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  1. #1
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    Biased Choice of Evidence; A Logical Fallacy?

    Here is a hypothetical situation:

    Person A is arguing in favor of X. X has many respected supporters within the scientific community. X also, however, has many respected opponents within the scientific community. Person A defends the argument in favor of X by quoting all of these scientific studies in favor of X. These supporters in no, way, shape, or form have based any of their evidence on any moral and/or political bias. All of their research is based on sound, objective experimentation. However, Person A either outright ignores, or writes off the arguments of X's opponents with little argumentation.

    Is Person A committing a logical fallacy?

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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by czahar View Post
    Here is a hypothetical situation:

    Person A is arguing in favor of X. X has many respected supporters within the scientific community. X also, however, has many respected opponents within the scientific community. Person A defends the argument in favor of X by quoting all of these scientific studies in favor of X. These supporters in no, way, shape, or form have based any of their evidence on any moral and/or political bias. All of their research is based on sound, objective experimentation. However, Person A either outright ignores, or writes off the arguments of X's opponents with little argumentation.

    Is Person A committing a logical fallacy?
    No, there's nothing wrong with his logic, just his methods. He should try and refute the opponents, rather than ignore them.

  3. #3
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by The Great Khan View Post
    No, there's nothing wrong with his logic, just his methods. He should try and refute the opponents, rather than ignore them.
    Makes sense. But going by that logic, should the Biased Sample fallacy be stricken from the list of logical fallacies? After all, is their any difference between using biased evidence, and a biased choice of evidence?

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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by czahar View Post
    Makes sense. But going by that logic, should the Biased Sample fallacy be stricken from the list of logical fallacies? After all, is their any difference between using biased evidence, and a biased choice of evidence?
    I wouldn't consider the Biased Sample Fallacy to be a logical fallacy.
    "I am against religion because it teaches us to be satisfied with not understanding the world" - Richard Dawkins

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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by Allocutus View Post
    I wouldn't consider the Biased Sample Fallacy to be a logical fallacy.
    What kind of fallacy would you classify it under?

  6. #6
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    I agree with the current opinions that the situation presented is not a Logical (i.e. a "formal") fallacy. It is a rhetorical fallacy that should be easily overcome by a well-informed opponent who is acquainted with the studies that Person A has ignored. If Person A has not bothered to devise rebuttals for the points presented, when Person B introduces the oppositional studies, Person A will quickly lose the debate. He has not, however, committed a logical fallacy simply by the action of collecting objectively valid supporting points.

  7. #7
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by czahar View Post
    What kind of fallacy would you classify it under?
    It's just a bad argument. Fallacies generally concern themselves with arguments where the premises don't logically support the conclusion.
    "I am against religion because it teaches us to be satisfied with not understanding the world" - Richard Dawkins

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  8. #8
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by czahar View Post
    Here is a hypothetical situation:

    Person A is arguing in favor of X. X has many respected supporters within the scientific community. X also, however, has many respected opponents within the scientific community. Person A defends the argument in favor of X by quoting all of these scientific studies in favor of X. These supporters in no, way, shape, or form have based any of their evidence on any moral and/or political bias. All of their research is based on sound, objective experimentation. However, Person A either outright ignores, or writes off the arguments of X's opponents with little argumentation.

    Is Person A committing a logical fallacy?
    Yes.


    If a source is biased, by which I mean that the source only pays attention to specific evidence, it means that they're ignoring evidence (this is a inductive logical fallacy, btw).

    Ignoring valid evidence is the informal fallacy of "one-sidedness." So citing a biased study is an example of the one-sidedness fallacy.

    http://www.fallacyfiles.org/onesided.html

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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by czahar View Post
    Here is a hypothetical situation:

    Person A is arguing in favor of X. X has many respected supporters within the scientific community. X also, however, has many respected opponents within the scientific community. Person A defends the argument in favor of X by quoting all of these scientific studies in favor of X. These supporters in no, way, shape, or form have based any of their evidence on any moral and/or political bias. All of their research is based on sound, objective experimentation. However, Person A either outright ignores, or writes off the arguments of X's opponents with little argumentation.

    Is Person A committing a logical fallacy?
    No.

    Logical proof cannot exist when there can be unknown premises. Empiricism, by definition, always contains the possibility for such.
    “When men hire themselves out to shoot other men to order, asking nothing about the justice of their cause, I don’t care if they are shot themselves."

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  10. #10
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by Autolykos View Post
    No.

    Logical proof cannot exist when there can be unknown premises. Empiricism, by definition, always contains the possibility for such.
    This is, of course, utter tosh, categorically wrong, and not what the OP was asking about. Logical proof can always exists, even if the premises are utter ********. Logic is about the structure of valid logical inferences. Valid arguments can lead to false conclusions, because it only cares about the structure of the argument, not the premises. Soundness, which is a product of inductive and deductive reasoning, is never an actual "proof."


