6.1 Laws of logic. The law of contradiction (Formulation Imaginary contradictions Implicit contradictions Multiple contradiction problems)

4.1. Law of identity

The first and most important law of logic is the law of identity , which was formulated by Aristotle in his treatise Metaphysics as follows: “... to have more than one meaning means to have no meaning; if words have no (definite) meanings, then every opportunity to reason with each other, and in reality with oneself, is lost; for it is impossible to think anything if you do not think (every time) one thing ” ^[4] . One could add to these words of Aristotle a well-known statement that thinking (talking) about everything means not thinking (not talking) about anything.

The law of identity states that any thought (any reasoning) must necessarily be equal (identical) to itself, that is, it must be clear, precise, simple, definite. In other words, this law prohibits confusing and substituting concepts in reasoning (that is, using the same word in different meanings or putting the same meaning in different words), creating ambiguity, avoiding the topic, etc. For example , the meaning of the simple, at first glance, statements: “ The students listened to the teacher's explanation, ” is incomprehensible, because the law of identity is violated in it. After all, the word “ listened ”, which means that the whole statement can be understood in two ways: either the students listened attentively to the teacher, or they missed everything (and the first value is opposite to the second). It turns out that the statement was one, and he has two possible meanings, that is, the identity is violated: 1 ≠ 2. Similarly, the meaning of the phrase is not clear: “ Because of distraction in tournaments, the chess player repeatedly lost points .” Obviously, because of the violation of the law of identity, there are unclear statements (judgments).

The symbolic notation of this law is as follows: a → a (read: “If a, then a”), where a is any concept, statement, or whole reasoning. The formula: a → a , is identically true.

When the law of identity is broken involuntarily, out of ignorance, then simply logical errors occur; but when this law is violated deliberately, in order to confuse the interlocutor and prove to him some false thought, then there are not just errors, but sophisms. Thus, sophistry is an outwardly correct proof of false thought through deliberate violation of logical laws. Let us give an example of sophism: “ Which is better: eternal bliss or a sandwich? Of course, eternal bliss. And what could be better than everlasting bliss? Of course, nothing! But a sandwich is better than nothing, therefore it is better than everlasting bliss . ” Try to independently find the catch in this reasoning, determine where and how the law of identity is violated in it and expose this sophism. Here is another sophistry:

“We will ask our interlocutor:“ Do you agree with the fact that if you have lost something, then you don’t have it? "He replies:" I agree . " Let us ask him the second question: “ Do you agree with the fact that if you haven’t lost something, then do you have it? "-" I agree, "he answers. Now we will ask him the last and main question: “ Did you lose your horns today? What can he say? “ Not lost ,” he says. “ Consequently ,” we say triumphantly, “ you have them, because you yourself first admitted that if you didn’t lose something, then you have it.” Try to expose and this sophism, to determine where and how in this outwardly correct reasoning the law of identity is violated.

However, not only unclear judgments and sophisms are based on violations of the law of identity. By violating this law, you can create some kind of comic effect. For example, Nikolai Vasilyevich Gogol in the poem “Dead Souls”, describing the landowner Nozdryov, says that he was a “ historical person ”, because wherever he appeared, some kind of “ story ” happened to him. Many comic aphorisms are built on the violation of the law of identity. For example: " Do not stand anywhere, but something else will fall." Also with the help of violation of this law, many jokes are created. For example:

- I broke my arm in two places.

- Do not get to these places anymore.

Or such joke:

- Do you have quiet rooms in the hotel?

- We have all the rooms are quiet, except that the guests sometimes make noise.

As we see, in all the above examples the same technique is used: different meanings, situations, themes are mixed in the same words, one of which is not equal to the other, that is, the law of identity is violated.

Violation of this law also underlies many tasks and puzzles known to us since childhood. For example, we ask the interlocutor: “ For what (why) is water in a glass beaker? "- deliberately creating an ambiguity in this matter (why - for what and for what - for what subject, where ). The interlocutor answers one question, for example, he says: “ To drink, water the flowers ”, and we mean another question and, accordingly, another answer: “Behind the glass”.

