Fallacies of Relevance

-When an argument relies on premisses that are not relevant to its conclusion, the fallacy committed is the fallacy of relevance. The term non sequitur ("does not follow") is also often applied to all the fallacies of relevance because the gap between the premisses and the conclusion is very wide and the claim that the conclusion does follow from the premises is an obvious mistake.

    1. Argument from Ignorance: Argument Ad Ignorantiam. The argument ad ignorantiam (from ignorance) is the fallacy that is committed when it is argued that a proposition is true simply because it has not been proved false, or that it is false because it has not been proved true. This fallacious appeal to ignorance  occurs when in criticism of an argumentw whose propositions cannot yet be established as true or proven true with absolute certainty: these arguments are mistakenly on the ground that they can can not be proven true held to be false because they cannot be proven true.

    2. The Appeal to Inappropriate Authority: Argument Ad Verecundiam.  An argument commits the fallacy of the appeal to inappropriate authority (ad verecundiam) when the argument is based on an appeal to the opinion of someone who has no legitimate claim to authority to the topic being discussed. Clear examples of inappropriate appeals to authority appear in advertising "testimonials:" famous athletes endorsing products that have nothing to do with their area of competence on the basketball court or the football field.

    3.) Argument Ad Hominem: means “against the person.” Ad Hominem arguments are arguments that are offered as a rejection or refutation on another person’s argument. But the person committing the ad Hominem fallacy does not offer reasons to reject the other person’s conclusion but attacks the person who asserts or denies a conclusion. There are two forms or types of Ad Hominem “arguments:” 1.) Ad Hominem, abusive and 2.) Ad Hominem, circumstantial.
Arguments ad Hominem, abusive belittles the character of their opponent by denying their reasonableness or their integrity, or their moral character. To argue that a proposal is bad because it was proposed by radicals (member of KKK or Students for Democratic Society) is the clearest example of this argument.
Arguments ad Hominem, circumstantial. The circumstances of the person holding an opinion have no relevance to the truth or falsity his opinion. A politican must hold a particular belief for it was adopted as part of the platform of his party. A minister must hold a particular opinion for it is denial is incompatible with scripture. The tu quoque (you are another or you also do it) is a variety of the circumstantial ad hominem argument; for example the hunters accused of needless killing of animals replies that the person that makes this argument eats harmless animals (eats meat).

    4. The Appeal to Emotion: Argument Ad Populum.  Argument ad populum (literally appeal "to the people," and by implication to easily aroused emotions of the crowd or majority) is often used by public speakers including politicians. These appeals to the emotions of the crowd are fallacious because they replace the responibility of presenting evidence and rational argument in clear non-emotional language with expressive or emotional language designed and calculated to excite enthusiasm, excitement for their proposal and anger or hatred for the speaker's opponent and his proposal. Advertising relies heavily on arguments ad populum when an add associates the product with things we yearn for or that excites our favor.

    5. The Appeal to Pity: Argument Ad Misericordiam Copi thinks of appeal to pity as a speical case of appeal to emotion. This appeal is committed so often it is good to give it its own name. The appeal to pity viewed as a special case of the appeal to emotion in which mercy or "pitying heart"of the audience is appealed to by the speaker to get the audience to agree with his proposal. "In criminal trials, although jury sympathy has no bearing on the guilt or innocence of the accused, effective defense attorneys often appeal to the pity of the jury."

    6. The Appeal to Force: Argument Ad Baculum The appeal to force in order to cause an audience to accept some proposal or conclusion is a  fallacy. The use  threats (direct threats or veiled threats to harm an opponent) often occurs when evidence or rational methods fail the speaker to get his way or his proposal accepted. "The appeal to force is the abandonment of reason."

    7. Irrelevant Conclusion: Ignoratio Elenchi. The fallacy of irrelevant conclusion ("mistaken proof") is committed:  an argument states that is aim to establish a particular conclusion but instead the argument is actually directeto to prove a different conclusion. This is the hardest fallacy to identify. Study the examples in the text carefully. The reasoning may seem plausible in because the premises do provide evidence for another conclusion, but yet the argument misfires because it is not a defense of the conclusion in dispute. Any argument that obscures the issue with attractive generalizations about topic than the logical subject of the conclusion commits the ignoratio elenchi. Such arguments often succeed by distracting the attention of the audience.  The speaker, by urgeing with enthusiasm the need for the proposal or objective defended by the premisses,  may succeed in transferring the speaker's enthusiasm for the irrelvant topic of his premises, in the minds of the audience to be presuaded, to the topic not supported by the speaker's  premisses.

