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Logics. Sophistry. Logical paradoxes (lecture notes)

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LECTURE No. 23. Sophisms. Logic paradoxes

1. Sophisms. Concept, examples

Revealing this issue, it must be said that any sophism is a mistake. In logic, there is also paralogisms. The difference between these two types of errors is that the first (sophism) was made intentionally, while the second (paralogism) was made by accident. The speech of many people abounds in paralogisms. Conclusions, even seemingly correctly constructed ones, are distorted in the end, forming a consequence that does not correspond to reality. Paralogisms, despite the fact that they are allowed unintentionally, are still often used for their own purposes. You can call this tailoring to the result. Without realizing that he is making a mistake, a person in this case derives a consequence that corresponds to his opinion and discards all other versions without considering them. The accepted consequence is considered true and is not verified in any way. Subsequent arguments are also distorted in order to better suit the thesis put forward. At the same time, as mentioned above, the person himself does not realize that he is making a logical mistake, he considers himself to be right (moreover, he is more savvy in logic).

Unlike a logical error that occurs involuntarily and is the result of a low logical culture, sophism is a deliberate violation of logical rules. It is usually carefully disguised as a true judgment.

Deliberately allowed, sophisms aim to win the argument at any cost. Sophism is designed to knock the opponent off his line of thinking, to confuse, to draw into the analysis of errors that do not relate to the subject under consideration. From this point of view, sophism acts as an unethical way (and at the same time obviously wrong) of conducting a discussion.

There are many sophisms created in antiquity and preserved to this day. The conclusion of most of them is curious. For example, the sophism "thief" looks like this: "The thief does not want to acquire anything bad; the acquisition of good is a good thing; therefore, the thief wants good." The following statement also sounds strange: "The medicine taken by the sick is good; the more good you do, the better; therefore, the medicine must be taken in large doses." There are other well-known sophisms, for example: "He who is sitting has risen; whoever has risen, he is standing; therefore, the one who is sitting is standing", "Socrates is a man; a man is not the same as Socrates; therefore, Socrates is something other than Socrates" , "These kittens are yours, the dog, their father is also yours, and their mother, the dog, is also yours. So, these kittens are your brothers and sisters, the dog and the bitch are your father and mother, and you yourself are a dog."

Such sophisms were often used to mislead the opponent. Without such a weapon in their hands as logic, the rivals of the sophists in the dispute had nothing to oppose, although they often understood the falsity of sophistical conclusions. Disputes in the ancient world often ended in fights.

With all the negative meaning of sophisms, they had a reverse and much more interesting side. So, it was sophisms that caused the emergence of the first rudiments of logic. Very often they pose the problem of proof in an implicit form. It was with sophisms that the comprehension and study of evidence and refutation began. Therefore, we can talk about the positive effect of sophisms, that is, that they directly contributed to the emergence of a special science of correct, demonstrative thinking.

A number of mathematical sophisms are also known. To obtain them, numerical values ​​are shuffled in such a way as to obtain one from two different numbers. For example, the statement that 2 x 2 = 5 is proven as follows: in turn, 4 is divided by 4, and 5 by 5. The result is (1:1) = (1:1). Therefore, four equals five. Thus, 2 x 2 = 5. This error is resolved quite easily - you just need to subtract one from the other, which will reveal the inequality of these two numerical values. A refutation is also possible by writing through a fraction.

As before, so now sophisms are used to deceive. The above examples are quite simple, it is easy to notice their falsity and do not have a high logical culture. However, there are veiled sophisms, disguised in such a way that it can be very problematic to distinguish them from true judgments. This makes them a convenient means of deception in the hands of logically savvy scammers.

Here are a few more examples of sophisms: “In order to see, there is no need to have eyes, since without the right eye we see, without the left we also see; apart from the right and left, we have no other eyes, therefore it is clear that the eyes are not necessary for sight" and "What you did not lose, you have; you did not lose your horns, so you have horns." The last sophism is one of the most famous and is often cited as an example.

