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  • silent_water [she/her]
    ·
    2 years ago

    actually a wise man once said that in order to get to 1, you must first reach 1/2. but to reach that, you must reach 1/4. and so on and so forth. therefore, the trolley cannot possibly move.

    • TreadOnMe [none/use name]
      ·
      2 years ago

      Holy shit, I actually laughed out loud reading that. Best use of Zeno's arrow paradox I've seen in a long time.

  • Llituro [he/him, they/them]
    ·
    2 years ago

    Mathematically moral answer is of course to pull the lever, since crushing the people on the real line would murder more before the second person died on the top than the top line will kill in its entirety.

    • silent_water [she/her]
      ·
      edit-2
      2 years ago

      the mathematical answer is that the same number of people die on both tracks. notice how the first track constructs a way to enumerate a set of people. the same enumeration can then be applied to the second set, because you're doing the exact same thing. the property that makes the reals dense and uncountable is precisely that it is impossible to assign one discrete element of an enumerable set to each real. "each real number" as a phrase doesn't make sense mathematically - the real numbers are the continuum.

      it's a very similar reasoning error as the one that leads people to think that an infinite stack of $20 bills must be worth more than an infinite stack of $1 bills.

      this is the joke in the OP - it doesn't matter whether you pull the lever or not, a false choice - and I've now thoroughly ruined it.

        • silent_water [she/her]
          ·
          edit-2
          2 years ago

          I didn't say it was? I'm comparing the sizes of sets by noticing the enumeration of the first set and that same enumeration applies to the second set.

            • silent_water [she/her]
              ·
              2 years ago

              no, emphatically:

              1. an infinite set is countable if there is a one to one mapping between it and the natural numbers. this is easy with the first set as you can literally count off, 1, 2, 3, etc..
              2. the second set is countable in exactly the same way.

              this is extremely basic set theory. you're deeply misinformed.

                • silent_water [she/her]
                  ·
                  2 years ago

                  no shit. I'm saying you can't use an enumerable set to produce a mapping with the reals. the natural numbers are an infinite set yet are definitionally countable as they are the ordinals.

                  disengage, you're arguing nonsense with someone with a literal degree in mathematics.

                    • ella [any]MA
                      ·
                      2 years ago

                      Respect people's right to disengage

                    • silent_water [she/her]
                      ·
                      2 years ago

                      that's the conceit of the joke, the idea that you can use an enumerated list and map them to the reals. if you could do such a thing, you'd immediately fall prey to Cantor's diagonalization argument. the train tracks are a continuum. they can be mapped to the reals. a neverending list of people cannot.

                        • WoofWoof91 [comrade/them]
                          ·
                          2 years ago

                          The premise of the joke is incorrect because the joke thinks “infinity = infinity”.

                          i fucking hate maths

                    • ella [any]MA
                      ·
                      2 years ago

                      Respect people’s right to disengage

                • silent_water [she/her]
                  ·
                  2 years ago

                  I'm pretty sure it's just a VOOOOTE joke about how there's no difference between the two parties, except aimed at math nerds.

            • replaceable [he/him]
              ·
              edit-2
              2 years ago

              Do you pull the lever killing one person for every integer

              Or do you do nothing, allowing the trolley to kill one person for every real number

              The meme establishes the same mapping on both infinities so both infinities have the same cardinality meaning that actually the second infinity is not continuum but aleph null

      • Llituro [he/him, they/them]
        ·
        2 years ago

        idk i just don't think it's fun to point out that the problem is inherently poorly posed. you're of course right that you can't actually consistently assign individual people to the reals.

        i propose that we set up a third track that lets us mow down a transfinite number of innocents.

    • panopticon [comrade/them]
      ·
      edit-2
      2 years ago

      Yeah it's like infinite "dudes getting run over and dying" density on the bottom track

      :Utilitarianism:

      Edit: infinite density per unit of distance. Sorry math majors, I only learned enough to scrape by in my degree, don't kill me

  • THC
    ·
    edit-2
    1 year ago

    deleted by creator

    • TerminalEncounter [she/her]
      ·
      edit-2
      2 years ago

      If you put a person for every rational number it would look the same as the bottom track (the rational numbers are dense) and if you put a person for every irrational number it would also look the same (because the irrational numbers are dense) - but the irrational numbers are uncountable and so are a larger infinity than the rational numbers, which are merely countable infinite. The density of the rational can be derived from the Archimedean property if the rationals (there is no largest rational and you can invert any rational, the exercise is left for the reader), the density of the irrational follows from the density of the rationals (simply use any irrational divisor and that between any rational x<y we know there exists at least one n such that x<n<y). The uncountability of the irrational follows from the fact that the reals are uncountable and the countable union of countable sets are themselves countable, i.e. the union of the rationals and irrational is uncountable therefore at least one of the rationals and irrational are uncountable, we know the rationals are countable by Cantors enumeration therefore it must be that the irrational are uncountable.

      • HoChiMaxh [he/him]
        ·
        2 years ago

        It's not really right to say one is a larger infinity - infinity is not a quantity and they are both infinite sets. What can be said is they have different cardinality.

        • TerminalEncounter [she/her]
          ·
          2 years ago

          By "size" in mathematics we mean the measure of the number of elements in the set.

          Given 2 sets we can determine which set has a larger number of elements - the "size" or measure - by comparing each element from each set. Given sets A and B, we say Size(A)>Size(B) if and only if when comparing each set element by element we have left over elements from A that cannot be matched up with elements from B because all the elements of B have already been compared once and only once to elements in A. For example, for sets {1,6,7} and {2} we compare each element by element, take any from {1,6,7} and compare it to the one element in {2}, there are still elements in {1,6,7} that are uncompared. Therefore, {1,6,7}>{2}.

          Cardinality literally just means the number of elements in the set, so the cardinality of {1,6,7} is 3. Notice, this is identical to the above definition I gave for "size".

          Therefore, it is proper to say that even though the cardinality of the reals and integers are "infinite" the reals are strictly larger than the integers or have a bigger "size" by the above definition. This follows from Cantors diagonal argument. To distinguish these two different infinities we can call one uncountable and one countable - or assign it an Aleph number. Either way, one is strictly more than the other despite both being infinite.

  • DoghouseCharlie [he/him, comrade/them]
    ·
    2 years ago

    I saw a video once about how some infinities are bigger than others, and the guy sounded so excited like it was some cool revelation about the natural world, but I think that's just some bs mathematicians came up with 'cause the were bored. It's not even original, children in elementary school were coming up with ways to out infinity each other.

    • StellarTabi [none/use name]
      ·
      2 years ago

      think of it like 2 rivers, both will flow an infinite amount of water, but if one river is bigger then holy shit it's bigger.

  • threshold [he/him]
    ·
    2 years ago

    I mean clearly one option is better than the other, but the 'better' option is also preventing a third lane from being built or transferred to- to the point where they'll threaten to go back on the worse lane if you dare suggest any alternative.

  • TeaFilledWall [none/use name]
    ·
    2 years ago

    Infinity is more a direction than a number. That's why math majors generally prefer to say approaches infinity rather than infinity.

    On a human scale infinity doesn't really matter. Bottom choice approaches infinity infinitely faster than top and would be a better choice. Would you rather 1 person die from disease a day or 10,000 people? It all approaches infinity in the end but one choice is demonstrably better.