We will offer our interlocutor the following task: “ How can we divide 12 in such a way as to make 7 without a trace?”. He will most likely solve it this way: 12: x = 7; x = 12: 7; x =? , and say that it does not dare - 12 can not be divided so that it turned out seven, and even without a residue. To this we will object to him that the task is completely solvable: we will depict the number 12 with Roman numerals: XII, and then we divide this record with one horizontal line: XII; As you can see, we got seven above (in Roman numerals) and seven below as well, and without a trace. It is clear that this task is sophistic and based on the violation of the law of identity, because its mathematical solution: 12: x = 7; x = 12: 7; x =? - not equal (not identical) to its graphic solution: XII.

The basis of all tricks is also a violation of the law of identity. The effect of any focus is that the magician does one thing , and the audience thinks something completely different , that is, what the magician does is not equal (not identical) to what the audience thinks, why it seems that the magician does something unusual and mysterious. When disclosing the focus, as a rule, we are perplexed and annoyed: it was so easy, how could we not notice it in time. For example, the famous illusionist Igor Emilievich Kio demonstrated such a focus. He invited a person from the hall (not a fake!) And, stretching for him an open notebook, offered to write anything there. At the same time, he did not see what the guest wrote in the book. Then Kio asked to tear out a page with what was written from the booklet, return the book to him, and burn the page in an ashtray.

After that, the magician, to everyone's surprise, read from the ashes what was written there. "How he does it? - the amazed spectators think. - Probably, there is some clever method of reading through the ashes or something else like that. ” In fact, everything is much simpler: in a magician's notebook through a page after the one on which the invitee makes his note, there is a carbon copy, and while he burns the torn page in the ashtray, the magician quickly and imperceptibly looks in his book that he wrote.

Here is another trick - intellectual. Think of a number (but not very large, so that it is not difficult to perform various mathematical operations with it). Now multiply this number by 2 and add 1 to the result. Now multiply what you got, by 5. Next, drop all the numbers from the resulting number except the last one and add 10 to this last digit, then divide the result by 3, add to the resulting number 2, then multiply the result by 6 and add 50. You got 92. As a rule, the interlocutor who is offered such a trick is surprised at how you know the result, because the number that he intended was unknown to you. In fact, the following happens. He conceived a certain number. For us, it's x . Then you ask him to multiply this number by 2. The result will be even.

Then you ask to add 1. The result will definitely be odd. Then you ask him to multiply this result by 5, and any odd number multiplied by 5 gives a new number, which will necessarily end with 5 (only not everyone remembers about it). Then you ask the interlocutor to discard all the digits from the resulting number except the last one and with it continue to perform various mathematical operations. Thus, all further operations are done with the number 5. The focus effect is that your interlocutor does not know that you know that this is 5, because it still seems to him that you do not know with what number the subsequent actions are performed. . So, the interlocutor thinks (or assumes) one thing, you do the other, and you cannot put an equal sign between the first and second, that is, the law of identity is violated.

Check yourself:

1. What does the law of identity say? Illustrate the effect of this law with an example. Which identically true formula is an expression of the law of identity?

2. What are sophisms? Come up with an example of some sophism and show how the law of identity is violated in it.

3. Determine how the law of identity is violated in the following sophisms:

1) 15 is one number; 15 is 7 and 8; but 7 and 8 are two different numbers, therefore, 15 are two different numbers.

2) All people have eyes, so all beings with eyes are humans.

3) One elderly person proves that his strength, despite his advanced years, did not diminish at all: “In my youth and youth I could not lift a barbell weighing 200 kg and now I can’t, therefore, my strength has remained the same”.