We can say that sophisms are caused by insufficient self-criticism of the mind, when a person wants to understand knowledge that is still inaccessible, not amenable at a given level of development.

It also happens that sophism arises as a defensive reaction in the presence of a superior opponent, due to ignorance, ignorance, when the arguing does not show perseverance, not wanting to give up positions. It can be said that sophism interferes with the conduct of the dispute, but such a hindrance should not be classified as significant. With proper skill, sophism is easily refuted, although this leads to a departure from the topic of reasoning: one has to talk about the rules and principles of logic.

2. Paradox. Concept, examples

Turning to the question of paradoxes, one cannot fail to say about their relationship with sophisms. The fact is that sometimes there is no clear line by which you can understand what you have to deal with.

However, paradoxes are considered with a much more serious approach, while sophisms often play the role of a joke, nothing more. This is due to the nature of theory and science: if it contains paradoxes, then there is an imperfection in the underlying ideas.

What has been said may mean that the modern approach to sophistry does not cover the entire scope of the problem. Many paradoxes are interpreted as sophisms, although they do not lose their original properties.

paradox one can name an argument that proves not only the truth, but also the falsity of a certain judgment, i.e., proving both the judgment itself and its negation. In other words, paradox - these are two opposite, incompatible statements, for each of which there are seemingly convincing arguments.

One of the first and certainly exemplary paradoxes was recorded Eubulides - Greek poet and philosopher, Cretan. The paradox is called "The Liar". This paradox has come down to us in this form: "Epimenides claims that all Cretans are liars. If he tells the truth, then he lies. Is he lying or is he telling the truth?" This paradox is called "the king of logical paradoxes". To date, no one has been able to solve it. The essence of this paradox is that when a person says: "I am lying", he does not lie and does not tell the truth, but, more precisely, he does both at the same time. In other words, if we assume that a person is telling the truth, it turns out that he is actually lying, and if he is lying, then he told the truth about it before. Both contradictory facts are asserted here. Of course, according to the law of the excluded middle, this is impossible, but that is why this paradox has received such a high "title".

The inhabitants of the city of Elea, the Eleatics, made a great contribution to the development of the theory of space and time. They relied on the idea of ​​the impossibility of non-existence, which belongs Parmenides. Every thought according to this idea is a thought about what exists. At the same time, any movement was denied: the world space was considered integral, the world was one, without parts.

Ancient Greek philosopher Zeno of Elea known for compiling a series of paradoxes about infinity - the so-called paradoxes of Zeno.

Zeno, a student of Parmenides, developed these ideas, for which he was named Aristotle "ancestor of dialectics". Dialectics was understood as the art of reaching the truth in a dispute, revealing contradictions in the opponent's judgment and destroying them.

The following are the direct aporias of Zeno.

"Achilles and the tortoise" represents an aporia about movement. As you know, Achilles is an ancient Greek hero. He had remarkable abilities in sports. The turtle is a very slow animal. However, in an aporia, Achilles loses the race to the tortoise. Suppose Achilles needs to run a distance of 1, and he runs twice as fast as a turtle, the last one needs to run 1/2. Their movement starts at the same time. It turns out that after running the distance 1/2, Achilles will find that the tortoise has managed to overcome the segment in the same time 1/4. No matter how much Achilles tries to overtake the tortoise, it will be ahead exactly by 1/2. Therefore, Achilles is not destined to catch up with the tortoise, this movement is eternal, it cannot be completed.

The inability to complete this sequence is that it is missing the last element. Each time, having indicated the next member of the sequence, we can continue by indicating the next one.

The paradox here lies in the fact that the endless sequence of successive events must actually come to an end, even if we could not imagine this end.

Another aporia is called "dichotomy". The reasoning is based on the same principles as the previous one. In order to go all the way, you need to go halfway. In this case, half the path becomes a path, and in order to pass it, it is necessary to measure half (that is, already half of the half). This continues ad infinitum.

Here the order of succession is reversed compared to the previous aporia, i.e. (1/2)n..., (1/2)3, (1/2)2, (1/2)one. The series here does not have the first point, while the aporia "Achilles and the tortoise" did not have the last.

