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Comment author: lightpurpledye 24 April 2013 08:43:21AM 1 point [-]

Note: the hypothesis submitted by the people who proposed the experiment was correct: http://www.asc-csa.gc.ca/eng/media/news_releases/2013/0416.asp

Comment author: lightpurpledye 22 April 2013 11:44:26PM *  7 points [-]

(Written before watching)

Skill #1. I would have failed this if I had not had the opportunity explicitly pointed out to me.

Skill #2.

a. Water forms a cylindrical shell around the towel.

b. Water is pushed into the parts of the towel which are least compressed, but does not exit from the towel.

c. Water flies off from towel equally in all directions perpendicular to the towel axis.

d. Water adheres to towel, in a spiral pattern following the way the towel is wrung out.

e. (Something else I haven't thought of.)

Skill #3. I'm not really sure what you mean by "incorporate prior information", and how it differs from skill #2/4. To generate the possibilities in number 2, I used my model of how wrung towels behave on earth, and my knowledge of how things behave in space, mostly from Don Pettit videos (which I assume is also the source of the linked video). But I don't really have clear physical intuitions about the situation, nor do I have enough knowledge of physics to be able to work it out.

Skill #4. Of my options in number 2, I'd go for c. 20% d. 10% a. 10% b. 5%. ( therefore e. 100-45=55%) Note: I was loath to put down numbers, because I have basically no way to calibrate those guesses, but in the spirit of the exercise, those are as close to my true expectations as I can manage. On reflecting, I do actually expect greater than even odds that none of my answers are right, so even though it feels like cheating to say " 55% something I haven't thought of", I'm sticking with it.

(Video watching time) Skill #5. I can see in a very superficial way why it works the way it does. I don't think this equates to real understanding though.

Skill #6. So first of all, it wasn't Don Pettit. So I lose points there. :p Secondly, the answer is somewhere between my prediction a. and my non-prediction e. I don't think I can chalk that down as a win. Partial success: something I hadn't thought of happened (water moving onto the hands), which I had predicted at 55%. Partial failure: something I had thought of happened (water forming a cylindrical shell around the towel), but I had only predicted it was 10% likely. Neither of these are clear cut, you could swap the labels of "success" and "failure" and not be inaccurate…

Thanks for the puzzle!

ETA: line breaks, formatting

Comment author: razor11 05 July 2012 05:51:45PM *  0 points [-]

those who are effected by our actions

Minor nitpick: effected' should be 'affected'.

Comment author: lightpurpledye 07 July 2012 05:14:06PM -1 points [-]

To be fair, we do also owe it to those who are effected by our actions (e.g. our children).

Comment author: ChristianKl 27 May 2012 09:08:44PM 0 points [-]

Is listing to public radio really a better use of your time than listening to a podcast about an interesting topic?

Comment author: lightpurpledye 27 May 2012 11:25:31PM 1 point [-]

As a non-American, the way I listen to American public radio is via podcasts. And the programmes that I listen to are, in general, about topics I find interesting.

Comment author: ohwilleke 12 July 2011 09:52:20PM 2 points [-]

There are not an infinite number of possible hypotheses in a great many sensible situations. For example, suppose the question is "who murdered Fred?", because we have already learned that he was murdered. The already known answer: "A human alive at the time he died.", makes the set finite. If we can determine when and where he died, the number of suspects can typically be reduced to dozens or hundreds. Limiting to someone capable of carrying out the means of death may cut 90% of them.

To the extent that "bits" of evidence means things that we don't know yet, the number of bits can be much smaller than suggested. To the extent that "bits" of evidence includes everything we know so far, we all have trillions of bits already in our brains and the minimal number is meaningless.

Comment author: lightpurpledye 17 July 2011 11:51:01AM 0 points [-]

What about the aliens who landed on earth, murdered Fred and then went away again? Or the infinite number of other possibilities, each of which has a very small probability?

What confuses me about this is that, if we do accept that there are an infinite number of possibilities, most of the possibilities must have an infinitesimal probability in order for everything to sum to 1. And I don't really understand the concept of an infinitesimal probability -- after all, even my example above must have some finite probability attached?

Comment author: lightpurpledye 07 April 2011 10:11:12AM *  0 points [-]

This! I had already emailed Eliezer about this, so I was delighted when he mentioned it in the preamble for the current chapter (71).

An advantage that hasn't been mentioned thus far: audiobooks are very useful for people who are visually impaired.

Comment author: bigjeff5 04 March 2011 04:12:24AM 9 points [-]

When it was noticed in the 1800's that the perihelion of Mercury did not match what Newton's inverse-square law of gravity predicted, did we change the way math works? Or did we change our understanding of gravity?

Math is the most fundamental understanding of reality that we have. It is the most thoroughly supported and proven aspect of science that I know of. That doesn't mean that our understanding of math can't be fundamentally flawed, but it does mean that math is the last place we expect to find a problem when our observations don't match our expectations.

In other words, when assigning probabilities to whether math is wrong or Newton's Theory of Gravity is wrong, the probability we assign to math itself being wrong is something like 0.000001% (sorry, I don't know nearly enough math to make it less than that) and Newton's Gravity being wrong something like 99.999999%.

See what I'm saying?

Comment author: lightpurpledye 21 March 2011 03:58:34AM 12 points [-]

Woah, I think that's a little overconfident...

You're saying that in the mid nineteenth century (half a century before relativity), the anomalous precession of Mercury made it seem 99.999999% likely that Newtonian mechanics was wrong?

After all, there are other possibilities.

cf. "When it was noticed in the 1800's that the perihelion of Neptune did not match what Newton's inverse-square law of gravity predicted, did we change the way math works? Or did we change our understanding of gravity?" In this case we actually postulated the existence of Pluto.

Similar solutions were suggested for the Mercury case, e.g. an extremely dense, small object orbiting close to Mercury.

And that's leaving aside the fact that 99.999999% is an absurdly high level of confidence for pretty much any statement at all (see http://lesswrong.com/lw/mo/infinite_certainty/ ).

If I were a nineteenth century physicist faced with the deviations in the perihelion of Mercury, I'd give maybe a 0.1% probability to Newton being incorrect, a 0.001% probability to maths being incorrect, and the remaining ~99.9% would be shared between incorrect data /incomplete data/ other things I haven't thought of.

However, I agree that we can probably be more confident of results in maths than results in experimental science. (I was going to distinguish between mathematical/empirical results, but given that the OP was to do with the empirical confirmation of maths, I thought "mathematical/experimental" would be a safer distinction)

Comment author: MBlume 09 February 2011 06:43:16PM 1 point [-]

It occurs to me that 'l' is also 'move right' in vim. I think I find my rightmost three fingers hovering on the top row when I move about for this reason. Wonder if I should try to remap those movement keys...

Comment author: lightpurpledye 19 February 2011 01:45:22AM 2 points [-]

The vim movement keys actually work surprisingly well in Dvorak. Up/Down are next to each other on your left hand, right/left are on the appropriate sides of your right hand.