packbat: One-quarter view of the back of my head. (Default)
Poll #2386 The Chocolate Dilemma
Open to: Registered Users, detailed results viewable to: All, participants: 1

There is a sack of chocolate and you have two options: either take one piece from the sack to yourself, or take three pieces which will be given to Dylan. Dylan also has two options: one pieces for himself or three to you. After you both made your choices independently each goes home with the amount of chocolate he collected.

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Take one piece for yourself.
0 (0.0%)

Take three pieces for Dylan.
1 (100.0%)

From, via.
packbat: One-quarter view of the back of my head. (Earth:Harmless/WikiGuide)
So, just out of curiosity...

[Poll #1331652]

Feel free to elaborate in comments, natch.

EDIT: If I did it right, it should be posting to a "twitter" filter - tell me if you want on it.
packbat: One-quarter view of the back of my head. (Default)

It's hard to ignore the fact that today is Election Day in the U.S. If you went to the polls today, tell us what it was like. Long line? Free stickers? Hanging chads? We want the details.

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At Woodlin Elementary School in Maryland, lines were much like last election's - about an hour at 7 a.m. opening, according to reports from my siblings and mother, and forty minutes or so around nine a.m. when my dad ([ profile] zhurnaly) and I went. Campaigning was light - other than road signs, there was only a representative from the teachers' union (I think) with a slate of endorsements. ([ profile] zhurnaly asked her about the local slots initiative - creditably, the union had no stance and she didn't feel too good about it.) (Oh, and I took one of her sheets to help me decide on the school board race where I was still dithering.)

Attitudes were cheerful. The PTA had a bake sale running. The electronic voting machines read my touchscreen inputs correctly (and thank goodness they'll be gone next election!). It might start raining later, but it was fairly nice when we went.

Oh, and we got free stickers. [ profile] zhurnaly gave me his as a joke.
packbat: One-quarter view of the back of my head. (darwin has a posse)
Another classic game-theory hypothetical for you all:

Yesterday, you and an accomplice pulled off the bank job of the century - a haul large enough for each of you to retire to your favorite island paradise with no extradition to your home country. The money is all untraceably socked away in secret bank accounts, but, unfortunately, the police caught up to you on your way out of town. After a high-speed chase, you both ended up in separate cells in solitary, where you have been stewing away overnight.

This morning, the state attorney visited you in your cell.

"Okay, listen up," he said. "I know you'll just deny it if we ask, but we know you two did it, even if we can't prove it. So I'm going to offer you a deal. Even if both of you say nothing, we can get a year inside for both of you on a reckless endangerment charge for that wild driving last night. I'm willing to drop that charge and let you go if you'll testify against your partner.

"But before you start thinking about altruism and all that, I'm warning you - my partner's right down the hall, offering the exact same deal to your partner. If you clam up and your partner talks, you'll get twenty-five years and your partner will be let off scot free. If you both testify, I'll give you time off for cooperation - fifteen years apiece.

"That's the deal - your choice. Think it over. I'll be back tonight."

Assume that you do not know and have no loyalty to your accomplice - all you want is a minimum sentence for yourself. (You can make up a scenario to explain it if you like - the key part is that you're strangers, only together for one job.)

[Poll #1207554]

(Edit: Anyone interested in further reading may wish to read the Wikipedia Prisoner's Dilemma article.)

(Edit 2: The crosspost to [ profile] thequestionclub may be found here.)
packbat: One-quarter view of the back of my head. (Earth:Harmless/WikiGuide)
[Poll #1205229]


May. 30th, 2008 09:11 pm
packbat: One-quarter view of the back of my head. (darwin has a posse)
Reposted from my Facebook:

Imagine the following scenario (a variation on the classic dilemma known as Newcomb's Problem):

About six months ago, a crack team of psychologists came up with a brilliant new device, and decided to run a curious experiment to test it. The experiment takes the following form:

  1. Each subject, chosen by lottery, is provided with the money to purchase two identical plain manilla envelopes.
  2. They and their envelopes are given free transportation to the lab, where they (but not the envelopes) fill out a survey.
  3. They wait approximately one hour, and then are ushered into the experiment room.
  4. In that room, they are permitted to examine three stacks - one containing twenty U.S. fifty-dollar bills, one containing twenty fifty-dollar-bill-sized pieces of blank U.S. fifty-dollar-bill stock, and one containing one thousand U.S. one-thousand-dollar bills.
  5. An attendant removes the stack of thousand-dollar bills. They are instructed to privately place one of the remaining stacks in each of their manilla envelopes, so that they would have two apparently-identical envelopes, and then signal.
  6. On the signal, the attendant returns with a case, which either does or does not contain the million dollars. The subject then gives either of their two envelopes in return for the case.