4) A girl was born in a Chinese family. When she was one year old, a neighbor came to her parents and began to woo the girl for her two-year-old son. The father said: - My girl is only one year old, and your boy is two, that is, he is twice her age, so when my daughter is 20 years old, your son will be 40. Why should I give my daughter my old groom? These words were heard by the wife and objected: - Now our daughter is a year old, and the boy is two, but in a year she will also be two and they will become the same age, so it’s quite possible in the future to give our girl as a neighbor boy.

4. How are violations of the law of identity used in the construction of comic aphorisms, some anecdotes, sophistic riddles and tasks? Give one example (with the exception of those discussed in the paragraph) of a comic aphorism, anecdote, riddle, or tasks in which the law of identity is violated, and show what its violations are.

5. Determine how the law of identity is violated in the following anecdotes:

1) - Do you know how to dive?

- I know how.

- How long are you under water?

- Until someone pulls out.

2) Doctor - patient:

- Every morning you need to drink warm water an hour before breakfast.

A week later:

- How are you feeling?

- Bad, doctor.

- Did you follow my instructions and drank warm water every morning an hour before breakfast?

- I tried my best to do it, but I could drink it for a maximum of fifteen minutes.

3) - Ah, these children's dreams. Has any of them come true?

- I have yes. As a child, when my mother brushed my hair, I dreamed that I did not have hair.

4) Teacher - student:

“Why are you late for school today?”

“I wanted to go fishing with my father in the morning, but he didn't take me with him.”

“I hope father explained to you why you should go to school and not go fishing?”

- Yes, he said that there are not enough worms and not enough for two.

5) Pedestrian - taxi driver:

- How much will you take to travel to the center?

- Two hundred rubles, sit down.

- Thank you, I asked only to find out how much I saved.

6. How is the law of identity broken in different foci? Give an example of some focus and show how the law of identity is violated in it.

4.2. Law of contradiction

The law of contradiction says that if one judgment asserts something, and another denies the same thing about the same object, at the same time and in the same relation, then they cannot be true at the same time. For example, two judgments: “ Socrates is high ”, “ Socrates is low ” (one of them asserts something, and the other denies the same thing, because high is not low, and vice versa) cannot be true at the same time when it comes to the same Socrates, at the same time of his life and in the same respect, that is, if Socrates in height is compared not with different people at the same time, but with one person. It is clear that when it comes to two different Socrates or one Socrates, but at different times in his life, for example, 10 years and 20 years, or the same Socrates and at the same time his life is considered in different ways for example, it is compared at the same time with high Plato and low Aristotle, then two opposite judgments can be true at the same time, and the law of contradiction is not violated. Symbolically, it is expressed by the following identically true formula: ¬ ( a ∧ ¬ a ), (read: “It is not true that a and not a”), where a is a statement.

In other words, the logical law of contradiction prohibits to assert anything and to deny the same thing at the same time. But is it really possible for someone to assert something and deny the same thing right there? Is it possible for someone to seriously prove, for example, that the same person is both tall and short at the same time and in the same respect, or that he is both fat and thin at the same time? and blond, and brunet, etc.? Of course not. If the principle of consistency in thinking is so simple and obvious, then is it worth calling it a logical law and in general paying attention to it?

The fact is that contradictions are contact , when the same is stated and immediately denied (the subsequent phrase denies the previous one in speech, or the subsequent sentence denies the previous one in the text) and distant ones , when there is a significant interval in speech or in the text. For example, at the beginning of his speech, a lecturer can put forward one idea, and at the end make a thought that contradicts it; likewise, in a book in one paragraph, it may be asserted that which is denied in another. It is clear that contact contradictions, being too noticeable, almost never occur in thought and speech. The situation is different with distant contradictions: being unobvious and not very noticeable, they often pass by the eyes or mind, are involuntarily skipped, and therefore they can often be found in the intellectual-speech practice. So, Vitaly Ivanovich Svintsov gives an example from one textbook in which, at intervals of several pages, it was first stated: "In the first period of creativity, Mayakovsky was no different from futurists," and then: "From the very beginning of his work, Mayakovsky possessed qualities that significantly distinguished him from representatives of futurism " ^[5] .

