Validity of a simple logical argument

Discussion in 'General Philosophy' started by Speakpigeon, Jan 23, 2019.

?

Is the argument valid?

This poll will close on Feb 22, 2019 at 2:00 PM.
  1. No

    54.5%
  2. Yes

    45.5%
  3. I don't know

    0 vote(s)
    0.0%
  4. The argument doesn't make sense

    0 vote(s)
    0.0%
  1. Write4U Valued Senior Member

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    Here is the mainstream connection between the two.
    What is the difference between logic and mathematics? - Quora

    https://www.quora.com/What-is-the-difference-between-logic-and-mathematics
     
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  3. Quantum Quack Life's a tease... Valued Senior Member

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    Logic are one of the building blocks of mathematics whereas mathematics is the building itself. Logic helps us in giving argument required for mathematical proofs. Logic is independent while mathematics depends on it.

    Which is why university department of science used to be called (maybe still are in some cases) the department of Philosophy. ( if I am not mistaken)
     
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  5. Speakpigeon Registered Senior Member

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    Could you explain what is logically inconsistent or not rigorous for example about Aristotle's syllogistic?
    EB
     
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  7. Speakpigeon Registered Senior Member

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  8. Write4U Valued Senior Member

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    I already replied to that question earlier. Not interested in repeating it all.......

    Please Register or Log in to view the hidden image!

     
  9. Quantum Quack Life's a tease... Valued Senior Member

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    ...that "nobody" includes yourself, of course.....
     
  10. Speakpigeon Registered Senior Member

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    761
    Me, I know there isn't one.
    Isn't that good enough?
    I think yes.
    EB
     
  11. billvon Valued Senior Member

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    That's a holdover from the days of Newton, where science was referred to as "natural philosophy."
     
  12. James R Just this guy, you know? Staff Member

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    32,043
    That's a "no" from you, then, I take it.
     
  13. arfa brane call me arf Valued Senior Member

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    6,092
    Ye gods.

    I posted something way back about a valid argument, how it's valid if it has premises and a conclusion.
    I say something like "if it has a valid conclusion", which is, on the face of it, not quite how it goes.

    Valid arguments have conclusions which are true or false, not "perhaps true or false" but actually only true or only false.
    So valid arguments present a conclusion which is true if the premises are satisfied, otherwise false.

    A conclusion can't be "maybe true, or maybe false", and Speakpigeon admitted a while ago in responding to my mistake, that a conclusion is true if, something or other, although he didn't say the conclusion is false if, some other thing.

    But that's all there is: true or false, there aren't any alternatives in a valid argument.

    Moreover, if A, B, and C are either true or false statements, and if they can only be true or false, not indeterminate or something else unspecified, then IF A THEN B is a statement about the truth values of A and B; IF A THEN B OR C is also true when IF A THEN B is.

    That looks a bit surprising, but all the THEN clause says is that B and C are independent of A, except that when A is true IF A THEN B can't be false. Logic, huh?

    So "valid conclusion" should be "a conclusion which can be satisfied", meaning it is either true or false, not both or neither. The computer you're using has transistors in it, for transistors it's true that when they're switched on we can abstract their state to the logical value "true"; if we didn't there wouldn't be any electronic computers. Computers therefore represent valid arguments (theories, engineering, etc), about physics.
     
  14. Speakpigeon Registered Senior Member

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    761
    Not quite. I remain open to the possibility that there is one.
    I looked for one, never could find one.
    Plus, different mathematicians and logicians have openly admitted their solution isn't quite the thing.
    But, yeah, I'd be very, very surprised if anyone produced anything like a convincing justification.
    Still, you can try.
    EB
     
  15. Speakpigeon Registered Senior Member

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    761
    • Please do not flame other members.
    You little fuck, when you claim I said something, quote the relevant post.
    EB
     
  16. arfa brane call me arf Valued Senior Member

    Messages:
    6,092
    Things Speakpigeon has posted in this thread:
    So it certainly looks like Speakpigeon understands the difference between true and false. True doesn't mean valid because a valid argument can be false, although he does seem to have trouble with that. Invalid conclusions? I think I can point to one or two made by . . . Speakpigeon.

    He posts this little gem, for instance:
     
  17. Speakpigeon Registered Senior Member

    Messages:
    761
    Well, that should be interesting. So, go on, prove to me I'm wrong and that "IF A THEN B", as written, is valid.
    EB
     
  18. arfa brane call me arf Valued Senior Member

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    6,092
    I don't need to prove it to you.

    All it says is if A is true, then so is B. If A is true and B is false, then (if A then B) is false. (consistency)
    If (not A) then (B or not B), is also valid.

    So if (if A then B) then (if (not A) then (B or not B)), is valid.

    Another way to say it is: ((not A) or B) implies (B or not B). (equivalence)

    It says nothing about a real physical world, only that A and B can be true or false independently.
     
    Last edited: Feb 13, 2019

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