There is only one catch in this procedure: the case either contains blank bills or the million, as follows. If the psychologists predict the subject would return the envelope with the thousand dollars, the case contains the million. But if the psychologists predict that the subject will return the envelope with the blank paper, the case contains blank paper. And in each of the one hundred trials so far, the psychologists have always gotten it right. Everyone has either left with the thousand or left with the million.

(Edit: Well, not quite. A few clever people thought to randomize the envelopes so that they didn't know whether they lost the thousand or not. About half of them walked away with a thousand, the other half with nothing.)

The experiment is valid - it has been tested by dozens of experts in experimental protocol, sleight of hand, hypnotism, and every other relevant field. They neither coerce your choice nor switch out the million if you choose to keep the thousand.

You are in the room, with your two envelopes, and the attendant is before you with his case.

Do you give him the thousand dollars or the blank paper?
packbat: One-quarter view of the back of my head. (Default)
Surprisingly topical for a Sunday, the following question, reposted from [ profile] thequestionclub:

Inspired by a thread on IIDB, a two-part question:

1. Do you believe that at least one god is real? (For purposes of this question, interpret the word "real" as per Eliezer Yudkowsky's The Simple Truth.)

2. a. (For those of you who answered "yes" to the above:) Describe this god (or a few of the most important gods, if you ascribe to a more-than-one-god theory) to the best of your ability. If you are unsure, say, "I'm not certain of this, but I believe [...] with X confidence". If you cannot find the words, say, "I don't know if I can express this properly, but it is something like [...]". If you are tempted to say nothing at all, please: say something, however incredibly hedged. I specifically promise not to judge anything you say in any comment I make on this post. Just say what you believe.

b. (For those of you who answered "no" to the above:) Describe the characteristics that something would have to have to be called a god. Does it need to be a person? (Would being a person help?) Does it need to be able to subvert the laws of physics? Does it need to be benevolent?


Unlike on the post on [ profile] thequestionclub (edit: which is here if you are curious), anonymous comments are allowed and unscreened, and I've temporarily disabled IP logging. Feel free to weigh in however you feel comfortable!
packbat: One-quarter view of the back of my head. (arecibo)
Naming no names, of course.

Edit: And greetings to all the peeps from [ profile] the_zaniak chiming in!

Edit #2: And [ profile] thequestionclub! (Wow, that's a lot of people.)

[Poll #1166935]
packbat: One-quarter view of the back of my head. (Default)
Because the question is too pressing to be left unasked.

[Poll #1157201]
packbat: One-quarter view of the back of my head. (wtfcu)
From [ profile] ceruleanst: science brings us the most-wanted and most-unwanted songs, based on the opinions of 500 respondents to a spring-1996 web survey. If their assumptions are correct...

[Poll #1124531]

Enjoy! (Or don't enjoy!)
packbat: One-quarter view of the back of my head. (Default)
[Poll #1115036]

(Judging by the blogosphere, "awful" ought to be winning out by a vast margin.)
packbat: One-quarter view of the back of my head. (Silhouette)
[Poll #1058418]

(No, "something"-made-it-happen ain't an option. I already said that no thing made it happen.)

Edit: Note that the scenario described involves causal indeterminism, not predictive indeterminism.

The context. )
packbat: One-quarter view of the back of my head. (Silhouette)
This fall at UMD, I'm taking advantage of my 10-credit tuition remission/fourth year of the four year scholarship free registration to take another non-engineering course dear to my heart: PHIL282: Action and Responsibility. I mean, just read the catalog entry!
If what science tells us is true, that every event has a cause, can we still have free will? Does a horrible childhood mitigate a violent criminal's blameworthiness? Is anyone ever truly responsible for anything? This course deals with these problems in ethics, philosophy of mind, and metaphysics, covering such topics as personal agency, free will, and responsibility. The current version of the course will focus on theories of free will and responsibility, and the related phenomena of reactive emotions (like gratitude and guilt) and excuses (e.g., accidents and mistakes).

