The Liar's paradox

Discussion in 'General Philosophy' started by Speakpigeon, Feb 6, 2019.

  1. James R Just this guy, you know? Staff Member

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    I thought that was the commutative property.
     
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  3. Baldeee Valued Senior Member

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    It is.
    I blame spellcheck on my ****ing Asus Memo Pad.
    Once the "error" is accepted the first time, it seems to correct every other occurrence it comes across.
    And I was in too much of a hurry to check.
    Me bad.

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  5. Baldeee Valued Senior Member

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    The force of gravity between two objects at a given distance apart (r) is given as F = G M1 M2 / r^2 where G is the gravitational constant, and M1 and M2 are the respective masses of the objects.
    This formula helps calculate the acceleration due to gravity at the earth's surface on an object:
    F = Ma, so the gravitational force on an object with mass M1 at the earth's surface will be given by G M1 M2 / r^2 where M2 is the mas of the earth, and r is the radius.
    This gives roughly 9.81 m/s^2 - at the surface.
    However, differentiate that force with respect to the radius and you end up with dF/dr = -2 G M1 M2 / r^3
    This is the rate of change of the force as you get higher (as r increases).
    If your intention is simply to match this gravitational force with thrust so that the net acceleration is zero and the object thus climbs with the same velocity, these equations will help you achieve that.
    What do either of these two have to do with the price of eggs?
    Yes it can.
    Think about it: if the attractive force reduces with distance then, assuming you have an upward velocity at the start, by applying the same force up you will gradually start to accelerate away, as the net force upwards increases.
    If you apply zero force upward then you will decelerate and fall back to the source.
    There is thus, even using this simplistic conceptualisation, a point between zero thrust and maintaining the initial thrust level at which the thrust can reduce in line with the decreasing attractive force such that the velocity can remain constant.
    It's not discrete blocks but a continuum.
    Otherwise you'll keep arguing Zeno's paradox and insist that the sum of an infinite sequence can't be reached.
    No, it really isn't.
     
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  7. Quantum Quack Life's a tease... Valued Senior Member

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    Again thanks for taking the time to post.
    Unfortunately I disagree and would like to discuss it further at some time in another thread. The detail required is off topic.

    Regardless IMO the math required to prove a paradox would mean that the reciprocation of equivalence would have to be broken. Thus a paradox can never be proven in math.

    x+(-)x = 0 =/= x+(-)x
    is I believe a way to show a paradox by revealing the zero in the middle as being both relative and absolute.
     
  8. Speakpigeon Valued Senior Member

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    I speak English as it is spoken, and better than most here, I dare say.
    EB
     
  9. Speakpigeon Valued Senior Member

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    Are you sure?
    If so, how could you possibly be sure?
    ???
    Seems we really don't speak the same kind of language.
    "Should" doesn't necessarily signal a moral judgement.
    Here, there's obviously nothing "moral" about it.
    EB
     
  10. James R Just this guy, you know? Staff Member

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    No, I'm not sure. No more sure than any of the philosophers who have spent a couple of millennia debating the matter.

    I don't think you're going to settle the matter here and now.

    It's usually about moral obligation, at least when it comes to the actions of human beings.
    I concede that, when applied to abstract concepts, it probably expresses expectation or probability, as you say.

    You asked:
    If you meant "Do you expect it will be possible to prove there is in fact no paradox?" or "Do you think it is likely that a proof that tehre is in fact no paradox will be discovered?", then my answer in both cases is: no.

    I could be wrong, of course. That's what not being sure means.
     
  11. Speakpigeon Valued Senior Member

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    OK, so perhaps you could look up what Wiki says: https://en.wikipedia.org/wiki/Liar_paradox
    There are a number of interesting resolutions proposed. Tell me if there's any you could agree with.
    EB
     
  12. iceaura Valued Senior Member

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    All of them depend on converting directly, assuming an equivalence, between the "sentence" and a logical statement - which you explicitly excluded, in post 6.

    So none of them apply to the OP here.
     
  13. Speakpigeon Valued Senior Member

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    Prove there is "equivalence".
    I didn't do that. Quote me when you allege I said something.
    EB
     
  14. iceaura Valued Senior Member

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    It's assumed, not proven, in your link.
    You excluded it, so the link does not apply.
    Post 6 of this thread, as cited.
     
  15. Speakpigeon Valued Senior Member

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    Sorry, you'd need to learn to articulate your point and quote people.
    EB
     
  16. fess Registered Senior Member

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    'This sentence is false" is completely self-referential. There is no information in it to be true or false. It makes no sense
     
  17. TheFrogger Banned Valued Senior Member

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    If the sentence is false, then the WHOLE statement can be considered to be untrue, but in order for this to be considered, the statement must BE CONSIDERED TO BE TRUE!

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  18. RainbowSingularity Valued Senior Member

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    it is mathematics
    the nature of the paradox lies in the mind of the perceptual field of comprehension by predisposition.
    this is not a paradox
    a paradox is not a state of lack of understanding or miss interpretation.
    a paradox is a confluence of opposing reality as express terms of compliant scientific data define.
    this makes a paradox.
    thus science is the nature to define the paradox, not psychology.
    a paradox of thought is the nature to not comply with rules of thought.
    this makes the real paradox the paradox of implied meaning.
    a claytons paradox

    you now heave the reality of 3 things
    1 a paradox
    2 a lack of understanding or miss interpretation
    3 an opposing opinion
     
  19. TheFrogger Banned Valued Senior Member

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    This sentence is false: 1=0.
     
  20. Write4U Valued Senior Member

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    The paradox lies in the "whole sentence".

    Therefore to say (1 = 0) is a false sentence in its entirety and thus not (1 = 0), which presents an unsolvable paradox......

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    p.s. however at quantum this paradox may disappear due to "superposition" of all four possible paradoxical states to become true under different circumstances.....

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    Last edited: Apr 9, 2019
  21. TheFrogger Banned Valued Senior Member

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    I understand your conclusion Write4u. The, "false" is part of the statement.

    The array of statements would be:

    This statement is true...
    This statement is false...
    It is not this statement that is true...
    It is not this statement that is false...
     
  22. Speakpigeon Valued Senior Member

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    Good points.
    And that's the points of it.
    I makes sense to me and it apparently made sense to many of the mathematicians and philosophers who have discussed it since the first Paradox of the Liar 2,500 years ago.
    The sentence is grammatical. It is a very simple sentence. We understand what it means. It is talking about something real, i.e. itself.
    So, I take your point that there is a problem but certainly not that it makes no sense. That's a cop out. The easy answer when you are unable to articulate what the problem is.
    EB
     
  23. Speakpigeon Valued Senior Member

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    Problem solved?
    EB
     

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