Lecture
The subject of logic — the forms, laws, and operations of thought, compliance with which is a necessary condition for cognizing the surrounding world.
In logic, four fundamental laws can be distinguished, which express the fundamental properties of logical thinking – its definiteness, non-contradiction, consistency, and validity. These laws include: the law of identity, non-contradiction, excluded middle, and sufficient reason.
1) The law of identity. Any thought in the process of reasoning must have a definite, stable content. This fundamental property of thought – its definiteness – is expressed by the law of identity: any thought in the process of reasoning must be identical to itself (A is A, or A = A, where A is any thought). One must not identify different thoughts, nor treat identical thoughts as non-identical. Violation of this requirement in the process of reasoning is often connected with the different verbal expression of one and the same thought. On the other hand, the use of ambiguous (polysemous) words can lead to the mistaken identification of different thoughts. The identification of different thoughts is often linked to differences in profession, education, etc. The identification of different concepts constitutes a logical error – the substitution of concepts, which may be either unconscious or deliberate.
2) The law of non-contradiction. Logical thinking is characterized by consistency (non-contradiction). Contradictions destroy thought and hinder the process of cognition. The requirement of consistency of thought is expressed by the formal-logical law of non-contradiction: two mutually incompatible judgments cannot both be true at the same time; at least one of them must necessarily be false. This law is formulated as follows: it is not the case that both A and not-A (two thoughts, one of which negates the other, cannot both be true). The law of non-contradiction applies to all incompatible judgments.
3) The law of excluded middle. This law applies only to contradictory (contradictorial) judgments. It is formulated as follows: two contradictory judgments cannot both be false at the same time; one of them must necessarily be true: A is either B or not-B. Either the assertion of a given fact is true, or its negation is. Contradictory judgments are judgments in one of which something is asserted (or denied) about every object of a certain set, while in the other it is denied (asserted) about some part of that set. These judgments cannot be simultaneously either true or false: if one of them is true, the other is false, and vice versa. Also contradictory are two judgments about the same object, in one of which something is asserted while in the other the same thing is denied.
4) The law of sufficient reason. This law expresses the requirement that a thought be proven and grounded: any thought is recognized as true if it has a sufficient reason. If there is B, then there is also its reason A. A person's personal experience can serve as a sufficient reason for thoughts. The truth of some judgments is confirmed by directly comparing them with the facts of reality. The truth of laws and axioms has been confirmed by the practice of humankind and therefore does not need new confirmation. To confirm some particular case, there is no need to justify it by means of personal experience. The sufficient reason for a given thought can be any other, already verified and established thought, from which the truth of the given one necessarily follows.
1. What does the word “logos” mean?
A) The human word in general. B) A universal law, the foundation of the world.
C) Law, thought, word, meaning. D) Conversation, judgment.
2. What is the subject of study of logic?
A) Abstract thinking. B) Figurative (imaginative) thinking.
C) Laws, forms and methods of thought. D) Linguistic texts.
3. What is thinking?
A) It is the purposeful, mediated and generalized reproduction of the connections and relations of an object.
B) It is the holistic reproduction of an object directly
affecting the sense organs.
C) It is a sensory image of a previously perceived object.
D) It is a subjective image of the objective world.
4. Name the basic forms of abstract thought.
A) Concept, judgment and inference.
B) Laws, forms and methods of thought.
C) Analysis, synthesis, generalization.
D) Question, hypothesis and theory.
5. Who is the founder of inductive logic?
A) Aristotle. B) F. Bacon. C) G. Hegel. D) G. Leibniz.
6. What kind of logic did G. Leibniz found?
A) Deductive. B) Inductive.
C) Traductive. D) Symbolic.
7. When was mathematical logic formed?
A) In the 5th century BC. B) At the beginning of the 18th century.
C) In the second half of the 19th century. D) At the beginning of the 20th century.
of thought?
A) The law of identity. B) The law of non-contradiction.
C) The law of excluded middle. D) The law of sufficient reason.
9. Which logical laws were formulated by Aristotle?
A) The law of identity. B) The law of non-contradiction.
C) The law of excluded middle. D) The law of sufficient reason.
10. Which logical law was formulated by G.W. Leibniz?
A) The law of identity. B) The law of non-contradiction.
C) The law of excluded middle. D) The law of sufficient reason.
11. Which logical law's requirement is violated in the following statement:«Two corpses were found: one dead, and the other still alive»?
A) The requirement of the law of excluded middle is violated.
B) The requirement of the law of identity is violated.
C) The requirement of the law of non-contradiction is violated.
D) The requirement of the law of sufficient reason is violated.
12. Which logical law is violated in the announcement: «Dear residents! On Wednesday, August 20, pest control treatment against cockroaches will be carried out in your building. We kindly ask residents to be at home at this time, since the extermination of the cockroaches will be carried out together with them».
A) The law of identity. B) The law of non-contradiction.
C) The law of excluded middle. D) The law of sufficient reason.
13. Which logical law does the speaker violate:«Whoever wears a «Adidas» hat will sell out our Motherland»?
A) The law of identity. B) The law of non-contradiction.
C) The law of excluded middle. D) The law of sufficient reason.
14. Which logical law is violated in the following statement:«Perpetual motion machine. Warranty: 48 days»?
A) The law of identity. B) The law of non-contradiction.
C) The law of excluded middle. D) The law of sufficient reason.
15. The requirements of which logical law are fulfilled in Lermontov's text:«If you don't kill me, I will stab you at night from around the corner. There is no room for the two of us on this earth»?
A) The law of identity. B) The law of non-contradiction.
C) The law of excluded middle. D) The law of sufficient reason
incorrect?
A) The city of Tyumen is a singular, concrete and positive concept.
B) Student is a general, concrete and positive concept.
C) Dinner set is a general, concrete and positive concept.
D) A student group that has not prepared for classes is a singular, abstract and negative concept.
5. What relation holds between the concepts “student” and “drug addict”?
A) Identical. B) Overlapping.
C) Subordinate. D) Coordinate.
6. What relation holds between the concepts “criminal code” and “civil code”?
A) Coordinate. B) Contradictory.
C) Overlapping. D) Contrary.
7. What relation holds between the concepts «rich» and «poor»?
A) Coordinate. B) Contradictory.
C) Overlapping. D) Contrary.
8. In which case is the type of relation between the concepts defined incorrectly?
A) Frenchman and artist – overlapping.
B) Ground squirrel and rodent – subordination.
C) Theft and robbery – coordination.
D) Beautiful and ugly – contrariety.
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