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Thread: What is the definition of necessary and sufficent evidence

  1. #1 What is the definition of necessary and sufficent evidence 
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    I am reading a book on pseudo science and in a passage I just read it says:

    In the example above, people are most influenced by the number (and salience) of couples who adopt and subsequently conceive. In so doing, people implicitly confuse necessary and sufficient evidence: They seem to be reasoning that if there are a fair number of such positive cases, then the phenomenon must exist, or the relationship must be valid.
    They have talked a bit about the two but not really explained it such that I understand the difference properly. I also did a google but didn't find a neat definition of either.

    Could someone who understands what they mean define the two for me in clear terms please.


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  3. #2  
    Universal Mind John Galt's Avatar
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    It would help if you had said which two terms you wanted defined.
    number and salience
    adoption and conception
    necessary and sufficient

    It is worth noting en passant that a hallmark of pseudoscience is often poor quality of language. I am sure you can see what is wrong with this example:

    "They have talked a bit about the two but not really explained it......"

    I shall assume (I think you call that philosophy - I call it a practical application of common sense) that you meant necessary and sufficient.

    I thought the wiki article on these was sufficient.


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  4. #3  
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    Seems like you got on your high horse a little too soon as the TITLE of the post reads: What is the definition of necessary and sufficent evidence

    I thus assumed that whoever had read the title would know what I meant when I said:

    They have talked a bit about the two but not really explained it......
    I did a google for necessary and sufficient evidence so it didn't pop up with your link, so thanks.
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  5. #4  
    Universal Mind John Galt's Avatar
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    Quote Originally Posted by Synergy
    Seems like you got on your high horse a little too soon .
    I have never got off my high horse. The view from up here is superior. Also, I never read titles.

    Quote Originally Posted by Synergy
    I thus assumed that whoever had read the title would know what I meant when I said:
    They have talked a bit about the two but not really explained it......
    I remain troubled by your mixture of singular and plural.

    Quote Originally Posted by Synergy
    I did a google for necessary and sufficient evidence so it didn't pop up with your link, so thanks.
    You are welcome. I just googled "necessary and sufficient" and the wiki article was the first hit.
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  6. #5  
    Forum Masters Degree organic god's Avatar
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    I remain troubled by your mixture of singular and plural.
    The Ophiolite is a fascinating creature of study, it uses wikipedia to maintain an illusion of intelligence combined with sarcasm to veil its complete lack of knowledge.

    This leads to interesting and entertaining delusions where it believes itself superior to other creatures on the internet.

    The defence mechanism is particularly outstanding, as soon as it finds itself criticised or is afraid that its total ignorance has been discovered, it seeks to criticise the grammar and syntax of the attacker. A curious if somewhat pathetic strategy.
    everything is mathematical.
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  7. #6  
    WYSIWYG Moderator marnixR's Avatar
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    and your qualifications to pronounce yourself about people you don't know at all would be ?
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  8. #7  
    Forum Masters Degree organic god's Avatar
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    just the logical conclusions of a small study based on evidence from the forum itself
    everything is mathematical.
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  9. #8  
    Universal Mind John Galt's Avatar
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    Dear Organic God,

    thank you for taking the time out of your busy day to utterly screw up your assessment of my contribution to your thread. Let's examine - in the spirit of lighthearted antagonism, concealing an underlying camraderie - some of your more obvious errors.

    You suggest my total ignorance has been discovered. If you care to waste your time in looking through a multitude of my posts (a lot of chaff, not much wheat) you would discover that I am quite knowledgeable in some aspects of geology and biology. Perhaps you meant my ignorance in relation to this thread. I'll work on that assumption.

    Can you tell me where I express that I am knowledgeable about the terminology necessary and sufficient? I've carefully re-read my posts and nowhere do I make such a claim, implicitly or explicitly. Indeed, for the record, although I have frequently encountered the phrase, I have never properly understood it. i.e. for proper understanding of a topic I should be able to explain it to another without resorting to any reference material other than to check a detail, or a specific number.

    If I had properly understood it I would have given you an explanation in my words, not offered a reference to wikipedia.

    You seem to think my offering was intended to make me look intelligent. :? That's a strange idea. I was intrigued by your question. I realised that while I had a vague notion of the phrase necessary and sufficient I did not properly understand it. So I went looking. The wikipedia article did a good job of explaining it to me. I hoped it might do the same for you. So this thread was a perfect example of why I frequent the forum. It gave me the opportunity to learn something and the opportunity to share that knowledge with others.

    Finally, you say I resort to attacks on people's grammar when I am criticised. Bollocks. I attacked your grammar from the outset, before you crticised me. I routinely attack bad grammar and slovenly English, except when I believe the perpetrator to be working in a foreign language.

    Warmest regards,
    A Fascinating Creature of Study
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  10. #9 Re: What is the definition of necessary and sufficent eviden 
    Forum Isotope Bunbury's Avatar
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    Quote Originally Posted by Synergy
    I am reading a book on pseudo science and in a passage I just read it says:

    In the example above, people are most influenced by the number (and salience) of couples who adopt and subsequently conceive. In so doing, people implicitly confuse necessary and sufficient evidence: They seem to be reasoning that if there are a fair number of such positive cases, then the phenomenon must exist, or the relationship must be valid.
    They have talked a bit about the two but not really explained it such that I understand the difference properly. I also did a google but didn't find a neat definition of either.

    Could someone who understands what they mean define the two for me in clear terms please.
    I think your confusion comes from two causes: the sentences in the quote box are very badly constructed and confusing in themselves; and "necessary and sufficient" do not really apply to evidence. They are adjectives that are usually applied to conditions or causes. The quoted sentences make no sense to me and it looks as if "necessary and sufficient" are wrongly used. No wonder you are confused.
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  11. #10  
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    Necessary means necessary and sufficient means sufficient.

    In the example given, there is apparently a belief among some that adopting a child enhances the probability of conception by the adopting couple. A large number of examples would be necessary to prove the point but not sufficient.
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