    Regardless, inductive reasoning has formal fallacies which dictate the rules for valid statistical inferences (probabilistic inferences) and inductive arguments. The article I gave above outlined a statistical fallacy for inductive reasoning, which is what the OP is asking about.

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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by GoldPhoenix View Post
    This is, of course, utter tosh, categorically wrong, and not what the OP was asking about. Logical proof can always exists, even if the premises are utter [nonsense].
    How about I put it another way?

    Logical proof requires a closed set of premises. If one treats the set of premises as open, then logical proof, strictly speaking, cannot come about.

    Logic is about the structure of valid logical inferences.
    Circular reasoning, obviously.

    Valid arguments can lead to false conclusions, because it only cares about the structure of the argument, not the premises. Soundness, which is a product of inductive and deductive reasoning, is never an actual "proof."
    Then we simply have different definitions of "proof", as I equate the term with "demonstration of (logical) soundness", whereas you seem to equate it with something else. To be honest, I'm not sure what that something else is.

    Regardless, inductive reasoning has formal fallacies which dictate the rules for valid statistical inferences (probabilistic inferences) and inductive arguments. The article I gave above outlined a statistical fallacy for inductive reasoning, which is what the OP is asking about.
    Quoting from the Wikipedia article on inductive reasoning:

    The premises of an inductive logical argument indicate some degree of support (inductive probability) for the conclusion but do not entail it; i.e. they do not ensure its truth. [Emphasis added.]
    Although I would prefer to use "evaluation to a particular value" for "truth" in the emphasized section above, the point remains. As far as I'm concerned (i.e. given my semantics), "a proof which does not ensure evaluation to a particular value" is not a proof at all. How can one say that there is actual logical soundness to an inductive argument? The set of premises to be considered is inherently open and must remain open.
    “When men hire themselves out to shoot other men to order, asking nothing about the justice of their cause, I don’t care if they are shot themselves."

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  12. #12
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by Autolykos View Post
    How about I put it another way?

    Logical proof requires a closed set of premises. If one treats the set of premises as open, then logical proof, strictly speaking, cannot come about.
    I assume you're not talking about an actual open set or closed set, because there's no need to include topology into this.


    Quote Originally Posted by Auto
    Circular reasoning, obviously.
    ... Seriously?

    It's circular reasoning to define logic as the study of study of deductive/logical inferences?


    Quote Originally Posted by Auto
    Then we simply have different definitions of "proof", as I equate the term with "demonstration of (logical) soundness", whereas you seem to equate it with something else. To be honest, I'm not sure what that something else is.
    Yes, we have a different set of definitions. I'm using the standard, academic definitions of logic. You're using the definitions that you make up when you debate.

    A valid argument is an argument which follows necessarily from its premises.

    A sound argument is an argument which both follows necessarily from its premises and it's premises are (reasonably) true.



    From the John Carroll University philosophy department website: http://www.jcu.edu/philosophy/gensler/fe/fe-0--0b.htm


    Quote Originally Posted by Auto
    Quoting from the Wikipedia article on inductive reasoning:

    "The premises of an inductive logical argument indicate some degree of support (inductive probability) for the conclusion but do not entail it; i.e. they do not ensure its truth." [Emphasis added.]

    Although I would prefer to use "evaluation to a particular value" for "truth" in the emphasized section above, the point remains. As far as I'm concerned (i.e. given my semantics), "a proof which does not ensure evaluation to a particular value" is not a proof at all. How can one say that there is actual logical soundness to an inductive argument? The set of premises to be considered is inherently open and must remain open.
    I'm just going to ignore this because you've done nothing more than say: "Yes, GP, I agree with you!" The main point of disconnect, I presume, comes from the previous point of you not understanding the difference between sound and valid arguments.

    ---------- Post added at 04:16 PM ---------- Previous post was at 04:12 PM ----------

    Quote Originally Posted by Allocutus View Post
    I wouldn't consider the Biased Sample Fallacy to be a logical fallacy.
    Well, most of the time people fail to recognize the different between deductive reason and inductive reason.

    Very often, people will simply subsume the two together under logical fallacies, even if the fallacy is related to inductive, and not deductive, reasoning.


    It's unfortunate, but it's pretty common practice, as far as I can tell.

  13. #13
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by GoldPhoenix View Post
    I assume you're not talking about an actual open set or closed set, because there's no need to include topology into this.
    ... Of course not.

    Are you implying that I'm somehow not allowed to use the term "open set" to refer to something outside of topology, or are you simply asking for clarification here?

    ... Seriously?

