Univerzitet u Berkliju ima neke besplatne kurseve na Internetu, pa vam prenosim jedan deo jedne lekcije jednog od tih kurseva :). Odnosi se na često korišćene (namerno ili nenamerno) kvazizaključke na osnovu nekih pretpostavki. Ne zamerite što nije prevedeno, nije mnogo težak engleski, može dosta da se razume, a sad nemam vremena da prevodim – prosto želim da što pre podelim sa vama. Ali ako bude zahteva, prevešću… Autor predavanja je profesor Philip B. Stark („…Professor of Statistics at University of California, Berkeley where he developed the university’s first online course…“). Na ovu temu ima (na srpskom) vrlo interesantna knjiga Eristička dijalektika, Artura Šopenhauera.
Example 2-1: Ad hominem (personal attack)
Nancy claims the death penalty is a good thing. But Nancy once set fire to a vacant warehouse. Nancy is evil. Therefore, the death penalty is a bad thing.
This argument does not address Nancy’s argument, it just says she must be wrong (about everything) because she is evil. Whether Nancy is good or evil is irrelevant: It has no bearing on whether her argument is sound.
This is a fallacy of relevance: It establishes that Nancy is bad, then equates being bad and never being right. In symbols, the argument is If A then B. A. Therefore C. (If somebody sets fire to a vacant warehouse, that person is evil. Nancy set fire to a vacant warehouse. Therefore, Nancy’s opinion about the death penalty is wrong.)
Ad hominem is Latin for „towards the person.“ An ad hominem argument attacks the person making the claim, rather than the person’s reasoning. A variant of the ad hominem argument is „guilt by association.“ [+]
Example 2-2: Bad motive
Bob claims the death penalty is a good thing. But Bob’s family business manufactures caskets. Bob benefits when people die, so his motives are suspect. Therefore, the death penalty is a bad thing.
This argument does not address Bob’s argument, it addresses Bob’s motives. His motives are irrelevant: They have nothing to do with whether his argument for the death penalty is sound.
This is related to an ad hominem argument. It, too, addresses the person, not the person’s argument. However, rather than condemning Bob as evil, it impugns his motives in arguing for this particular conclusion.
Example 2-3: Tu quoque (look who’s talking)
Amy says people shouldn’t smoke cigarettes in public because cigarette smoke has a strong odor. But Amy wears strong perfume all the time. Amy is clearly a hypocrite. Therefore, smoking in public is fine.
This argument does not engage Amy’s argument: It attacks her for the (in)consistency of her opinions in this matter and in some other matter. Whether Amy wears strong fragrances has nothing to do with whether her argument against smoking is sound.
The abstract form of this argument is also a non sequitur: If A then B. A. Therefore C. (In words: If you complain about strong smells and wear strong fragrances, you are a hypocrite. Amy complains about strong smells and wears strong perfume; therefore, her opinion about smoking is incorrect.)
Tu quoque is Latin for „you also.“ It related to ad hominem arguments: it addresses the person rather than the person’s argument. But instead of generally condemning the other party, it says that his or her claim in the matter at issue is hypocritical because it is inconsistent with something else the person has done or said. We are supposed to conclude that he or she must therefore be wrong on this particular point.
Example 2-4: Two wrongs make a right
Yes, I hit Billy. But Sally hit him first.
This argument claims it is fine to do something wrong because somebody else did something wrong. The argument is of the form: If A then B. A. Therefore C. (In words: If Sally hit Billy, it’s OK for Billy to hit Sally. Sally hit Billy. Therefore, it’s OK for me to hit Billy.)
Generally, the two-wrongs-make-a-right argument says that the justified wrong happened after the exculpatory wrong, or was less severe. For instance, Sally hit Billy first, or Sally hit Billy harder than I did, or Sally pulled a knife on Billy.
On the other hand, it might be quite reasonable to argue, „yes, I hit Billy. But he was beating me with a baseball bat—I acted in self defense. “ In that case, the first „wrong“ might justify hitting Billy, which otherwise would be wrong.
Example 2-5: Ad baculum (appeal to force)
If you don’t give me your lunch money, my big brother will beat you up. You don’t want to be beaten up, do you? Therefore, you should give me your lunch money.
This argument appeals to force: Accept my conclusion—or else. It is not a logical argument. [+]
It is an argument that if you do not accept the conclusion (and give me your lunch money), something bad will happen (you will get beaten)—not an argument that the conclusion is correct. The form of the argument is If A then B. B is bad. Therefore, not A. Here, A is „you don’t give me your lunch money,“ B is „you will be beaten up.“ The argument conflates „it is bad to be beaten up“ with „it is false that you will be beaten up.“ The argument establishes the conclusion that if you don’t give me your lunch money, something bad will happen. It does not establish the conclusion that you should give me your lunch money. There is a missing premise that relates the implicit conclusion that could be justified on the evidence (the if you don’t give me your lunch money, something bad will happen) to the stated conclusion (you should give me your lunch money). Ad baculum is a fallacy of relevance, because it relies on a non sequitur of relevance.
Ad baculum is Latin for „to the stick.“ It is essentially the argument „might makes right.“
Not all arguments of the form If you do A then B will happen. B is bad. Therefore, don’t do A are ad baculum arguments. It depends in part on whether B is a real or imposed consequence of A. For instance, If you cheat on your exam, you will feel guilty about it for the rest of your life; therefore, you should not cheat is not an ad baculum argument. But If you cheat on your exam, I will turn you in to the Student Conduct Office and have you expelled; therefore, you should not cheat is an ad baculum argument. (Either way, don’t cheat on your exam!)
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PS. Nisu me uhapsili zbog prethodnog teksta 🙂 (bar ne još :))