this post was submitted on 02 Oct 2025
433 points (98.4% liked)

Science Memes

17237 readers
995 users here now

Welcome to c/science_memes @ Mander.xyz!

A place for majestic STEMLORD peacocking, as well as memes about the realities of working in a lab.



Rules

  1. Don't throw mud. Behave like an intellectual and remember the human.
  2. Keep it rooted (on topic).
  3. No spam.
  4. Infographics welcome, get schooled.

This is a science community. We use the Dawkins definition of meme.



Research Committee

Other Mander Communities

Science and Research

Biology and Life Sciences

Physical Sciences

Humanities and Social Sciences

Practical and Applied Sciences

Memes

Miscellaneous

founded 2 years ago
MODERATORS
 
top 50 comments
sorted by: hot top controversial new old
[–] mumblerfish@lemmy.world 60 points 1 month ago* (last edited 1 month ago) (4 children)

In the top one you will never actually kill an infinite number of people, just approach it linearly. The bottom one will kill an infinite amount of people in finite time.

Edit: assuming constant speed of the train.

[–] ivanafterall@lemmy.world 37 points 1 month ago (2 children)

I'm going bottom.

NOT LIKE THAT. Not like sexually. I just mean I want to kill all the people on the bottom with my train.

[–] ConstantPain@lemmy.world 28 points 1 month ago

Too late! Now bend...

[–] a_person@piefed.social 6 points 4 weeks ago

So still sexually

[–] buffing_lecturer@leminal.space 6 points 1 month ago (5 children)

Limits still are not intuitive to me. Whats the distinction here?

[–] NoneOfUrBusiness@fedia.io 15 points 1 month ago

If people on the top rail are equally spaced at a distance d from each other, then you'd need to go a distance nd to kill the nth person. For any number n, nd is just a number, so it'll never be infinity. Meanwhile the number of real numbers between 0 and 1 is infinite (for example you have 0.1, 0.01, 0.001, etc), so running a distance d will kill an infinite number of people. Think of it like this: The people on the top are blocks, so walking a finite distance you only step on a finite number of blocks. Meanwhile the people on the bottom are infinitely thin sheets. To even have a thickness you need an infinite number of them.

[–] turdcollector69@lemmy.world 3 points 4 weeks ago

Different slopes.

On top you kill one person per whole number increment. 0 -> 1 kills one person

On bottom you kill infinity people per whole number increment. 0 -> 1 kills infinity people

You can basically think of it like the entirety of the top rail happens for each step of the bottom rail.

load more comments (3 replies)
load more comments (2 replies)
[–] magic_lobster_party@fedia.io 35 points 1 month ago (2 children)

Bottom.

Killing one person for every real number implies there’s a way to count all real numbers one by one. This is a contradiction, because real numbers are uncountable. By principle of explosion, I’m Superman, which means I can stop the train by my super powers. QED

[–] rooroo@feddit.org 15 points 1 month ago

Wait until your league of super heroes is up against the axis of choice.

load more comments (1 replies)
[–] pruwybn@discuss.tchncs.de 25 points 1 month ago (1 children)

Use the fact that a set people corresponding to the real numbers are laying in a single line to prove that the real numbers are countable, thus throwing the mathematics community into chaos, and using this as a distraction to sabotage the trolley and save everybody.

[–] NoneOfUrBusiness@fedia.io 6 points 1 month ago

Hey, maybe they're infinitely thin people, in which case you can (and necessarily must, continuum hypothesis moment) have one for every real number.

[–] aeternum@lemmy.blahaj.zone 19 points 4 weeks ago (1 children)

I think it was numberphile, or maybe vsauce, who did a video on infinities. It was really interesting. I learnt a lot, then forgot it all.

[–] filcuk@lemmy.zip 7 points 4 weeks ago

Ah yes, I remember my eyes glazing over as things got too complicated to fit through my thick skull

[–] ssfckdt@lemmy.blahaj.zone 19 points 4 weeks ago

The first one, because people will die at a slower rate.

The second one, because the density will cause the trolley to slow down sooner, versus the first one where it will be able to pick up speed again between each person. Also, more time to save people down the rail with my handy rope cutting knife.

[–] stupidcasey@lemmy.world 17 points 4 weeks ago (2 children)

I pull the lever, if the cart goes over the real numbers it will instantly kill an infinite amount of people and continue killing an infinite amount of people for every moment for the rest of existence.

If I pull the lever a finite amount of people will die instantly and slowly over time tending twords infinity but due to the linear nature of movement it would never actually reach Infinity even if there are an infinite number of people tied to the track a finite amount is all that could ever die.

[–] dharmacurious@slrpnk.net 7 points 4 weeks ago (3 children)

So you're going to let those infinite people on top stay tied to the track and starve to death slowly‽

load more comments (3 replies)
load more comments (1 replies)
[–] BilSabab@lemmy.world 12 points 4 weeks ago (3 children)

Is there a way to take both routes?

[–] ours@lemmy.world 11 points 4 weeks ago (2 children)

Hit the hand brake and drift that sucker.

[–] BilSabab@lemmy.world 4 points 4 weeks ago

with my knack for drifting i'll miss both and hit something else entirely even within this imaginary scenario

load more comments (2 replies)
[–] tiredofsametab@fedia.io 12 points 4 weeks ago

First, I start moving people to hotel rooms...

[–] BeatTakeshi@lemmy.world 7 points 4 weeks ago (3 children)

Top case is not the smallest infinite; going for prime number would save a lot of time for a lot of people before they die

[–] Schadrach@lemmy.sdf.org 15 points 4 weeks ago

The set of all primes is the same size infinity as the set of all positive integers because you could create a way to map one to the other aka you can count to the nth prime. Reals are different in that there are an infinite number of real between any two reals which means there's no possible way to map them.

