The so-called syllogism refers to the reasoning that a homonym connects two blunt propositions as a premise and draws a new blunt proposition as a conclusion. A syllogism consists of three outspoken propositions, two of which are premises and one is conclusion. The major item of the conclusion is the minor item (represented by S), and the premise of including the minor item is the minor premise; The predicate of the conclusion is the major term (expressed by P), and the premise of including the major term is the major premise; Two premises * * * Some terms are called neutral terms (denoted by m). For example, all truths are correct; Darwin's theory of evolution is truth; Therefore, Darwin's theory of evolution is correct. This is a syllogism. Its two premises contain a word "truth" with the same meaning, and with this word as the intermediary, the two propositions of "all truth is correct" and "Darwin's theory of evolution is truth" are linked, and the conclusion that "Darwin's theory of evolution is correct" is deduced. In this syllogism, "correct"> In order to make syllogism effective, we must abide by the general rules. The general rules of syllogism are as follows: Rule 1: In a syllogism, there can only be three different terms. In fact, syllogism is the relationship between the middle term (M) and the big term (P) and the small term (S) respectively, so as to draw a conclusion about the relationship between the small term and the big term. We can't draw any conclusions. It is in this sense that we say that the term is a bridge or medium connecting the major events and the minor events. Only when the three concepts appear twice can three propositions be formed, and no more or less than three concepts can form three propositions. The common situation of "four-word item error" or "four-concept error" is that the words in the major premise and the minor premise as the middle item look the same. Therefore, this syllogism actually contains four different terms. Strictly speaking, there is no middle term, so there is no bridge and medium connecting the big term and the small term, and the conclusion is not inevitable. This kind of error is called "four-word terminology error" or "four-concept error". Rule 2: The item in the premise must be GAI at least once. The syllogism draws a conclusion by virtue of the bridge and intermediary in the premise. That is, at least one of events and events is related to all events, and the other is related to some or all events to ensure that there is a certain relationship between events. Otherwise, events and events are only related to some events, so it is possible that events are related to this part of events and events are related to another part of events. Therefore, there is no relationship between events. Xiao Zhang is a teacher; So, (). This syllogism can't reach a definite conclusion. The reason is that "teacher", as a Chinese word, has no GAI in the premise (both premises only conclude that "professor" and "Xiao Zhang" are part of "teacher"), so the relationship between "Xiao Zhang" and "professor" cannot be determined, and it is impossible to draw an inevitable conclusion. This reasoning is illogical. Rule 3: Items that are not GAI in the premise are not GAI in the conclusion. The logical mistake made in violation of this rule is "improper GAI", which can be manifested in two forms: "improper GAI in minor events" and "improper GAI in major events". For example, cherry blossoms are plants; Lilacs are not cherry blossoms; So, cloves are not plants. In this syllogism, the event "planting" is not that GAI is in the major premise, but that GAI made the mistake of "improper GAI of the event" or "improper expansion of the event" in the conclusion. Rule 4: No clear conclusion can be drawn from two negative premises. If both premises are negative, it means that neither the primary term nor the secondary term intersects at least part or all of the intermediate term. In this way, there is no guarantee that the primary term and the secondary term are interrelated because they intersect with the same part of the intermediate term. The middle term can't be used as a bridge to connect the big term and the small term, and there may be various relationships between the big term and the small term itself, so a definite conclusion can't be drawn. Rule 5: ① If one of the two premises is negative, then the conclusion is negative. If one of the two premises is negative, according to Rule 4, the other premise must be positive, which means that one of the big events and small events has a positive connection with the middle term and the other has a negative connection with the middle term. Therefore, the connection between the part that has a positive connection with the middle term and the part that has a negative connection with the middle term must be qualitative and the conclusion must be negative. For example, all theists are not materialists; Some people are theists; Therefore, some people are not materialists. In this reasoning, the major premise is negative, so the conclusion is negative. Then, why is the conclusion negative and one of the premises must be negative? This is because, if the conclusion is negative, it must be because one of the large and small items in the premise is combined with the middle term, while the other item is excluded from the middle term. In this way, the premise of excluding the major item or minor item of the middle item is negative, so if the conclusion is negative, one of the prerequisites must be negative. On the other hand, if the conclusion is negative, it means that the inclusion relationship is denied. However, the positive premise reflects the fact that. No negative conclusion can be drawn from two positive premises. In other words, two positive premises can't get a negative conclusion. (2) if the conclusion is negative, then there must be a negative premise. Since the conclusion is negative, there is a negative connection between events, and this connection is established through the intermediary of the middle term, then one of these two terms must have a positive connection with the middle term. The other is negatively correlated with the mid-term. Therefore, one of the premises must be negative. No negative conclusion can be drawn from two positive premises. In other words, two positive premises cannot be negative. For example, some animals are mammals; Mammals are viviparous animals; So some viviparous animals are not mammals. This example violates this law and draws a negative conclusion from two positive premises, so it is incorrect reasoning. Rule 6: You cannot draw conclusions from two special premises. Rule 7: If one of the two premises is special, then the conclusion must be special. Ellipsis form of syllogism >; > The ellipsis form of syllogism is a syllogism that omits a premise or conclusion. For example, "you are a study Committee member and should be among the best." This is an omitted syllogism, omitting the major premise that "a member of the study Committee should be the best." Omitting syllogism can also omit minor premises or conclusions. Because a certain component of syllogism is omitted from the omitted syllogism, it is easy to hide all kinds of logical errors if it is not used properly. For example, someone said, "I'm not a translator, so I don't need to learn a foreign language well." This is an ellipsis syllogism that