What are the four basic laws of logic?

Identity, law of contradiction, law of excluded middle and full rationality in logic.

I. Identity: In the same thinking process, each thought should maintain its own identity.

Identities can be expressed as "A is A" or "p→p". Where a stands for any concept and p stands for any judgment. "A is A" or "p→p" means that each concept or judgment keeps its identity in the same thinking process. The main idea of identity is to maintain ideological certainty.

The requirement of identity for thinking form includes two aspects: first, the concept should be clear, and second, the judgment should be consistent.

Second, the law of contradiction: in the same thinking process, two mutually negative ideas cannot be true, and one must be false.

The law of contradiction can be expressed as "A is not human" or "pA-P". The main purpose of the law of contradiction is to keep the consistency of thought.

The requirement of the law of contradiction to the form of thinking includes two aspects: one is that concepts should be compatible, and the other is that judgments should be consistent.

Third, law of excluded middle: In the same thinking process, two mutually negative thoughts cannot both be false, but there must be a truth.

Law of excluded middle can be expressed as "A or Not A" or "PV → p". Law of excluded middle's main idea is to keep the clarity of thinking.

Law of excluded middle's requirements for thinking form include two aspects: first, the concept should be clear, and second, the judgment should be clear.

Fourth, the law of sufficient reason: this law is usually expressed as: any judgment must have (sufficient) reasons. That is, if anything is true or true; If any statement is true, there must be a good reason why it is this way and not that way.

The formulation of the rule of sufficient reason originated from the German philosopher Leibniz, G.W.,1at the end of July and1at the beginning of August. However, Leibniz himself did not regard the principle of sufficient reason as a logical law.

Extended data:

The basic laws of traditional logic

The basic law of traditional logic is also called the basic law of thinking or the law of thinking. Including identity, law of contradiction and law of excluded middle. Some logicians also include the law of sufficient reason.

They are the basis of special laws or rules of various thinking forms.

The law of contradiction and law of excluded middle were first put forward by Aristotle, an ancient Greek philosopher and logician. Aristotle did not explicitly put forward the idea of identity, but in some of his remarks, he already had the idea of identity.

Traditional logicians believe that the basic laws of thinking, such as uniformity, law of contradiction and law of excluded middle, embody the main feature of correct thinking-certainty from different aspects.

The certainty of thinking is the reflection of the relative certainty of objective things and the objective basis of fundamental laws of traditional logic. Idealists deny the objectivity of these laws of thinking. They either think that these laws are inherent transcendental categories of thinking itself, or think that the laws of thinking are rules established by people according to agreements.

The basic laws of traditional logic have a normative effect on people's thinking. If you don't follow the requirements of these laws, there will be ideological confusion and mistakes.

Baidu encyclopedia-homology

Baidu Encyclopedia-Law of Contradiction

Baidu Encyclopedia-law of excluded middle

Baidu encyclopedia-sufficient reason method

Baidu Encyclopedia-Basic Laws of Traditional Logic