Contradictions are also obvious and implicit . In the first case, one thought directly contradicts the other, and in the second case, the contradiction follows from the context: it is not formulated, but implied. For example, in the textbook "Concepts of Modern Natural Science" (this subject is now being studied in all universities) from the chapter devoted to the theory of relativity by Albert Einstein, it follows that, according to modern scientific ideas, space, time and matter do not exist without each other: there is no one without other. And in the chapter on the origin of the Universe, it is said that it appeared about 20 billion years ago as a result of the Big Bang, during which matter was born that filled the whole space. From this statement it follows that space existed before the appearance of matter, although in the previous chapter it was said that space cannot exist without matter ^[6] . Explicit contradictions, as well as contact ones, are rare. Implicit contradictions, like distant ones, on the contrary, by virtue of their invisibility, are much more common in thinking and speech.

If we combine the divisions of the contradictions considered above into contact and distant, as well as explicit and implicit, we get four types of contradictions:

1. Contact and apparent contradictions (you can call them differently - explicit and contact, which does not change the essence).

2. Contact and implicit contradictions.

3. Distant and apparent contradictions.

4. Distant and implicit contradictions.

An example of a contact and apparent contradiction is the following statement: “ Driver N. grossly violated the rules when leaving the parking lot, since he did not take oral permission in writing.” Another example of contact and apparent contradiction: " A young girl of advanced years with a short hedgehog of dark curly hair with a graceful gait of a gymnast, limping, went to the scene." Such contradictions are so obvious that they can only be used to create some kind of comic effects. The remaining three groups of contradictions are comic in themselves, however, being unobvious and hardly noticeable, they are used quite seriously and create significant communicative interference. Therefore, our task is to be able to recognize and eliminate them. An example of contact and implicit contradiction: “ This manuscript made on paper was created in Ancient Russia in the 11th century. (in the XI century. in Russia there was no paper yet) ”.An example of a distant and apparent contradiction was cited above in the form of two statements about Vladimir Vladimirovich Mayakovsky from one textbook. An example of a distant and implicit contradiction is also considered above in the form of various statements about the relationship between matter and space from the textbook "Concepts of Modern Natural Science".

Finally, perhaps each of us is familiar with the situation when we tell our interlocutor, or he tells us: “You contradict yourself.” As a rule, in this case we are talking about distant or implicit contradictions, which, as we have seen, are quite often encountered in various spheres of thinking and life. Therefore, the simple and even primitive, at first glance, principle of consistency of thinking has the status of an important logical law.

Важно отметить, что противоречия также бывают мнимыми .

Некая мыслительная или речевая конструкция может быть построена так, что, на первый взгляд, выглядит противоречивой, хотя на самом деле никакого противоречия в себе не содержит. Например, известное высказывание Антона Павловича Чехова: « В детстве у меня не было детства », – кажется противоречивым, т. к. оно вроде бы подразумевает одновременную истинность двух суждений, одно из которых отрицает другое: « У меня было детство », « У меня не было детства».Thus, it can be assumed that the contradiction in this statement is not just present, but is the most blatant - contact and obvious. In fact, there is no contradiction in Chekhov’s phrase. Recall that the law of contradiction is violated only when it comes to the same subject, at the same time and in the same relation. In this statement, we are talking about two different subjects: the term " childhood » употребляется в различных значениях: детство как определённый возраст; детство как состояние души, пора счастья и безмятежности. Хотя и без этих комментариев, скорее всего, вполне понятно, что хотел сказать Антон Павлович Чехов. Обратим внимание на то, что кажущееся противоречие использовано им, по всей видимости, преднамеренно, для достижения большего художественного эффекта. И действительно, благодаря ненастоящему противоречию яркое и запоминающееся чеховское суждение стало удачным афоризмом. Таким образом, мнимое противоречие можно использовать как художественный приём. Достаточно вспомнить названия известных литературных произведений: «Живой труп» (Л. Н. Толстой), «Мещанин во дворянстве» (Ж. Мольер), «Барышня-крестьянка» (А. С. Пушкин), «Горячий снег» (Ю. В. Бондарев) и др. Иногда на мнимом противоречии строится заголовок газетной или журнальной статьи: «Знакомые незнакомцы», «Древняя новизна», «Необходимая случайность» и т. п.

