View Poll Results: Is the argument logically valid?

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  • No, the argument is not logically valid.

    3 37.50%
  • Yes, the argument is logically valid.

    5 62.50%
  • I don't know.

    0 0%
  • The question doesn't make sense.

    1 12.50%
  • The argument doesn't make sense.

    0 0%
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Thread: Everyone is female... Therefore ... ?

  1. Top | #1
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    Everyone is female... Therefore ... ?

    Here is an interesting logical argument:

    Everyone is female;
    Therefore, any siblings are sisters.
    Do you personally think this argument is logically valid?

    Thank you to cast a vote before posting any comment.

    Please note you can vote for several options.
    EB

  2. Top | #2
    Contributor ruby sparks's Avatar
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    I voted no.

    Sisters would only be children who have the same mother, so it does not follow?

    Oh bollocks, I screwed up your poll. I should have said yes. AArrhggh. Sorry!

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    Contributor DBT's Avatar
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    As the conclusion does follow from the given premise, the conclusion is logically valid in relation to the given premise. It appears that the premise is false.

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    Veteran Member Tigers!'s Avatar
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    As noted by DBT the argument is logically valid given the premise but the premise is the problem.
    NOTE: No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

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    Quote Originally Posted by DBT View Post
    As the conclusion does follow from the given premise, the conclusion is logically valid in relation to the given premise. It appears that the premise is false.
    Excellent, so you don't seem "confused" between validity and soundness, as some of our mathematically trained experts here have implied.

    ...
    Last edited by Tom Sawyer; 08-16-2019 at 05:45 PM. Reason: Calling out other users

  6. Top | #6
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    Quote Originally Posted by ruby sparks View Post
    I voted no.

    Sisters would only be children who have the same mother, so it does not follow?

    Oh bollocks, I screwed up your poll. I should have said yes. AArrhggh. Sorry!
    Again... And I'm not sure I understand your explanation.

    Still, you should be able to vote a second time, no?
    EB

  7. Top | #7
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    ...
    Last edited by Tom Sawyer; 08-16-2019 at 05:45 PM. Reason: Calling out other users

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    Sapere aude Politesse's Avatar
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    Quote Originally Posted by Speakpigeon View Post
    Here is an interesting logical argument:

    Everyone is female;
    Therefore, any siblings are sisters.
    Do you personally think this argument is logically valid?

    Thank you to cast a vote before posting any comment.

    Please note you can vote for several options.
    EB
    Well, we all start our lives as biological sisters to our siblings, anatomically speaking. But I assume you were after philosophical, not empirical, validation.

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    Mazzie Daius fromderinside's Avatar
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    Quote Originally Posted by Speakpigeon View Post

    Everyone is female;
    Therefore, any siblings are sisters.

    EB
    No.

    It fails logical limitation necessary to attribute everyone group. Is it everyone present is female, everyone everywhere are female? If it is everyone observed is female then then are the siblings product of the females present only? and are all the siblings of one parent or are the siblings are just those found in a group that was all female with other females who may have been mothers, grandmothers, daughters, or granddaughters.

  10. Top | #10
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    Quote Originally Posted by Speakpigeon View Post
    Quote Originally Posted by DBT View Post
    As the conclusion does follow from the given premise, the conclusion is logically valid in relation to the given premise. It appears that the premise is false.
    Excellent, so you don't seem "confused" between validity and soundness, as some of our mathematically trained experts here have implied.

    ...
    If educated people out of an entire field of study, collectively over time, appropriates a couple terms to denote a very specific technical meaning, the plain Jane common usage is likely divergent from its technical usage.

    The terms “valid” and “sound” are technical terms, and when used in accordance to their technical use, they don’t even apply for inductive arguments—a category error, it makes. So, while you may use the terms in the same way Larry, Moe, Curly, Shemp, and Joe use it when discussing inductive arguments, the technical usage has no place.

    But, you’re making a deductive argument, and while the five stooges can use the terms in common yet non-technical ways, just as they can with inductive arguments, the technical terms’ technical usage often trumps common usage when the discussion pertains to a technical field. No one really care how the almighty dictionary defines “kidnapping” while inside a courtroom. It’s technical usage is what then matters.

    A sound argument is a valid argument with true premises. That’s how it’s used by trained logicians. Coming in and using it like the everyday dictionary explains its usage intentionally creates ambiguity where there should be none.

    Validity doesn’t imply soundness whereas soundness implies validity — in accordance to technical usage.

    A sound argument is superior to an argument that is merely valid.

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