View Poll Results: Do you think all these arguments are valid, only some are, or none of them?

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  • All these arguments are valid

    1 16.67%
  • Only some of these arguments are valid

    1 16.67%
  • None of these argument is valid

    3 50.00%
  • I don't know

    1 16.67%
  • These arguments don't make sense.

    0 0%
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Thread: All; therefore some?

  1. Top | #31
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    Quote Originally Posted by Speakpigeon View Post
    Quote Originally Posted by Jokodo View Post
    It's clear to everyone that you are on a crusade against what you call "mathematical logic" (and which other people simply call logic).

    It's also clear to everyone except yourself that you have - yet again - failed to demonstrate that it is useless, despite your childish insistence to the contrary.
    Again, I didn't ask for mathematical logic. Logic exists since Aristotle, 2,500 years ago, and indeed well before that in the minds of all human beings.

    Anyway, again, thank you for your patience, I'll try to reply to your posts later.
    EB
    Writing exists since the Sumerians, but you wouldn't expect me to answer a question "how do you write X" with a cuneiform character.

    Or would you?

  2. Top | #32
    Mazzie Daius fromderinside's Avatar
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    Quote Originally Posted by Speakpigeon View Post

    I'm interested in logic.
    EB
    Would you say that your view of of what is logic arises from rationalism and tradition?

  3. Top | #33
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    Quote Originally Posted by Speakpigeon View Post
    Quote Originally Posted by Jokodo View Post
    Either way it is irrelevant to the meaning of the logical operator ALL.
    In mathematical logic, sure.

    Whether it's relevant in real life, this was what I was trying to elucidate until you decided to start a lecture on mathematical logic.

    So, well done, but as I said, I'm not interested.

    I'm interested in logic.
    EB
    It is irrelevant in any properly defined system if logic.

    What exactly the English word "all" means in some, all or most contexts, to some, all or most speakers is an interesting question - but it's a linguistic question, not a logics question. I don't say this in a disparaging way - I have a linguistics degree. It's just not relevant to the question you yourself have staked out.
    Last edited by Jokodo; 10-28-2019 at 07:34 PM.

  4. Top | #34
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    All angels have wings;
    Therefore, some angel has wings.
    Few thoughts:

    1) There seems to be a silent (hidden) premise. If I unmasked it, the argument would look like this:

    P1. If all angels have wings, then some angels have wings
    P2. All angels have wings.
    Therefore C., Some angels have wings.

    2) quantifiers do not work the same in all situations. Sometimes, they are appropriately interpreted differently.

    There were 40 cookies, and I ate 40 cookies, so I ate all the cookies and no cookie went uneaten by me. I ate ‘at least’ some of the cookies, but did I eat some of the cookies? How is it exactly that some angels have wings if in fact all do? At least some, yes, but some?

    3) the argument I gave is valid, but it’s independent of any truth of the premises. Target the conclusion and glance around to see if there’s enough in what’s given to arrive at the conclusion.

  5. Top | #35
    Mazzie Daius fromderinside's Avatar
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    Quote Originally Posted by fromderinside View Post
    Quote Originally Posted by Speakpigeon View Post

    I'm interested in logic.
    EB
    Would you say that your view of of what is logic arises from rationalism and tradition?
    I asked because you wrote
    Again, I didn't ask for mathematical logic. Logic exists since Aristotle, 2,500 years ago, and indeed well before that in the minds of all human beings.

  6. Top | #36
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    Quote Originally Posted by fast View Post
    All angels have wings;
    Therefore, some angel has wings.
    Few thoughts:

    1) There seems to be a silent (hidden) premise. If I unmasked it, the argument would look like this:

    P1. If all angels have wings, then some angels have wings
    P2. All angels have wings.
    Therefore C., Some angels have wings.

    2) quantifiers do not work the same in all situations. Sometimes, they are appropriately interpreted differently.

    There were 40 cookies, and I ate 40 cookies, so I ate all the cookies and no cookie went uneaten by me. I ate ‘at least’ some of the cookies, but did I eat some of the cookies? How is it exactly that some angels have wings if in fact all do? At least some, yes, but some?

