# What are your favorite thought experiments? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [November 19, 2023, 10:57pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394 "2023-11-19T22:57:35Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [November 20, 2023, 7:43pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/21 "2023-11-20T19:43:10Z")
Oh man, there are so many. I love a good thought experiment. [Hilbert’s Hotel](https://en.wikipedia.org/wiki/Hilbert%27s_paradox_of_the_Grand_Hotel), showing how counterintuitive infinity can be. [The Ross-Littlewood paradox](https://en.wikipedia.org/wiki/Ross%E2%80%93Littlewood_paradox), in which you add nine balls to a vase an infinite number of times and end up with an empty vase. [The St. Petersburg paradox](https://en.wikipedia.org/wiki/St._Petersburg_paradox) in which seemingly simple and correct application of probability theory results in a wildly incorrect answer. [The Chinese Room](https://en.wikipedia.org/wiki/Chinese_room); although I strongly disagree with Searle’s analysis of it, it’s still an interesting argument and requires some thought to refute. ---
**Author:** ![TheGunIsMightierThanThePen](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thegunismightierthanthepen/32/2981_2.png) [@TheGunIsMightierThanThePen](https://boards.straightdope.com/u/TheGunIsMightierThanThePen)\ **Post date:** [November 20, 2023, 7:59pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/22 "2023-11-20T19:59:36Z")
> [@Machine\_Elf](#): > > **[Wolfram Alpha says that in standard base-10 notation, this is a number about 60 million digits long](https://www.wolframalpha.com/input?i=%28256%5E3%29%5E8294400)**. One year of 4K video footage at 30 frames per second is about a billion frames - a one followed by nine zeros - so the above gigantic number represents X years of footage, where X is a number that’s about 51 million digits long. Nitpick: a 60 million digit number divided by 1 billion is not 51 million digits, instead, it would be ≈ (60 million - 9) digits ≈ 59,999,991 digits long. > [@Machine\_Elf](#): > > Years ago on a comedy website I saw an article that talked about the old idea that a monkey at a typewriter, pounding randomly on the keys, would eventually manage to type out Hamlet. That would be true if the monkey’s keypresses were statistically random, in that each key would have the same probability of being pressed as any other key, but my personal hunch is that a monkey banging away on a keyboard is _ **not** _ statistically random and thus they would never achieve this goal. Heck, I’d bet that if a human pounded “randomly” on a keyboard, and the resulting characters were converted into their ASCII binary equivalents and then run through the [Diehard statistical test suite](https://en.wikipedia.org/wiki/Diehard_tests), they’d fail those tests miserably. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [November 20, 2023, 8:25pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/23 "2023-11-20T20:25:38Z")
> [@TheGunIsMightierThanThePen](#): > > Nitpick: a 60 million digit number divided by 1 billion is not 51 million digits, instead, it would be ≈ (60 million - 9) digits ≈ 59,999,991 digits long. Good catch, thanks. My math had erroneously slashed my gigantic number by about 1/6, but your correction shows how big the number really is; dividing by a billion is barely noticeable. ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [November 20, 2023, 8:32pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/24 "2023-11-20T20:32:18Z")
I recently learned about Roko’s Basilisk, probably from this board. It’s like a cross between Pascal’s Wager, _The Ring_, and _The Matrix_. Good stuff. > **[Roko's basilisk](https://en.wikipedia.org/wiki/Roko%27s_basilisk)** > > Roko's basilisk is a thought experiment which states that an otherwise benevolent artificial superintelligence (AI) in the future would be incentivized to create a virtual reality simulation to torture anyone who knew of its potential existence but did not directly contribute to its advancement or development, in order to incentivize said advancement. It originated in a 2010 post at discussion board LessWrong, a technical forum focused on analytical rational enquiry. The thought ex While the th... ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [November 20, 2023, 8:51pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/25 "2023-11-20T20:51:45Z")
> [@TheGunIsMightierThanThePen](#): > > That would be true if the monkey’s keypresses were statistically random, in that each key would have the same probability of being pressed as any other key, but my personal hunch is that a monkey banging away on a keyboard is _ **not** _ statistically random and thus they would never achieve this goal. As long as there is some nonzero probability of hitting every key, the monkey would eventually produce Hamlet. It might just take longer than if the probability of each key were the same. In fact, there must be some nonuniform probability distribution that would produce Hamlet _faster_ than if the keys were uniformly likely. ---
**Author:** ![Q.Q.Switcheroo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/q.q.switcheroo/32/5713_2.png) [@Q.Q.Switcheroo](https://boards.straightdope.com/u/Q.Q.Switcheroo)\ **Post date:** [November 20, 2023, 8:54pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/26 "2023-11-20T20:54:45Z")
> [@Left\_Hand\_of\_Dorkness](#): > > I recently learned about Roko’s Basilisk, probably from this board. It’s like a cross between Pascal’s Wager, _The Ring_, and _The Matrix_. With a dash of [I Have No Mouth, And I Must Scream](https://en.m.wikipedia.org/wiki/I_Have_No_Mouth,_and_I_Must_Scream). ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [November 20, 2023, 8:55pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/27 "2023-11-20T20:55:08Z")