Итак, закон противоречия запрещает одновременную истинность двух суждений, одно из которых нечто утверждает, а другое то же самое отрицает об одном и том же предмете, в одно и то же время и в одном и том же отношении. Однако этот закон не запрещает одновременную ложность двух таких суждений. Вспомним, суждения:

« Он высокий », « Он низкий », – не могут быть одновременно истинными, если речь идёт об одном и том же человеке, в одно и то же время его жизни и в одном и том же отношении (относительно какого-то одного образца для сравнения). Однако эти суждения вполне могут быть одновременно ложными при соблюдении всех вышеперечисленных условий. Если истинным будет суждение: « Он среднего роста », – тогда суждения: « Он высокий», «Он низкий », – придётся признать одновременно ложными. Точно так же одновременно ложными (но не одновременно истинными!) могут быть суждения:

«Эта вода горячая», «Эта вода холодная»; «Данная речка глубокая», «Данная речка мелкая»; «Эта комната светлая», «Эта комната тёмная» . Одновременную ложность двух суждений мы часто используем в повседневной жизни, когда, характеризуя кого-то или что-то, строим стереотипные обороты типа: «Они не молодые, но и не старые», «Это не полезно, но и не вредно», «Он не богат, однако и не беден», «Данная вещь стоит не дорого, но и не дёшево», «Этот поступок не является плохим, но в то же время его нельзя назвать хорошим» .

Check yourself:

1. О чём говорит закон противоречия? Объясните, почему этот закон не действует, если речь идёт о разных объектах, в разное время и в различном отношении. Проиллюстрируйте действие закона противоречия с помощью какого-нибудь самостоятельно подобранного примера. Какая тождественно-истинная формула является выражением закона противоречия?

2. Если логический принцип непротиворечивости мышления настолько прост и очевиден, то почему он возводится в ранг одного из основных законов логики?

3. Что такое контактные и дистантные противоречия? Придумайте по одному примеру контактных и дистантных противоречий.

4. Что такое явные и неявные противоречия? Придумайте по одному примеру явных и неявных противоречий. Почему дистантные и неявные противоречия встречаются в интеллектуально-речевой практике намного чаще, чем контактные и явные?

5. На какие четыре группы можно разделить все противоречия?

Найдите в художественной, публицистической, научной и учебной литературе по одному примеру для следующих видов противоречий: контактных и неявных, дистантных и явных, дистантных и неявных.

6. Что такое мнимые противоречия? Приведите два или три примера мнимых противоречий (за исключением тех, которые были рассмотрены в параграфе). Подумайте, почему мнимое противоречие часто используется в качестве художественного приёма?

7. В известной песне «Подмосковные вечера» есть такие слова:

«… речка движется и не движется… песня слышится и не слышится…». Реальное или мнимое противоречие представляет собой эта фраза? Justify your answer.

8. Все помнят знаменитые слова из сказки Александра Сергеевича Пушкина: « Кто на свете всех милее, всех румяней и белее? » Возможно, вы и раньше задумывались над тем, как можно быть румяней и белее одновременно. Реальное или мнимое противоречие присутствует в данном высказывании? Justify your answer.

9. Могут ли два суждения, одно из которых что-либо утверждает, а другое то же самое отрицает об одном и том же предмете, в одно и то же время и в одном и том же отношении, быть одновременно ложными? Если могут, то приведите несколько примеров таких суждений.

