Love is a Fallacy謬論

1、Love is a FallacyLove is a FallacyWhat is a fallacy?nA fallacy is the use of poor, or invalid reasoning for the construction of an argument. It is also used to refer to an argument which appears to be correct but is not. nAn argument in logic presents evidence in support of some thesis or conclusion

2、. nAn argument has two components: a conclusion and certain premises.nThe conclusion is said to be drawn or inferred from the premises. nAn argument is deductively valid when its premises provide evidence for the conclusion. nAn argument that fails to be conclusively deduced is invalid, it is said t

3、o be fallacious.ArgumentLogic Fallaciesn1. Dicto Simpliciter（絕對(duì)判斷）n2. Hasty Generalization（輕率歸納）n3. Post Hoc（錯(cuò)誤因果）n4. Contradictory Premises（矛盾前提）1. Dicto SimpliciternPolly, I said gently, the argument is a fallacy. Exercise is good is an unqualified generalization. For instance, if you have heart d

4、isease, exercise is bad, not good. Many people are ordered by their doctors not to exercise. You must qualify the generalization. You must say exercise is usually good, or exercise is good for most people. Otherwise you have committed a Dicto Simpliciter. Do you see? 1. Dicto Simpliciter （絕對(duì)判斷） Dict

5、o Simpliciter is an argument based on an unqualified generalization. The argument applies a general rule to a particular case in which some special circumstances make the rule inapplicable. ExamplesnWomen are on average not as strong as men and less able to perform well politically. Therefore, women

6、 cant pull their weight in government work.n雖然女性確實(shí)在政界擔(dān)任較少工作，但這不意味著女性群體中所有的人都是這樣。nJapanese waged a war to Chinese, which had nothing to do with humanity but everything to do with aggression. Therefore every Japanese is guilty and should be condemned.n雖然日本侵華的邪惡戰(zhàn)爭(zhēng)任歷歷在目，但并不是所有的日本人都有罪，都應(yīng)該受到譴責(zé)。2. Hasty Ge

7、neralizationnNext we take up a fallacy called Hasty Generalization. Listen carefully: You cant speak French. Petey Burch cant speak French. I must therefore conclude that nobody at the University of Minnesota can speak French. nReally? said Polly, amazed. Nobody? nI hid my exasperation. Polly, its a

8、 fallacy. The generalization is reached too hastily. There are too few instance to support such a conclusion. n2. Hasty Generalization（輕率歸納）nHasty generalization is a fallacy in which a conclusion is not logically justified by sufficient or unbiased evidence.nA hasty generalization always proceeds f

9、rom the particular to the general.Hasty GeneralizationnIts pattern: X is true for A. X is true for B. X is true for C. X is true for D. Therefore, X is true for E, F, G, etc.Example Mike failed biology exam. Jane failed biology exam. Maria failed biology exam. Therefore,I conclude that most students

10、 who take biology exam will fail it.Analysis nIn understanding and characterizing general situations, a logician cannot normally examine every single example. However, the examples used in inductive reasoning should be typical of the problem or situation at hand. Maybe Mike, Jane, and Maria are exce

11、ptionally poor students. Maybe they were sick and missed too many lectures. If a logician wants to make the case that most students will fail biology exam, she should n(a) get a very large sample-at least one larger than three or n(b) if that isnt possible, she will need to go out of his way to prov

12、e to the reader that her three samples are somehow representative of the norm.3. Post HocnListen to this: Lets not take Bill on our picnic. Every time we take it out with us, it rains. nI know somebody just like that, she exclaimed. A girl back home - Eula Becker, her name is. It never fails. Every

13、single time we take her on a picnic. nPolly, I said sharply, its a fallacy. Eula Becker doesnt cause the rain. She has no connection with the rain. You are guilty of Post Hoc if you blame Eula Becker. n3. Post Hoc（錯(cuò)誤因果）nPost Hoc is a fallacy in which one event is said to be the cause of a later even

14、t simply because it occurred earlier.n Post Hoc is a fallacy with the following form:n 1.A occurs before B.n 2.Therefore A is the cause of B.ExamplesnJoan is scratched by a cat while visiting her friend. Two days later she comes down with a fever. Joan concludes that the cats scratch must be the cau

15、se of her illness.nMost young criminals watch violent movies before they commit their crimes; obviously, violent movies lead to juvenile delinquency.n甲事情發(fā)生在乙事情之前，這并不代表著先發(fā)生的甲事情就是后發(fā)生的乙事情的原因。 4. Contradictory PremisesnIf God can do anything, can He make a stone so heavy that He wont be able to lift it?

16、 nOf course, she replied promptly. nBut if He can do anything, He can lift the stone, I pointed out. nYeah, she said thoughtfully. Well, then I guess He cant make the stone. nBut He can do anything, I reminded her. nShe scratched her pretty, empty head. Im all confused, she admitted. nOf course you

17、are. Because when the premises of an argument contradict each other, there can be no argument. If there is an irresistible force, there can be no immovable object. If there is an immovable object, there can be no irresistible force. Get it? n4. Contradictory Premises（矛盾前提）nContradictory Premises is

18、an argument that draws a conclusion from inconsistent or incompatible premises.nEssentially, a proposition is contradictory when it asserts and denies the same thing.nSometimes it is difficult to distinguish between real and apparent incompatible premises.nLets look at the example below.nA father said