I can’t believe I left that out of the description. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [November 20, 2023, 8:57pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/28 "2023-11-20T20:57:39Z")
> [@Left\_Hand\_of\_Dorkness](#): > > I recently learned about Roko’s Basilisk, probably from this board. It’s like a cross between Pascal’s Wager, _The Ring_, and _The Matrix_. Good stuff. The scariest thing about Roko’s Basilisk is that allegedly Elon Musk and Grimes met while discussing it. ---
**Author:** ![griffin1977](https://avatars.discourse-cdn.com/v4/letter/g/977dab/32.png) [@griffin1977](https://boards.straightdope.com/u/griffin1977)\ **Post date:** [November 20, 2023, 11:24pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/29 "2023-11-20T23:24:04Z")
I’d also (and maybe more controversially) add I’m a fan of [the Trolley Problem](https://en.wikipedia.org/wiki/Trolley_problem) thought experiment, despite now being [meme-fied](https://knowyourmeme.com/memes/the-trolley-problem) to the point of being somewhat meaningless. I do think its actually a good thought experiment that highlights real complications in ethical systems. ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [November 20, 2023, 11:47pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/30 "2023-11-20T23:47:36Z")
I like Galileo’s thought experiment where he proved that heavy objects do not fall faster than light objects. Usually people think he dropped two stones from the tower of Pisa, a heavy one and a light one, and both dropped simultaneously. He probably never did that, and if he did, he did knowing the result. And he knew from thinking about it like this: Start postulating that heavy objects fall faster than light ones. Take two objects, one heavy, one light, and bind them together with a slack rope. A rope transmits force by pulling but not by pushing. Let them fall. The heavy object falls faster, the light one lags behind. Until the rope is tight, when the total mass of both bodies falling increases, so they suddenly accelerate. Which is absurd, so heavy objects do not fall faster than light ones. QED. I find this brilliantly visualized. ---
**Author:** ![TheGunIsMightierThanThePen](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thegunismightierthanthepen/32/2981_2.png) [@TheGunIsMightierThanThePen](https://boards.straightdope.com/u/TheGunIsMightierThanThePen)\ **Post date:** [November 20, 2023, 11:56pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/31 "2023-11-20T23:56:22Z")
Yeah, after considering it some more, you’re absolutely right. I must’ve been thinking along the lines of the monkey pressing multiple keys simultaneously with their palms, of which the probability distribution of consecutive keys would correspond to the monkey’s hand shape mapped onto the keyboard, implying certain keys would never follow each other because the other keys covered by that hand shape would interpose first. On the other hand, if the monkey was pressing keys one at a time, then like you said as long as each key has a nonzero chance of being pressed, then Hamlet is inevitable. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [November 21, 2023, 12:34am UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/32 "2023-11-21T00:34:50Z")
A quantum physics thought experiment that I only half understand but it still seems fascinating: what happens when an observer is themselves in a superposition of states according to another observer? [Wigner's friend - Wikipedia](https://en.wikipedia.org/wiki/Wigner%27s_friend) ---
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [November 21, 2023, 3:46am UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/33 "2023-11-21T03:46:18Z")
> [@Machine\_Elf](#): > > Years ago on a comedy website I saw an article that talked about the old idea that a monkey at a typewriter, pounding randomly on the keys, would eventually manage to type out Hamlet. Here is Bob Newhart’s take on that question. [https://www.youtube.com/watch?v=Ngmf8G5xKas](https://www.youtube.com/watch?v=Ngmf8G5xKas) ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [November 21, 2023, 6:38pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/34 "2023-11-21T18:38:46Z")
> [@markn\_1](#): > > [The Chinese Room](https://en.wikipedia.org/wiki/Chinese_room); although I strongly disagree with Searle’s analysis of it, it’s still an interesting argument and requires some thought to refute. That was going to be my one. I’m a fairly strong Dennettist on the Chinese Room. Also, the [Mary the Colour Scientist](https://en.wikipedia.org/wiki/Knowledge_argument) one. ---
**Author:** ![Q.Q.Switcheroo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/q.q.switcheroo/32/5713_2.png) [@Q.Q.Switcheroo](https://boards.straightdope.com/u/Q.Q.Switcheroo)\ **Post date:** [November 21, 2023, 6:47pm UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/35 "2023-11-21T18:47:49Z")
I’m a fan of the [Gettier Problem](https://en.m.wikipedia.org/wiki/Gettier_problem), in part because its creator threw a wrench into thousands of years’ worth of epistemology with a [single three-page article](https://fitelson.org/proseminar/gettier.pdf). ---
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [November 22, 2023, 12:02am UTC](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394/36 "2023-11-22T00:02:50Z")
My favorite thought experiment: which would taste better, the cheesecake or the apple pie? [Previous page](https://boards.straightdope.com/t/what-are-your-favorite-thought-experiments/993394.md?page=1)