• TheMadFool
    13.8k
    @Srap Tasmaner@andrewk@Nagase or anyone else

    1. All living things suffer
    2. No living thing wants to suffer
    3. No living thing that doesn't want to suffer wants to live
    Therefore,
    4. No living thing wants to live

    Lx = x is a living thing, Sx = x has to suffer, Wx = x wants to live

    Translating premises and conclusion in sequence:

    1. (x)(Lx > Sx)
    2. (x)(Lx > ~Wx)
    3. (x)(~Wx > ~Lx)................/~(Ex)(Lx)
    4. (Ex)(Lx).............................assume for reductio
    5. Ly > ~Wy...........................2 UI
    6. ~Wy > ~Ly.........................3 UI
    7. Ly > ~Ly.............................5, 6 HS
    8. La.......................................4 EG
    9. (x)(Lx > ~Lx).....................7 UG
    10. La > ~La..........................9 UI
    11. ~La..................................8, 10 MP
    12. La & ~La..........................8, 11 Conj
    13. ~(Ex)(Lx).........................4 to 12 reductio

    Is my proof good?

    Why is premise 1 redundant? It seems necessary in the English language argument?
  • Meta
    185
    The proof is correct. Your premises however are not equivalent with the English axioms because you need one more predicate to express "x wants to suffer".
  • noAxioms
    1.3k
    Sort of its own disproof then. The logic is sound, and the conclusion obviously contradicts reality, thus at least one of the premises must be wrong. I happen to take issue with all three of them.
  • TheMadFool
    13.8k
    (Y) Thanks

    Purely a logic exercise. Nothing more. :)
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