The required text for the course will be: Robert Kane, A Contemporary Introduction to Free Will (Oxford), possibly along with further readings containing highlights of contemporary debates over issues of responsibility.

Written requirements will include midterm and final exams, plus regular short writing assignments.

(Incidentally, I've started reading the book - it seems pretty good, and about as easily readable as philosophy can get.)

Now, most of you aren't taking the class. But it occurs to me it'd be interesting anyway to see. (And, after all, my stance could easily change over the semester.)

(Oh, if you're not sure, go ahead and be ambitious and say what you think. If I omitted your stance, of course, that's different.)

[Poll #1043677]

Link List

Aug. 16th, 2007 08:10 am
packbat: Wearing a open-frame backpack, a pair of sunglasses, and a wide, triangular grin. (hiking)
[Poll #1040097]

P.S. Have started doing research back at school - will be busy most days. No, it's not about LJ; I'm a Mech. E.
packbat: One-quarter view of the back of my head. (efw O.P.)
From [ profile] alchemi's prompt:

[Poll #1034660]
packbat: One-quarter view of the back of my head. (Bumper)
Hey - done three posts already, may as well keep going!

[Poll #1031766]
packbat: One-quarter view of the back of my head. (Default)
If there are one or more people on your friends list who make your world a better place just because they exist, and who you would not have met (in real life or not) without the internet, then post this same sentence in your journal.

Oh, and as long as I'm copying other people, here's one based on the idea of some Pharyngula commenter from months ago – if you were going to wear a sign with the following on it for a day, how would you fill in the blanks?

[Poll #1002174]


Jun. 11th, 2007 01:05 pm
packbat: One-quarter view of the back of my head. (darwin has a posse)
[Poll #1001244]

My take. )
packbat: One-quarter view of the back of my head. (Green RZ)
1. Just restarted my paper diary. Handwriting (well, printing) still terrible.

2. My community college campus shop seems to offer the best prices on printmaking paper. I still don't believe it.

3. Laptop's back! Did I mention that? I don't think I mentioned that.

4. Meaningless poll!

[Poll #997142]

Rule of Law

May. 3rd, 2007 01:43 pm
packbat: One-quarter view of the back of my head. (darwin has a posse)
Pop quiz!

[Poll #978071]

Inspired by.
packbat: One-quarter view of the back of my head. (efw O.P.)
I was lying in bed the other night thinking about bases of arithmetic....

You know, it's kinda odd that insomnia due to math isn't that rare, for me.

Anyway, I was thinking about bases of arithmetic, and Hal Clement's throwaway gag in Still River* about an ancient academic controversy over octal versus duodecimal at the School in his story, and the problem of factoring, and how weak the theoretic justifications for all those specific bases are.

You may be surprised at this claim. "But octal is clearly the most rational," you might be saying. "Binary is the most fundamental base of arithmetic, and octal is a logical extension of that."

Uh-huh. Logical extension how, exactly? If you've got an old 24-bit mainframe?

"That just implies hexadecimal is even better."

Yeah, okay, but that's still just one advantage – convenient relation to binary. Besides, larger bases get more and more inconvenient as you have to memorize more and more figures and (more importantly) bigger and bigger multiplication tables. So hex is great for computer scientists, and octal used to be great for computer scientists, but that doesn't translate to their being the best day-to-day radices. They've got one advantage – one huge advantage – but it's only a useful advantage in a few contexts.

And when we turn to duodecimal, base 12 (and its cousin, sexagesimal, base 60), we find a similar sole advantage: the base has many factors. Yeah, that's great if you're writing fractions – 1/3 becomes 0.4duodecimal, 4/15 becomes [00].[16]sexagesimal (each bracket is a decimal representation of one figure), etc. – but how often do you need to?

Actually, that gets to the key point: what do you need to do regularly with a number system? Really, it comes down to:

  • Write.
  • Add.
  • Subtract.
  • Multiply.
  • Divide.

