Basic laws of logic can be likened to the principles and rules that operate in nature. However, they have their own specifics, at least in that they operate not in the world around us, but in the plane of human thinking. But, on the other hand, the principles adopted in logic differ from legal norms in that they cannot be repealed. They are objective and act against our will. Of course, one can not argue according to these principles, but then hardly anyone will consider these conclusions reasonable.
Logical law is the pillar of science, both natural and human. If in everyday life one can still indulge in a stream of feelings that are incompatible with the rules for the construction and development of thought, one can allow logical gaps, then in serious works or discussions such an approach is unacceptable. For the foundation of any evidence base is the principles of correctjudgments.
What are these rules? Three of them were discovered in ancient times by Aristotle: these are the principle of consistency, the rule of identity and the law of the excluded middle. Centuries later, Leibniz discovered another principle - sufficient reason. All three laws of formal logic described by Aristotle are inextricably linked. If we allow for a moment that one link of the mindset is missing, then the others fall apart like a house of cards.
The law of the excluded middle can be summarized as follows: "Tertium non datur" or "There is no third." If we express two opposite maxims concerning the same subject (or a number of subjects, or a phenomenon), then one judgment will correspond to the truth, and the other will not. Between these statements, it is impossible to construct some third one that would reconcile the two main ones or serve as a connecting logical bridge between them. The simplest example of an excluded third is "This thing is white" and "This thing is not white." But it works only when both opposing maxims were expressed about the same thing, about a given time and about the same relationship.
The law of the excluded middle comes into force even when there is a contradictory or contradictory incompatibility between propositions A and B. The first is the statement of the opposite point of view. For example, the propositions "The Earth revolves around the Sun" and "The Sun revolves around the Earth" are counterarguments. A contradictory contradiction occurs when the phrase A states, and Bdenies anything: "Fire warms" and "Fire does not warm." Also, this contradiction occurs between particular and general judgments, when one is positive and the other is negative: “Some students already have diplomas” and “No student has a diploma.”
To thinking, especially scientific, special requirements are put forward: consistency, consistency of certainty. The Law of the Excluded Middle is the measure of the truth of our logical reasoning. For example, if we assert that “God is All-good”, then the maxim “God arranged eternal hellish torment for sinners” is meaningless. If we claim that God created a place of eternal torment for anyone, then we cannot claim that He is Good. Since God, as the object of our reasoning, cannot belong to contradictory signs, one of the two sentences above is true, while the second is false. The third is not given here.