[–] kadu@scribe.disroot.org 8 points 4 weeks ago

The set of primes and the set of integers have the same size, you can map a prime to every integer.

load more comments (1 replies)
[–] dontbelievethis@sh.itjust.works 7 points 1 month ago

Bottom. Greater probability that it gets stuck in the corpses.

[–] chunes@lemmy.world 7 points 4 weeks ago (1 children)

Good to know there are roughly 6 real numbers for every integer

If there are child real numbers then you can fit more.

[–] LadyAutumn@lemmy.blahaj.zone 6 points 1 month ago* (last edited 1 month ago)

In the top case has it been arbitrarily decided to include space in between the would-be victims? Or is the top a like number line comparison to the bottom? Because if thats the case it becomes relevant if there is one body for every real number unit of distance. (One body at 0.1 meter, and at 0.01 meter, at 0.001, etc)

If so then there's an infinite amount of victims on the first planck length of the bottom track. An infinite number of victims would contain every possible victim. Every single possible person on the first plank length. So on the next planck length would be every possible person again.

Which would mean that the bottom track is actually choosing a universe of perpetual endless suffering and death for every single possible person. The top track would eventually cause infinite suffering but it would take infinite time to get there. The bottom track starts at infinite suffering and extends infinitely in this manner. Every possible version of every possible person dying, forever.

[–] nuko147@lemmy.world 6 points 4 weeks ago (3 children)

I thought that the correct answer to these was making a loop on the right, merging the lines.

[–] Noodle07@lemmy.world 7 points 4 weeks ago

The answer is multi track drifting

load more comments (2 replies)
[–] Sunsofold@lemmings.world 6 points 4 weeks ago (2 children)

I ignore the question and go to the IT and maintenance teams to put a series of blocks, physical and communication-system-based, between the maths and philosophy departments. Attempts to breach containment will be met with deadly force.

load more comments (2 replies)
[–] trxxruraxvr@lemmy.world 6 points 1 month ago (3 children)

Doesn't matter, there are not enough people to try this anyway

[–] Thedogdrinkscoffee@lemmy.ca 6 points 1 month ago

Depends on the speed of the trolley.

[–] SpaceNoodle@lemmy.world 5 points 1 month ago

Not with that attitude

load more comments (1 replies)
[–] Tiger_Man_@szmer.info 5 points 4 weeks ago

Considering that there's a small but non zero chance of surviving getting ran over by a train some of them are gonna survive this and since there are infinite people that will result in infinite train-proof people spawning machine

[–] Matriks404@lemmy.world 5 points 1 month ago* (last edited 1 month ago) (3 children)

Imagine being the first one being killed on any of these tracks.

The probability of that is...?

Mathematicians tell me, please, because my mind is breaking.

[–] NoneOfUrBusiness@fedia.io 7 points 1 month ago

It's 0. I mean someone has to be the first, but betting on any particular person to be the first will necessarily be a losing bet.

load more comments (2 replies)
[–] CommissarVulpin@lemmy.world 4 points 1 month ago (6 children)

Okay, so what’s the point of “proving” that there some “infinities” are “bigger” than others? What’s the practical application here? Because an infinite hotel with an infinite number of guests is physically impossible, so I don’t see the point.

[–] carmo55@lemmy.zip 4 points 4 weeks ago

A practical application is for example in probability theory (or anywhere that deals with measures) such as this question:

If we generate a random real number from 0 to 1, what is the probability that it is rational?

Because we know that the continuum is so much larger in a sense than the set of rationals, we can answer this confidently and say the probability is zero, even though it is theoretically possible for us to get a rational number.

Statistics deals with similar scenarios quite frequently, and without it we wouldn't have the modern scientific method.

[–] NoneOfUrBusiness@fedia.io 3 points 1 month ago

Practical application in math tends to be like three degrees of separation and half a century removed from the math at play. In this case, all of modern mathematics is based on set theory, so it's more that this stuff allows us to do other, more practically useful math while knowing what we're talking about.

load more comments (4 replies)
[–] krooklochurm@lemmy.ca 4 points 4 weeks ago (1 children)

I masturbate until I forget about the decision I have to make and then put off cleaning my apartment until I finally just run out, randomly pull the lever, and never think of the consequences again.

Of course by that point everyone has already starved to death which is the worst possible outcome.

load more comments (1 replies)
[–] nathanjent@programming.dev 4 points 4 weeks ago (3 children)

An infinite amount of people on the track implies that the track is infinitely long. If that is not the case and the track is a normal length then the sudden addition of all that bio-mass in a finite space will cause a gravitational collapse. But will the collapse start on the first track or the second? Either way I hope you saved your game because you might lose your progress.

load more comments (3 replies)
[–] Harvey656@lemmy.world 3 points 4 weeks ago (3 children)

I mean, the bottom. The trolley simply would stop, get gunked up by all the guts and the sheer amount of bodies so close together. Checkmate tolley.

load more comments (3 replies)
[–] AkatsukiLevi@lemmy.world 3 points 1 month ago (2 children)

Hold the lever halfway so the trolley picks both rails at the same time, to ensure highest possible kill comboq

load more comments (2 replies)
[–] Honytawk@lemmy.zip 3 points 4 weeks ago

The top one, because time is still a factor.

Sure, infinite people will die either way, but that is only after infinite time.

load more comments
view more: next ›