The four classical laws of logic are the foundation of human thinking. They are based on the natural features of the world. These principles are unshakable - they cannot be violated or circumvented.
Origin of laws
According to the scientific definition, logical laws are the laws on which human thinking is built. They appeared as a generalization of the vast experience of the interaction of people with the surrounding reality. The reality that a person comes into contact with every day is reflected in his consciousness. It is this process that is considered to be thinking. It happens not chaotically and randomly, but according to certain laws.
These rules are identified and formulated by logic. As a science, this discipline explains the principle of human inferences. Laws are repeating stable bonds that affect the functioning, structure and development of thoughts. They are determined by the objective features of the outside world. That is why people can not change them at their discretion, offering their own logical laws. This property of them makes it possible to clearly define and formulate the basic principles according to which thinking works.
Basis of thinking
All logical laws are an immutable axiom, a truth that does not need proof. They remain the most important part of the cognitive process and scientific reasoning. Thanks to these norms, it is possible to determine the truth and falsity of thoughts.
At the same time, logical laws are features that are characteristic only for its narrow scope. That is, they are far from absolute, they can only be used in the thought process. But these axioms should not be transferred to the outside world.
Types of laws
The laws of logic have a classification. The first group includes those norms that are associated with abstract thinking - judgments, concepts and conclusions. The second type is associated with laws of a universal universal nature. They are also called basic. In particular, this is the law of identity in logic, contradiction, excluded third and sufficient grounds.
Why are they considered essential? Because they work the same way in any thought process, are used in evidence and conclusions, and finally have the properties of correct thinking: logical consistency, validity, consistency and certainty.
Discovery story
The first three laws are the so-called logical laws of Aristotle, formulated by the ancient Greek philosopher in the 4th century BC. e. They became the basis for all subsequent development of scientific thought. In the XVIII century, Gottfried Leibniz discovered another law - the law of sufficient reason.
In the future, many scientists tried to question these norms. Thus, mathematical and symbolic logic appeared, while the 4 laws described above are relevant only for traditional logic.
Identity
According to the classical classification, the law of identity is considered the most important. In logic, he is paramount. This principle consists in the fact that correct and true thought must remain definite and maintain its own uniqueness throughout the entire argument until the final conclusion. Without this law, human thinking would lose its main tool. Acting within its framework, people reason according to the principles laid down by nature in the world around us.
Logic as a science comes from the following rule. All qualities of items must be defined. This property of them helps human thinking to isolate and distinguish the objects of their thinking from the surrounding reality. Without it, one cannot reason using concepts. The stable and the general are fixed in them - that which reveals the essence of identity.
Substitution of concepts
Well-known formal logical laws cannot be violated, because in this case a person will reason in a contradictory and unnatural way. Failure to comply with the principle of identity leads to typical thinking errors. First of all, this is a substitution of concepts. Juggling thoughts and giving one after another, you can break the chain of reasoning. In addition, this threatens communication complications with the interlocutor.
This rule is especially important in scientific controversy, where each concept has its own strict and defined framework. Such disputes do not allow ambiguity. Also in ordinary communication, people can misunderstand each other only because they use concepts in different meanings. This error is often associated with the use of homonyms. They may coincide in shape, but have different meanings (for example, “gender” is both a gender and a cover under your feet).
Contradiction
According to the theory, the law of contradiction lies in the fact that two opposing statements cannot simultaneously correspond to the truth. This principle is of great importance for the entire thought process. It is also important that the law of contradiction expresses the objective properties of things around. Its violation leads to a paradox. If it is not observed, things would lose their properties, cease to be themselves.
Humanity has long discovered this feature and just as long ago learned to use it in its own reasoning. If objects cannot simultaneously have and do not have their own properties, it means that people do not have the right to make their own judgments, ignoring the principle of contradiction. It is important to note that this law applies only to mutually exclusive phenomena. In other words, one cannot simultaneously say about a person that he is hardworking and lazy.
If you violate the law of contradiction, you can go to demagogy and prove any false statement. This liberty moves thought away from objective reality, leads it into the jungle of fabrications and assumptions. For many centuries, science has been developing only because it exists within the framework of the law of contradiction. If a person leaves these limits, his thinking runs the risk of becoming incoherent, unsystematic and chaotic. Such reasoning is not tied to anything; they are contrary to formal logic.
The principle of contradiction implies that one of the opposite judgments is false, but does not indicate which one is false and which is true. At the same time, it is necessary to use this law, realizing where the limits of its action end. For example, there will be no contradiction when it comes to the same phenomena with different relationships. The following situation can be used to illustrate this reservation. Andrey is a swimming champion and at the same time is not a boxing champion. Although we are talking about one title, there is no contradiction here, since it can relate to a variety of sports disciplines.
Excluded Third
According to this law, two conflicting theses cannot be false or true at the same time - one of them is false, the other is true. There should not be a third. This law largely echoes the principle of contradiction. It reflects the sequence of human thinking. This law does not allow confusion. If the opposite is true, then the other is false (and vice versa).
At the same time, the law of the excluded third does not characterize the phenomenon. Checking which one is true can only be done in practice. To do this, it is necessary to establish the conformity or inconsistency of the statement of reality. The main meaning of this law is that the principle indicates the direction for the search for truth. He emphasizes - the solution lies in the opposite "yes" or "no." The law denies the possibility of a median response.
Uncertainty of Phenomena
The law of the excluded third requires a person to clarify the concepts. This is necessary in order to find answers to an alternative question. At the same time, this law cannot be absolutized. It does not reflect the transitional qualities of phenomena and therefore is not universal. For example, this principle does not apply when it comes to the clinical death of a person, an unproven hypothesis, long-term weather forecast.
The fact is that in the situations described above, thinking goes beyond the limits of classical two-valued logic. Uncertainty is added to truth and falsehood - something in between containing signs of both. In addition, it is necessary to consider another feature of surrounding things and phenomena. All of them can be internally contradictory and include opposing features. The law of the excluded third does not consider the features of the objective world. It is much more used in theoretical disciplines, for example, in economics and jurisprudence.
Good reason
The last law of thinking is the law of sufficient reason. It is based on the most important principle - every true thought must have a solid foundation. As evidence of the correctness of the argument, facts, laws, rules, regulations, and other arguments that were previously recognized as truthful can be used. In order to remain consistent in his speech, a person must build his conclusions only on a sufficient basis.
This principle exists due to the close relationship of objects and phenomena existing in the world. Thanks to her, a person, knowing one fact, can deduce one more. For example, the official language of Brazil is Portuguese, which suggests that in former times this country was a Portuguese colony.
Causality
All logical laws and rules have well-known examples. The principle of sufficient foundation was often used by Conan Doyle in his books about Sherlock Holmes. The fictional detective, conducting his investigations, often turned to causal relationships. Each of his conclusions corresponded to the worked out scheme. Holmes reconstructed the cause by building a chain from a logical basis (that is, a real consequence) to a logical consequence (that is, a real cause).
Doctors use a similar method. They, like no one, know and understand the logical laws. Examples of their use can be found in the diagnosis of patients. Finding out the circumstances of the disease, doctors build a relationship between the effect and the cause. Moreover, their findings are checked with extra care. To do this, experts resort to convincing arguments, confirmed by science and practice.
The law of sufficient reason requires the abandonment of unfounded conclusions. He does not allow vague evidence of the truth of human thought. This law is a convenient tool in the right hands. With its help, you can separate the false from the true and come to the right conclusion. Another feature of this law is its abstract nature, which is based on the relative stability and mutual conditionality of phenomena and objects.