• Olivier5
    6.2k
    It's not about sentences. It's about propositions. And propositions are proposed.
  • Olivier5
    6.2k
    it doesn't look like we can know a falsehood.TheMadFool

    Indeed, it doesn't look like you can.
  • TheMadFool
    13.8k
    Indeed, it doesn't look like you can.Olivier5

    Ad hominem?! I'll ignore that for the time being. Let's focus on the issue at hand. You claim that we can know falsehoods. Expand and elaborate (if you can :wink: ).
  • Olivier5
    6.2k
    I am not in the habit of talking to people who don't pay attention, sorry.
  • TheMadFool
    13.8k
    I am not in the habit of talking to people who don't pay attention, sorry.Olivier5

    I did pay attention and you're evading the question. Why? I wonder if it's because you can't prove your case.
  • Olivier5
    6.2k
    Did you manage to understand that Fitch can be extended to false propositions, or not yet?
  • TheMadFool
    13.8k
    Did you manage to understand that Fitch can be extended to false propositions, or not yet?Olivier5

    It's not about me, it's about you. Also, why are we discussing this like little children? You made a claim: Fitch's argument can be extended to false proposition. A philosopher would justify that claim. I'm waiting...
  • Olivier5
    6.2k
    You are a child, whether you are aware of it or not. You lack maturity. And you keep bitching petulantly about others. Stop bitching and start listening.
  • TheMadFool
    13.8k
    You are a child, whether you are aware of it or not. You lack maturity. And you keep bitching petulantly about others. Stop bitching and start listening.Olivier5

    Indeed, it doesn't look like you can.Olivier5

    Bitchin'? Me? :lol:
  • TheMadFool
    13.8k
    You are a child, whether you are aware of it or not. You lack maturity. And you keep bitching petulantly about others. Stop bitching and start listening.Olivier5

    By the way, I'm waiting for you to make an argument.
  • TheMadFool
    13.8k
    "We don't know that the earth is round"

    and

    "We believe that the earth is flat"?

    The differences are so easy to point out that I don't see the sense in asking about it.
    TonesInDeepFreeze

    You remark is such an obvious way to make a mistake that I don't see the sense in pointing it out.
  • TheMadFool
    13.8k

    ¬p can be stated as "p is false".

    q = ¬p

    q→Kq

    therefore

    ¬p→K¬p = all false propositions are known propositions.

    This is elementary, really. Reason for which I did not write it down, not wanting to insult people's intelligence. InPitzotl got it immediately. So make an effort, calm your contrarian demons and for once, TRY and understand these ultra basic logical steps above.
    Olivier5

    . Sorry.
  • Olivier5
    6.2k
    What are you sorry about, honey-bunny?
  • TheMadFool
    13.8k
    What are you sorry about, honey-bunny?Olivier5

    I'm sorry about your unsound argument. Again, let's stay focused on the problem at hand, shall we?

    I'll try and help you if that's even possible since you seem so confident about your position.

    Your claim: All false propositions are known propositions.

    All false propositions. I need one example of a false proposition:

    1. The earth is flat

    This proposition, you claim, is known. Ok, let's put it down in words: I know the earth is flat. Does that make sense to you? It doesn't to me. If it does to you, how? please and thanks in advance.
  • Olivier5
    6.2k
    This proposition, you claim, is known. Ok, let's put it down in words: I know the earth is flat.TheMadFool

    You know the proposition "the earth is flat". Otherwise you couldn't talk about it...
  • TheMadFool
    13.8k
    You know the proposition "the earth is flat". Otherwise you couldn't talk about it...Olivier5

    Knowing that there is a false proposition is not the same as knowing a false proposition.
  • Olivier5
    6.2k
    Indeed, and I am talking about knowing that there is a false proposition. What are you talking about?
  • TheMadFool
    13.8k
    Indeed, and I am talking about knowing that there is a false proposition. What are you talking about?Olivier5

    This :point:
    ¬p→K¬p = all false propositions are known propositions.Olivier5
  • Olivier5
    6.2k
    How do you read "Kp"?
  • TheMadFool
    13.8k
    How do you read "Kp"?Olivier5

    Kp= Know that p.

    So,

    1. if p = the earth is round, Kp = know that (the earth is round) [No problem]

    2. If p = the earth is flat Kp = know that (the earth is flat) [Problem]
  • Olivier5
    6.2k
    Okay so you interpret Kp as "It is believed that p is true" or "It is known that p is true". For me it only means: "p is known", i.e. some people know about proposition p.
  • InPitzotl
    880
    Why is
    q -> Kq
    being stated?
    TonesInDeepFreeze
    Because p -> Kp was stated.
    No one believes that as a generalization for all q.TonesInDeepFreeze
    Apparently some people do. It's an antirealist position; the p doesn't exist until it's proposed, and it isn't true until you say it is, or some such thing.
  • Olivier5
    6.2k
    Apparently some people do. It's an antirealist position; the p doesn't exist until it's proposed,InPitzotl

    On the contrary, it would be unrealistic to assume that there can exist English sentences that nobody speaking any English has ever composed or crafted... A realist view of the world does not imply that ideas nobody ever thought of exist already in some Platonic realm, waiting to be discovered.
  • InPitzotl
    880
    On the contrary, it would be unrealisticOlivier5
    Antirealistic != unrealistic
  • InPitzotl
    880
    ↪InPitzotl
    ?
    Olivier5
    You're confusing "antirealist"/"realist" with "unrealistic"/"realistic"... the terms convey completely different things. A realist (in this particular sense) is someone who accepts the reality of something, usually external. An antirealist denies the reality of something. The "something" in this case is English sentences nobody has mentioned. You're objecting to an accurate term describing what you're doing, on the basis of the ill-conceived notion that it was commentary.
  • TheMadFool
    13.8k
    Okay so you interpret Kp as "It is believed that p is true" or "It is known that p is true". For me it only means: "p is known", i.e. some people know about proposition p.Olivier5

    What does "p is known" mean?

    1. p = The earth is round

    p is known = The earth is round is known (all ok)

    2. p = the earth is flat

    p is known = the earth is flat is known (? not ok)
  • Olivier5
    6.2k
    What does "p is known" mean?TheMadFool

    As explained: some people know about the existence of proposition p.
  • TheMadFool
    13.8k
    As explained: some people know about the existence of proposition p.Olivier5

    You're equivocating. I'm out. Thanks for the interesting conversation. I learnt a lot from the exchange. Good day.
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