    3) the argument I gave is valid, but it’s independent of any truth of the premises. Target the conclusion and glance around to see if there’s enough in what’s given to arrive at the conclusion.
    That's quite clearly pragmatics. We don't expect speakers to make a weaker claim when they could have made a stronger one, so the weaker one seems infelicitous unless the stronger is false. I have a brother and two sisters. If I say "I have a brother" in answer to the question "do you have siblings?", people will judge me as an uncooperative interlocutor - despite having made a true statement. That it is indeed true can be verified by the fact that, were the question "do you have a brother", the expected answer would be "yes".

    The same happens with "some" - we assume the speakers knows whether "all angels" is also true, and we expect them to give us the most informative utterance that's compatible with their knowledge. The fact that they didn't say "all angels have wings" lets us conclude that it's incompatible with their beliefs - but nowhere did they tell us that some other angels don't have wings.

    It can be shown that the inference "and some don't/aren't" goes away in contexts where the speaker isn't expected to know, or when quantifying over situations, in some of which "all" doesn't hold while in others it does. For example "some of my great-great-grandfathers where farmers" seems perfectly acceptable when I only know what 4 of my 8 great-great-grandfathers did for a living, all 4 of which were farmers, and even suspect that the rest might have been farmers too. And the statement "if some of your family members are foreign citizens, you'll know what a pain in the ass the immigration office can be" obviously includes the case where all one's family members are foreign citizens.

    But thanks for demonstrating that building a logic on raw intuitions in a particular context is doomed to fail, and thus any logic worthy of the name has to make some (sometimes arbitrary) decisions about defining the semantics of its operators.

  7. Top | #37
    Contributor Speakpigeon's Avatar
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    Quote Originally Posted by fromderinside View Post
    Quote Originally Posted by Speakpigeon View Post

    I'm interested in logic.
    EB
    Would you say that your view of of what is logic arises from rationalism and tradition?
    Not one bit.

    My take is to apply the scientific method, which should have become obvious to all here given my many threads on the subject.

    For empirical evidence, I look at Aristotle, the Stoics and the Scholastic, as well as posters who are not biased by a schooling in mathematical logic, which is obviously wrong.

    I also take into account my own logical intuition as perception, in the same way that a scientist has to trust his perception.

    You've long been barking up the wrong tree with your "Rationalism". I abide not by Rationalism but by rationality, which I sensibly define as "facts plus logic", and I don't think anyone could fault me for that.
    EB

  8. Top | #38
    Contributor Speakpigeon's Avatar
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    Quote Originally Posted by fast View Post
    All angels have wings;
    Therefore, some angel has wings.
    Few thoughts:

    1) There seems to be a silent (hidden) premise. If I unmasked it, the argument would look like this:

    P1. If all angels have wings, then some angels have wings
    P2. All angels have wings.
    Therefore C., Some angels have wings.

    2) quantifiers do not work the same in all situations. Sometimes, they are appropriately interpreted differently.

    There were 40 cookies, and I ate 40 cookies, so I ate all the cookies and no cookie went uneaten by me. I ate ‘at least’ some of the cookies, but did I eat some of the cookies? How is it exactly that some angels have wings if in fact all do? At least some, yes, but some?

    3) the argument I gave is valid, but it’s independent of any truth of the premises. Target the conclusion and glance around to see if there’s enough in what’s given to arrive at the conclusion.
    As Jokodo said, pragmatics fully explains your observations. Logic is much more simple than that. Simple question, simple answer.
    EB

  9. Top | #39
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    Quote Originally Posted by fromderinside View Post

    I asked because you wrote
    Again, I didn't ask for mathematical logic. Logic exists since Aristotle, 2,500 years ago, and indeed well before that in the minds of all human beings.
    And?
    ______________

    So, which of my arguments are valid, and which are not?
    EB

  10. Top | #40
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    Quote Originally Posted by Speakpigeon View Post
    Quote Originally Posted by fromderinside View Post
    Quote Originally Posted by Speakpigeon View Post

    I'm interested in logic.
    EB
    Would you say that your view of of what is logic arises from rationalism and tradition?
    Not one bit.

    My take is to apply the scientific method, which should have become obvious to all here given my many threads on the subject.

    For empirical evidence, I look at Aristotle, the Stoics and the Scholastic,
    "Aristotle, the Stoics and the Scholastics" and "empirical evidence" in the same sentence.

    as well as posters who are not biased by a schooling in mathematical logic, which is obviously wrong.
    It's not "obviously" anything until you've provided an argument that it is. "I don't like it" is not an argument.

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