hides logical errors. When the omitted part is added, the error can be clearly seen. The complete form of this syllogism is: "anyone who is a translator needs to learn a foreign language well. I am not a translator, so I don't need to learn a foreign language well." This syllogism is obviously wrong. Because it violates the rule that "minor premise must be affirmative proposition", it also makes a logical mistake of "improper expansion of major items" in the conclusion. Sometimes it is necessary to supplement the omitted syllogism into a complete syllogism, and then see whether its premise is established and whether the reasoning process is effective. The effective test method is to supplement the omitted part and restore it to a complete syllogism. The supplementary process and procedure are: first, determine which proposition in the omitted syllogism is the conclusion. This can generally be determined according to the language symbol of the sentence expressing the proposition (the proposition after "because" is the premise and the proposition after "so" is the conclusion) or the contextual connection. Of course, if you still can't find a conclusion according to the above method, it is likely to omit the omitted syllogism in the conclusion part. Then, find the major premise or minor premise. Conclusion Once determined, according to the definition of syllogism structure, we can determine the concepts of subject, predicate, middle term and the composition of propositions as the premise of size. Thirdly, according to a certain syllogism format, we can reduce it to a complete syllogism. After doing these things, we can check whether these inferences are correct according to the rules of syllogism. & gt Example 1 All Hunan migrant workers in Beijing have applied for temporary residence permits; Those who have applied for temporary residence permits have obtained employment permits; Some migrant workers from Hunan came to Beijing as doormen; Some amateur martial arts school students have also become doormen; None of the students in amateur martial arts schools have obtained employment certificates. If all the above conclusions are true, then all except the following conclusions must be true? () A. Hunan migrant workers in Beijing have obtained employment certificates. B. None of the students in the amateur martial arts school have applied for a temporary residence permit. C. Migrant workers from Hunan to Beijing, some of whom are students from amateur martial arts schools. Some doormen do not have employment permits. The correct answer to this question is C, and syllogism is needed to solve this problem. From the first two sentences in the question, you can use syllogism to introduce option a. That is, "all Hunan migrant workers have obtained employment certificates." From the last sentence and stem of A, we can draw the conclusion that "all the students in amateur Wushu schools are not migrant workers from Hunan to Beijing". Therefore, it is impossible for migrant workers from Hunan to become students of amateur martial arts schools when they come to Beijing. That is, item C must be false. Option BD can be gradually introduced from the conditions given by the stem. Therefore, the correct answer is C. Annotations skillfully use syllogism rules for inference. Some economists are graduates of the department of mathematics in universities. Therefore, the graduates of some universities' mathematics departments are very good at enterprise management. Which of the following, if true, can guarantee the correctness of the above statement? () A. Some economists specialize in a certain field of economics. There is not much research on enterprise management. B. Some economists who are very good at business management are not graduates of the University Mathematics Department. C. People who are very good at business management are economists. D. All economists are very good at business management. The correct answer to this question is d, and the reasoning in this question can be regarded as omitting syllogism. To ensure that the reasoning is established, we must ensure that the minor premise of omission is true. Then, if we analyze the above figure, we will find that only by ensuring that all "economists" belong to "people who have studied enterprise management" can we ensure that some or some "college mathematics graduates" become "people who have studied enterprise management". The category of "people who study enterprise management" needs to include the category of "economists" in order to make the title stand. Comment on the omitted syllogism, supplement it appropriately when doing the problem, and learn to reason in the form of chart (Euler diagram). Of course, if you directly use the syllogism reasoning rules to push backwards, you can also get the answer quickly. For example, according to the minor premise and conclusion, we can know that the major premise is as follows: ① Affirm the proposition. Item (2) is an economist (because this concept does not appear in the conclusion); (3) the middle term in the major premise must be GAI (because the middle term in the minor premise is not GAI), so it can be concluded that the major premise must be D. Example 3 All smart people are nearsighted, and I am nearsighted, so I am smart. Which of the following accords with the logical structure of the above reasoning? () A. I am a fool, because smart people are nearsighted, and my eyesight is so good. All pigs have four legs, but this animal has eight legs, so it is not a pig. Xiao Chen is very happy, so Xiao Chen must be very fat. Because happy people get fat. D. All chickens have sharp mouths, and this bird that has been in the tree has a sharp mouth, so it is a chicken. The correct answer to this question is D. By analyzing the Euler diagram of the stem, it is found that only item D conforms to the syllogism reasoning structure of the stem. The "chicken" in this item is similar to the "smart man" in the stalk, and the "sharp mouth" is similar to "myopia". Therefore, their structures are similar. The answer should be item D. Comment on the problem of syllogism reasoning, which can be solved in the form of graph, that is, drawing according to the extended relationship of concepts and expressing it in the form of graph. If we judge according to the syllogism rules, we can see that the stem made the mistake that the middle item didn't get GAI, and so did the D item. Xiang Jun: Because Kornas is an excellent athlete, he is qualified to join the celebrity club. National wind: () First, some excellent athletes smoke. Two. Not all smokers are good role models for young people. Three. All the people accepted by celebrity clubs are good role models for young people. A.only ib.only ii c.only ii d.only ii and III analyze this problem. The correct answer is D, and the argument of national style includes two inferences. One is that "Cornus officinalis smokes" and "Cornus officinalis is not a good example for young people", and adding option 2 as a premise can form an effective syllogism. Another inference is from "cornus is not a good role model for young people" to "cornus should not be accepted by celebrity clubs", and adding option III as the antecedent here can form an effective syllogism. The argument of national style does not need to assume option I as the premise. Annotate the supplementary option to make it an effective syllogism.