4.3. Закон исключённого третьего

Суждения бывают противоположными и противоречащими. Например, суждения: « Сократ высокий », « Сократ низкий », – являются противоположными, а суждения: « Сократ высокий », « Сократ невысокий », – противоречащими. В чём разница между противоположными и противоречащими суждениями? Нетрудно заметить, что противоположные суждения всегда предполагают некий третий, средний, промежуточный вариант. Для суждений: «Сократ высокий», «Сократ низкий» , – третьим вариантом будет суждение: «Сократ среднего роста». Противоречащие суждения, в отличие от противоположных, не допускают или автоматически исключают такой промежуточный вариант. Как бы мы ни пытались, мы не сможем найти никакого третьего варианта для суждений: «Сократ высокий», «Сократ невысокий» (ведь и низкий, и среднего роста - это всё невысокий).

Именно в силу наличия третьего варианта противоположные суждения могут быть одновременно ложными. Если суждение: «Сократ среднего роста» , – является истинным, то противоположные суждения: «Сократ высокий», «Сократ низкий» , – одновременно ложны.

Точно так же именно в силу отсутствия третьего варианта противоречащие суждения не могут быть одновременно ложными. Таково различие между противоположными и противоречащими суждениями. Сходство между ними заключается в том, что и противоположные суждения, и противоречащие не могут быть одновременно истинными, как того требует закон противоречия. Таким образом, этот закон распространяется и на противоположные суждения, и на противоречащие. Однако, как мы помним, закон противоречия запрещает одновременную истинность двух суждений, но не запрещает их одновременную ложность; а противоречащие суждения не могут быть одновременно ложными, т. е. закон противоречия является для них недостаточным и нуждается в каком-то дополнении. Поэтому для противоречащих суждений существует закон исключённого третьего , который говорит о том, что два противоречащих суждения об одном и том же предмете, в одно и то же время и в одном и том же отношении не могут быть одновременно истинными и не могут быть одновременно ложными (истинность одного из них обязательно означает ложность другого, и наоборот). Символическая запись закона исключённого третьего представляет собой следующую тождественно-истинную формулу: a

Check yourself:

1. В чём различие между противоположными и противоречащими суждениями? Почему противоположные суждения могут быть одновременно ложными, а противоречащие – не могут?

2. В чём сходство между противоположными и противоречащими суждениями? Почему закон противоречия является недостаточным для противоречащих суждений и нуждается в дополнении?

3. О чём говорит закон исключённого третьего? Какая тождественно-истинная формула является его выражением? В каком отношении находится закон исключённого третьего к закону противоречия?

4.4. Закон достаточного основания

Закон достаточного основания утверждает, что любая мысль (тезис) для того, чтобы иметь силу, обязательно должна быть доказана (обоснована) какими-либо аргументами (основаниями), причём эти аргументы должны быть достаточными для доказательства исходной мысли, т. е. она должна вытекать из них с необходимостью (тезис должен с необходимостью следовать из оснований).

Приведём несколько примеров. В рассуждении: «Это вещество является электропроводным (тезис), потому что оно – металл (основание)», – закон достаточного основания не нарушен, так как в данном случае из основания следует тезис (из того, что вещество металл, вытекает, что оно электропроводно). А в рассуждении:

«Сегодня взлётная полоса покрыта льдом (тезис), ведь самолёты сегодня не могут взлететь (основание)», – рассматриваемый закон нарушен, тезис не вытекает из основания (из того, что самолёты не могут взлететь, не вытекает, что взлётная полоса покрыта льдом, ведь самолёты могут не взлететь и по другой причине). Так же нарушается закон достаточного основания в ситуации, когда студент говорит преподавателю на экзамене: «Не ставьте мне двойку, спросите ещё (тезис) , я же прочитал весь учебник, может быть, и отвечу что-нибудь (основание)». В этом случае тезис не вытекает из основания (студент мог прочитать весь учебник, но из этого не следует, что он сможет что-то ответить, так как он мог забыть всё прочитанное или ничего в нём не понять и т. п.).