    It's circular reasoning to define logic as the study of study of deductive/logical inferences?
    Yes, because it's circular reasoning to define a term such that the term itself is included in the definition.

    Yes, we have a different set of definitions. I'm using the standard, academic definitions of logic. You're using the definitions that you make up when you debate.
    Assuming for the moment that there is a broad, scholarly consensus on what constitute "the standard, academic definitions of logic", how does that take away from my argument? Better yet, how does it disprove my argument?

    A valid argument is an argument which follows necessarily from its premises.

    A sound argument is an argument which both follows necessarily from its premises and it's premises are (reasonably) true.
    I understand that you are proposing certain terms with their definitions here.

    Allow me to provide a translation between your definitions and my own. As far as I'm concerned, (formal or pure) logic concerns validity only. There is no constraint on (formal or pure) logic such that premises must be ("reasonably") true. What I call empiricism has that constraint, however.

    So, as far as I'm concerned, a logical fallacy is any argument where the conclusion does not follow from the premises. To use your terminology, I consider all logical fallacies to be fallacies of validity only. "Fallacies of soundness" are what I would call empirical fallacies.

    I'm just going to ignore this because you've done nothing more than say: "Yes, GP, I agree with you!" The main point of disconnect, I presume, comes from the previous point of you not understanding the difference between sound and valid arguments.
    Of course I do understand the difference between what you call sound and valid arguments. I simply use different terms/definitions for them. Hopefully I've demonstrated above that your terms can be translated into mine and vice-versa.
    “When men hire themselves out to shoot other men to order, asking nothing about the justice of their cause, I don’t care if they are shot themselves."

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  14. #14
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by Autolykos View Post
    Yes, because it's circular reasoning to define a term such that the term itself is included in the definition.
    Actually, it's categorically not a circular reasoning. Defining something is making a definition, not a logical argument; therefore, you cannot call it circular reasoning. It's just a somewhat tenuous definition, which requires a second definition. As long as I give a definition of what a logical inference is, which is a conclusion which must follow from the premises, then it's not even tenuous.

    Quote Originally Posted by Auto
    Assuming for the moment that there is a broad, scholarly consensus on what constitute "the standard, academic definitions of logic", how does that take away from my argument? Better yet, how does it disprove my argument?
    It takes away from your argument because you're being ambiguous, and therefore reckless, with your diction, and, because of this, you're equivocating.

    You're jumping into a thread and submitting your own definition of the word "valid," "sound," and "proof." Then you tell other people that they're not using your definitions, therefore what they're saying is wrong (if they were using your definitions... which they are not). Hence, you're equivocating. You do it a lot, Auto, by playing these word games that you're so fond of.


    Quote Originally Posted by auto
    I understand that you are proposing certain terms with their definitions here.

    Allow me to provide a translation between your definitions and my own. As far as I'm concerned, (formal or pure) logic concerns validity only. There is no constraint on (formal or pure) logic such that premises must be ("reasonably") true. What I call empiricism has that constraint, however.
    This is correct, to a degree. Empiricism actually refers to the philosophy that a posteriori knowledge is the best form of knowledge, but this is correct. Inductive fallacies or statistical fallacies are more dealing with your notion of "empiricism", however.

    But yes, logical fallacy refers to only deductive (validity). The problem is, again, so few people recognize the difference between them, that it is pointless (on an internet forum) to distinguish them. Yes, technically this is not a logical fallacy. Yes, this is a fallacy. Arguing over the adjective is not worth while.

    Quote Originally Posted by Auto
    So, as far as I'm concerned, a logical fallacy is any argument where the conclusion does not follow from the premises. To use your terminology, I consider all logical fallacies to be fallacies of validity only. "Fallacies of soundness" are what I would call empirical fallacies.

    Of course I do understand the difference between what you call sound and valid arguments. I simply use different terms/definitions for them. Hopefully I've demonstrated above that your terms can be translated into mine and vice-versa.
    You should move over to the standard definitions.

  15. #15
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Surely this can't be so hard that people of average intelligence couldn't comprehend it, if explained.
    "I am against religion because it teaches us to be satisfied with not understanding the world" - Richard Dawkins

    "If you could rationalize with Religious people there would be no more Religious people" -Gregory House

  16. #16
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by GoldPhoenix View Post
    Actually, it's categorically not a circular reasoning. Defining something is making a definition, not a logical argument; therefore, you cannot call it circular reasoning. It's just a somewhat tenuous definition, which requires a second definition. As long as I give a definition of what a logical inference is, which is a conclusion which must follow from the premises, then it's not even tenuous.
    Would you consider the following to be a definition or a logical argument?