...pretty much in that order. I mention "write" because while messing with the basic principle of positional notation may be fun, standard positional notation is a pretty solid, intuitive way to write down how many books you have on the second shelf of your bookcase.** And while binary may be logically the simplest radix, 10101 takes up a lot more space than 21†. (Oh, and just coming up with symbols for a sexagesimal system is horrid, forgetting all its other disadvantages.)

So, what about these others? Well, we're only looking at standard positional systems, so whatever advantages balanced ternary systems have, we're ignoring them. Anyway, in standard positional systems, 'add' and 'subtract' pretty much make only one contribution to complexity: how many digits are in your basic addition tables. And since we humans have shown that we can handle base 10 pretty well, anything up to around that size is probably fine. Multiplication is almost the same, but there's an advantage for highly composite (and not-quite-highly composite) radices – all the rows with divisors of the base are simpler. (I guess that means duodecimal isn't quite as pointless as I thought.) Division – well, you're doing long division, so have to come up with a compromise between having fewer digits (higher radix) and fewer multiples of the denominator (lower radix). Oh, and having lots of divisors means fewer recurring 'decimals'.

This sounds like it's building up to sell duodecimal after all. No, it isn't.

I'm saying we should use senary. Base six.

The actual inspiration for this came that night, when I was comparing duodecimal and octal to decimal. Duodecimal, I had decided, had the advantage of many factors. Octal, of being a power of 2. But what about decimal?

Well, as it happens, I had already realized that decimal was unusually good at testing divisibility. As it happens, there are two types of numbers that are very easy to check divisibility of in a given base: factors of the base, and adjacent natural numbers to the base. In decimal, the first group consists of 2, 5, and 10. The latter group consists of 9 and 11. Divisibility by the first set can be checked through examining the final digit – an even digit means multiple of 2, 5 or 0 mean multiple of 5, 0 means multiple of 10. This is really easy – in big O notation, it's O(1), meaning it takes a constant length of time for any number. As for 9 and 11, it's easy to prove from modulo arithmetic that you need merely add all the digits (for 9 – 'casting out nines', basically) or alternately add and subtract (for 11) to check divisibility. These are both O(log n) – the time they take is proportional to the length of the number, written out.‡

Now, all bases get the benefits of these two effects. But because 9 is a power of 3, in base 10 this means that testing divisibility by 2, 3, 5, and 11 is easy. Four of the first five prime factors, accounting for 75.76% of all numbers. That's pretty good – only missing the seven. Duodecimal only gets 2 and 3 from its factors, and 11 and 13 from the casting-out methods, so it misses five and seven. Octal would get seven, of course (one less than the base), but it only has two as a prime factor and nine = three squared as one over the base, so it misses five.

But six doesn't. It misses eleven, but with seven it gets 77.14%, better than base 10, which beat bases 8 and 12. It's smaller than 10, which means only six symbols and 21 unique entries each on the addition and multiplication tables. (It would be 36, but since 2+3 = 3+2 and 2*3 = 3*2, a large fraction drop out.) Being smaller also makes long division easier – you need only write 5 multiples of the divisor, instead of 9. Against that, you've got longer numbers, but even when you get pretty large (e.g. the age of the universe, 13.7 billion years), it's not a big difference (13 senary figures as opposed to 11 decimal figures). Being divisible by 2 and 3 means 1/2, 1/3, and 1/4 are all easy (1/4 = 0.13senary), and adds extra simplicity to two rows of the multiplication table (which has only six to start with, including the ones row).

Add these factors together, and I think that makes 6 the perfect base.§

But hey, who cares what I think!

[Poll #924107]

* Which is actually a pretty lame book, on rereading, but I still like it.
** Not that bijective numerations are that hard to count in – I just didn't want every link to be to Wikipedia.
† I'm not counting the Adobe Photoshop manual in this count.
‡ Which, you must note, is often much less than the number itself.
§ Yes, I did in fact spent seven hours writing a long, technical discussion of the relative merits of five different systems of positional notation, combined with an a priori enumeration of the most important principles of a number system, just so I could conclude with that sentence. I regret nothing!


packbat: One-quarter view of the back of my head. (Default)

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