From this aporia, it is concluded that the movement cannot begin. Proceeding from the considered aporias, the movement cannot end and cannot begin. So it doesn't exist.

Refutation of the aporia "Achilles and the Tortoise".

As in the aporia, Achilles appears in its refutation, but not one, but two turtles. One of them is closer than the other. The movement also starts at the same time. Achilles runs last. During the time that Achilles runs the distance separating them at the beginning, the nearest tortoise will have time to crawl a little ahead, which will continue indefinitely. Achilles will get closer and closer to the tortoise, but he will never be able to overtake it. Despite the obvious falsity, there is no logical refutation of such an assertion. However, if Achilles begins to catch up with a distant tortoise, not paying attention to the near one, he, according to the same aporia, will be able to come close to it. And if so, then he will overtake the nearest turtle.

This leads to a logical contradiction.

In order to refute the refutation, i.e., to defend the aporia, which is strange in itself, it is proposed to throw away the burden of figurative representations. And to reveal the formal essence of the matter. Here it should be said that the aporia itself is based on figurative representations and to reject them means to refute it as well. And the rebuttal is quite formal. The fact that two turtles are taken instead of one in the refutation does not make it more figurative than an aporia. In general, it is difficult to talk about concepts that are not based on figurative representations. Even such philosophical concepts of the highest abstraction as being, consciousness, and others are understood only thanks to the images that correspond to them. Without the image behind the word, the latter would remain only a set of symbols and sounds.

Stages implies the existence of indivisible segments in space and the movement of objects in it. This aporia builds on the previous ones. Take one immovable row of objects and two moving towards each other. Moreover, each moving row in relation to the immovable one passes only one segment per unit of time. However, in relation to the moving - two. which is considered contradictory. It is also said that in an intermediate position (when one row has already moved, as it were, the other has not) there is no room for a fixed row. The intermediate position comes from the fact that the segments are indivisible and the movement, even though it started simultaneously, must go through an intermediate stage when the first value of one moving series coincides with the second value of the second (movement, provided that the segments are indivisible, is devoid of smoothness). The state of rest is when the second values ​​of all rows coincide. The fixed row, if we assume the simultaneity of the movement of the rows, must be in an intermediate position between the moving rows, and this is impossible, since the segments are indivisible.

Notes

1. Makovelsky A. O. History of Logic. M., 1967.

2. V. S. Meskov, Essays on the Logic of Quantum Mechanics. M., 1986.

3. Demidov I. V. Logic: Textbook / Ed. B. I. Kaverina. 2nd ed. M.: Exam, 2006.

4. V. I. Kirillov and A. A. Starchenko, Logic. M., 2001.

5. Ibid.

6. Soviet Encyclopedic Dictionary / Ed. A. M. Prokhorova. 4th ed., rev. and additional M.: Sov. encycl., 1990.

7. Soviet Encyclopedic Dictionary / Ed. A. M. Prokhorova. 4th ed., rev. and additional M.: Sov. encycl., 1990.

8. Savchenko N. A. Course of lectures. Logics. M., 2002.

9. Savchenko N. A. Course of lectures. Logics. M., 2002.

10. Ibid.

11. Savchenko N. A. Course of lectures. Logics. Topic 4. M., 2002.

12. Savchenko N. A. Course of lectures. Logics. M., 2002.

13. Eryshev A. A. Logic. M., 2004.

14. Ibid.

15. Eryshev A. A. et al. Logic. M., 2004.

16. Savchenko N. A. Course of lectures. Logics. M., 2002.

17. Savchenko N. A. Course of lectures. Logics. M., 2002.

18. Povarnin S. I. Art of dispute: on the theory and practice of dispute. General information about the dispute. About proofs, questions of philosophy. N. 1990.

19. Ibid.

20. Ivin A. A. Logic: Textbook. M.: Gardariki, 2000.

21. Povarnin S. I. Art of dispute: on the theory and practice of dispute. General information about the dispute. About proofs, questions of philosophy. N. 1990.

Author: Shadrin D.A.

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