Cedric was in Goblet of Fire, in which case yeah, I guess it was pretty funny.

Comment author: vericrat 16 February 2015 05:04:38AM 2 points [-]

I think Solipsist was trying to say that if Voldemort using Sprout to cast a spell counts as originating from Voldemort, then if Sprout (or some other Imperiused individual) cast a spell on the troll's skin, then Harry shouldn't have been able to touch the troll. Before, it was assumed that Harry was able to touch the enchanted troll (its skin had been enchanted to resist sunlight) because Voldemort hadn't directly enchanted it (Harry can't touch things Voldemort enchants, see the broomstick escape from Azkaban) but used an Imperiused confederate. Now, however, it seems that using the Imperiused confederate does not negate the issues arising between Harry and Voldemort's magic.

Comment author: sketerpot 16 February 2015 06:57:10AM 13 points [-]

An alternate interpretation is that Voldemort was strengthening a few of the spells that Sprout cast, as well as the spell that Tonks used to win the battle, and this use of his own magic was what caused Harry's doom-sense to tingle. If that's the case, then there would be none of his magic on the troll.

Comment author: palladias 09 February 2015 04:32:04PM 0 points [-]

I've been asked for previous salaries in webform applications where the question is marked as required and won't take dummy info (I tried both "no response" and 0 without success)

Comment author: sketerpot 11 February 2015 12:55:29AM 0 points [-]

Other useful dummy values are $1, $42, $1,000,000, $9999999999999.95, and "'; DROP TABLE salary; --". As someone who has written input validation code for web forms on a few occasions, I personally give you my blessing to subvert them.

Comment author: sketerpot 28 January 2015 04:30:35AM *  4 points [-]

I'm not entirely sure what your argument is yet, but here's a simple example utility function that might be interesting as a baseline:

def utility(universe):
    return 42

This function halts for all inputs, and assigns each input a desirability value that can be compared with others. What sort of utility function are you imagining?

Comment author: Larks 04 October 2014 02:31:08AM 2 points [-]

How is this a rationality quote? I can see people thinking this is a good argument, especially if you politically agreed with the author, but it doesn't seem to be about rationality, or demonstrating an unusually great deal of rationality

Comment author: sketerpot 04 October 2014 02:48:19AM 8 points [-]

It would definitely be a rationality quote if it went on to quote the part where Eric Flint decided to test his hypothesis by putting some of his books online, for free, and watching his sales numbers.

Comment author: ialdabaoth 03 July 2014 08:52:06PM *  46 points [-]

It has to - otherwise you wouldn't be able to see what YOU upvoted/downvoted.

Also, otherwise you would be able to upvote or downvote something multiple times.

So clearly, it has to track somewhere.

If you guys need a SQL guy to help do some development work to make meta-moderation easier, let me know; I'll happily volunteer a few hours a week.

EDIT: AAAUUUGH REDDIT'S DB USES KEY-VALUE PAIRS AIIEEEE IT ONLY HAS TWO TABLES OH GOD WHY WHY SAVE ME YOG-SOTHOTH I HAVE GAZED INTO THE ABYSS AAAAAAAIIIIGH okay. I'll still do it. whimper

Comment author: sketerpot 04 July 2014 07:49:36PM *  7 points [-]

The Reddit guys really, really dislike doing schema updates at their scale. They were getting very slow, and their replication setup was not happy about being told to, say, index a new column while people are doing lots of reads and writes at the same time. So they eventually said "to hell with it; we'll just make a document database, with no schema, and handle consistency problems by not handling them. Man, do not even ask us about joins." This seems to have made them much happier than the 'better' database design they used to use, which is important when you're a too-small team dealing with terrifying scaling issues, and you know that a lot of people are watching you because they are the ones causing the scaling issues.

This design sure does make writing SQL queries a pain, though, and it's less than ideal for a site like Less Wrong, which doesn't do much changing the code.

View more: Next