    Every fallacy of relevance is, in a sense, an ignoratio elenchi. But Copi uses ignoratio elenchi to mean the fallacy in which the argument misses the point of the conclusion without making one of those other mistakes of the named fallacies of irrelevance that characterizes or defines the other particular fallacies of irrelevance ( appeal to force, appeal to pity, appeal to the people) in which the premisses also are not relevant to the conclusion.

Lecture 22:  Fallacies of Presumption -When unsupportable or obvious false assumptions are hidden in an argument and these dubious premises are crucial for the support of the conclusion, falllacious argument of this kind are called fallacies of presumption. To expose this kind of misguided reasoning,  it is usually enough to call attention to the hidden and false assumptions.
         1. Complex Question - One of the most common fallacies of presumption is the complex question: asking a question which presuppose the truth of some assertion or proposition contained within the question.. "Have you quit beating your wife?" presupposes the assertion that "you have been beating your wife." The complex question is often a deceitful device because the use of a complex question often has the purpose of suggesting the truth of the unstated assertion (or assumption) on which it is built. Whenever a question is accompanied by the demand that it be answered yes or no, there is reason to suspect that the question is a complex question.When a question is complex and all of its assertions or assumptions are to be denied, they must be denied individually: The denial of only one of its assertion may lead to the assumption that the other assertions in the queston are true.
         2. False Cause -  Presuming the reality of a causal connection that does not in fact exist is the mistake called the fallacy of false cause. one kind of false cause is called the fallacy of post hoc ergo propter hoc ("after the thing; therefore, because of the thing").  Often we are tempted to presume that one event is the caused of another because it precedes (confusing temporal succession and causal connection) the other event closely in time.
         3. Begging the Question: (Petitio Principii) - To beg the question is to assume the truth of what one seeks to prove in the effort to prove it.
         4. Accident - A generalization that is true may not apply in a special case, for reasons having to do with the "accidental" circumstances of that case.When we presume that a generalization applies to individual cases that it does not properly govern, we commit the fallacy of accident.
         5. Converse Accident- When we carelessly presume that what is true of a particular case is true of the all cases, we commit the fallacy of converse accident.

Lecture 21: Fallacies of Ambiguity: When the meaning of  a word or a phrases shifts meaning as a result of inattention or deliberate deception within the course of an argument, mistakes of inattention or deception of this kind are called fallacies of ambiguity.
When this fallacy occurs, a term has one meaning in a premiss and quite a different menaing in the conclusion.
        1. The fallacy of amphiboly occurs when one is arguing from premisses whose expression in language are ambiguous because of their grammatical construction: at least two different interpretations of the statement of possible: the amphibolous statement may be true in one interpretation and false in another.The fallacy of amphiboly is committed when an amphibolous statement serves as a premiss with the interpretation that makes it true and a conclusion is drawn from this premise on the interpretation that makes it false.
        2. The fallacy of Accent. An argument may be deceptive and  invalid because there are different interpretations of the premises due to different emphasis a speaker may give to its words or parts that occur in the statements that are the premises and the conclusion. "The fallacy of accent includes the distortion produced by pulling a quoted passage out of context, putting it in another context, and then drawing a conclusion that would not have been drawn in the original context." See Copi. This is an important instance of the fallacy of accent: see his example about advertizing movies.
        3. Fallacy of Composition. There are two kinds of this fallacy. The first kind of fallacies of compositon refers to reasoning fallaciously from the attributes of the parts of a whole to the attributes of the whole itself. The second type of invalid fallacy of composition turns on the distinction between the distributive and the collective use of general terms. A term is used distributively when the term refers to attributes of each member of a group or set of objects individually.In contradistinction, a term is used collectively when a term refers to attributes of the members of the group taken as a group or  whole. See examples in text.
        4. Fallacy of Division. The fallacy of division (same confusion as fallacy of composition) is the reverse (proceeds in the opposite direction) of the fallacy of composition As in the case of composition, two varieties of division should be distinguished. The first kind of fallacy of division consists in arguing that what is true of a whole must also be true of its parts. The second type of the division fallacy is committed "when one argues from the attributes of a collection of elements to the attributes of the elements themselves." Copi says "The fallacy of division, which springs from a kind of ambiguity, resembles the fallacy of accident, which springs from unwarranted presumption. Likewise, the fallacy of composition, also flowing from ambiguity, resembles converse accident, another fallacy of presumption. But these likenesses are superficial." You should be able to clearly explain the likenesses and the differences. Also practice identifing these.

Links
Sixteen fallacies with analyzed examples. (Barry Edward Eckhouse)
Stanford Encyclopedia of Philosophy, Informal Logic
Fallacy Files