В рассуждении: «Преступление совершил Н. (тезис) , ведь он сам признался в этом и подписал все показания (основание)», – закон достаточного основания, конечно же, нарушен, потому что из того, что человек признался в совершении преступления, не вытекает, что он действительно его совершил. Признаться, как известно, можно в чём угодно под давлением различных обстоятельств (в чём только не признавались люди в застенках средневековой инквизиции и кабинетах репрессивных органов власти, в чём только не признаются на страницах бульварной прессы, в телевизионных ток-шоу и т. п.!).

Таким образом, на законе достаточного основания базируется важный юридический принцип презумпции невиновности , который предписывает считать человека невиновным, даже если он даёт показания против себя, до тех пор, пока его вина не будет достоверно доказана какими-либо фактами.

The law of sufficient reason, demanding evidence from any argument, warns us against hasty conclusions, allegations, cheap sensations, rumors, gossip and falsehood. Prohibiting to take anything only on faith, this law acts as a reliable barrier to any intellectual fraud. It is not by chance that he is one of the main principles of science (unlike pseudoscience or pseudoscience).

Check yourself:

1. What is the law of sufficient reason? Give three examples (with the exception of those discussed in paragraph) of violations of this law.

2. What is the legal principle of the presumption of innocence? How is it related to the law of sufficient reason?

3. What is the role of the law of sufficient reason in everyday thinking and everyday life? Answering this question, it is necessary to take into account that, sadly, it is natural for a person to lie. Quite often we utter an emotional phrase:

“What is the point of him (her, them) deceiving me?” Alas, sometimes there is a sense. And often a person lies not because of something or for something, but unconsciously, unaccountably. One of the varieties of such a lie is a situation where the interlocutor, telling some fiction about himself or simply embellishing reality, deceives not only and not so much us as much as himself, since at this time he is in the world of his own fantasies that are fictional and pleasant to him.

4. Highlight the original idea (thesis) and arguments (basis) in the reasoning below and determine whether the law of sufficient reason is violated in them:

1) These two straight lines are parallel, since they have no common points.

2) These two straight lines are parallel, since they lie in the same plane and have no common points.

3) This substance is a metal because it is electrically conductive.

4) My friend earns $ 10,000 a month, which cannot be doubted, because he himself confirms this.

5) A flying saucer was wrecked in one American state, because it was written about in newspapers, it was broadcast on the radio and even shown on television.

6) Today, ships cannot enter the bay because it is mined.

7) This person is not sick, because his temperature is not elevated.

8) This word should be written with a capital letter, because it stands at the beginning of the sentence.

5. Establish which of the basic laws of logic — identities, contradictions, excluded third, sufficient reason — is violated in the following examples:

1) - Why do you call this choir mixed? After all, there are only women here.

- Yes, but some are able to sing, while others are not.

2) When Michael Faraday turned to Humphry Davy with a request to take him to work in the laboratory, he asked for advice from one of the leaders of the Royal Institute. “Assign him,” was the answer, “to wash the labware. If he is capable of anything, he will definitely agree; if he does not agree, then he is not capable of anything. ”

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4) "A little artistic work." (M. M. Zoshchenko)

5) Wanting to know whether the air has weight, Aristotle inflated a bull bubble and weighed it. Then he let the air out of it and weighed again. The weight in both cases was the same. From this the philosopher concluded that air is weightless.

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8) A girl with full buckets - for good; empty buckets - to lose weight.

9) A student asks a teacher: “Is it possible to scold or punish a person for what he did not do?”

“No,” the teacher answers.

“In that case, do not scold or punish me,” says the student, “I haven’t done my homework today.”

10) - Give me one of your dogs.

- Which one?

- Black.

- Black is dearer to me than white!

- Then give me a white one.

- And white is dearer to me than both!

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12) So I came to you on Wednesday, But I will not come again; After all, I got into trouble In a very boring environment. And I can tell you boldly: All the guests “Wednesday has eaten!” (N. Wrangel)

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