    A =/= A

    It takes away from your argument because you're being ambiguous, and therefore reckless, with your diction, and, because of this, you're equivocating.
    Have I not clearly defined my terms? If I have (as I believe), then where is the ambiguity, let alone the recklessness?

    Equivocation (as far as I understand it) only applies within an argument. As I seem to have used my terms consistently in this thread, where is the equivocation?

    You're jumping into a thread and submitting your own definition of the word "valid," "sound," and "proof." Then you tell other people that they're not using your definitions, therefore what they're saying is wrong (if they were using your definitions... which they are not). Hence, you're equivocating. You do it a lot, Auto, by playing these word games that you're so fond of.
    Sorry, where did I claim that, because other people are not using my definitions, that therefore what they're saying is wrong? As far as I can tell, I have not said that. What I have merely pointed out is that they are using different definitions. It's not so much a matter of right vs. wrong, then, as it is a matter of mere difference. Does that make sense? I don't see why I can't simply point out the difference where I see it.

    This is correct, to a degree. Empiricism actually refers to the philosophy that a posteriori knowledge is the best form of knowledge, but this is correct. Inductive fallacies or statistical fallacies are more dealing with your notion of "empiricism", however.
    You understood what I meant by "empiricism", right? I believe I gave a sufficiently precise definition. So if you did understand it, what is the big deal?

    But yes, logical fallacy refers to only deductive (validity). The problem is, again, so few people recognize the difference between them, that it is pointless (on an internet forum) to distinguish them. Yes, technically this is not a logical fallacy. Yes, this is a fallacy. Arguing over the adjective is not worth while.
    Thank you for admitting that biased choice of evidence is not a fallacy of deduction/validity (what we both call a "logical fallacy").

    With that said, the subject line of this thread is not "Biased Choice of Evidence; A Fallacy?" but instead "Biased Choice of Evidence; A Logical Fallacy?" I took that to mean a fallacy of deduction. Perhaps Czahar meant something different. Why don't we ask him?

    In any case, I don't see how we're arguing over the adjective. I certainly am not.

    You should move over to the standard definitions.
    To quote Bartleby, "I would prefer not to."
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  17. #17
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    I think it may be fallacious, however, the actual arguments would need to be seen to make such a determination. I think it would be much easier and more correct to accuse such a person of cognitive bias. This, by itself, is not a fallacy, as a fallacy is in the construction of the argument, not in the bias of the individual. Certainly bias leads to fallacy, but it can lead to many. We would need to see each argument to define them.
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  18. #18
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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by GP
    Actually, it's categorically not a circular reasoning. Defining something is making a definition, not a logical argument; therefore, you cannot call it circular reasoning. It's just a somewhat tenuous definition, which requires a second definition. As long as I give a definition of what a logical inference is, which is a conclusion which must follow from the premises, then it's not even tenuous.
    Every definition of a word is given by a set of other words, each of which are defined by a set of other words, each of which &c.

    How is that not circular logic, or at least infinite recursion?

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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by czahar View Post
    Here is a hypothetical situation:

    Person A is arguing in favor of X. X has many respected supporters within the scientific community. X also, however, has many respected opponents within the scientific community. Person A defends the argument in favor of X by quoting all of these scientific studies in favor of X. These supporters in no, way, shape, or form have based any of their evidence on any moral and/or political bias. All of their research is based on sound, objective experimentation. However, Person A either outright ignores, or writes off the arguments of X's opponents with little argumentation.

    Is Person A committing a logical fallacy?
    Yes,

    "A" clearly commits a fallacious appeal to authority since "X" has many respected opponents within the scientific community.

    For an appeal to authority to be proper....
    There [needs to be] an adequate degree of agreement among the other experts in the subject in question.

    If there is a significant amount of legitimate dispute among the experts within a subject, then it will fallacious to make an Appeal to Authority using the disputing experts. This is because for almost any claim being made and "supported" by one expert there will be a counterclaim that is made and "supported" by another expert. In such cases an Appeal to Authority would tend to be futile. In such cases, the dispute has to be settled by consideration of the actual issues under dispute. Since either side in such a dispute can invoke experts, the dispute cannot be rationally settled by Appeals to Authority.

    Link to source



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    Re: Biased Choice of Evidence; A Logical Fallacy?

    Quote Originally Posted by CliveStaples View Post
    Every definition of a word is given by a set of other words, each of which are defined by a set of other words, each of which &c.

    How is that not circular logic, or at least infinite recursion?
    I'm surprised you didn't cover this in one of your math courses.


    Ultimately, you just accept something (or things) as a "primitive notion." Using two math examples, the two primitive notions in abstract algebra are sets and relations; in topology, it's the primitive notions are open sets, et alii.
    "Those who can make you believe absurdities, can make you commit atrocities." --Voltaire

 

 
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