4 explain the main logic of the law on the simple examples

We often hear phrases like "it is illogical" and "where is the logic here." Intuitively, the logic - it is something about our discussion, conclusions, the structure of thought. In general, it is. Logic - the science that appeared in the V century BC and studies the laws and forms of thought.

Under the form of thinking to understand the structure of thought, not its content. For example, in terms of the logic of the expression "All shmumriki hzhuyut tofts with shtetselloy on faflak. Finkus - shmumrik. Finkus hzhuet tofts with shtetselloy on faflak "is absolutely true, and" All the planets of the solar system revolve around the sun. The earth revolves around the sun. Consequently, the Earth - the planet of the Solar System "- no.

All logic "lives" on the four laws. We will understand what these laws are and how they work.

1. law of identity

Every thought must be equal to itself, should not have more than one value.

What is the essence

Before our era Aristotle said: "... To have more than one meaning - it means not to have any value; if words have no (certain) values, then lost all opportunity to talk with each other, and reality and with himself, for it is impossible to think anything, if you do not think every time something one. "

examples of violations

The most popular example of violation of the law of identity - the phrase "the students listened to a lecture." The word "listened to" can be understood in two ways: either the students listened to the teacher carefully whether all missed.

An example of a violation of the law of identity, and this is a joke:

- I broke my arm in two places.

- Do not go to these places.

As a result, a bit more complex disorders of the identity of the law obtained sophistry. Sophistry - it looks correct proof of a false idea with the help of an intentional violation of the laws of logic.

Is it better to eternal bliss or a sandwich? Of course, the eternal bliss. And what could be better than eternal bliss? Of course, nothing! But the sandwich because it is better than nothing, so the sandwich better of eternal bliss.

The catch here is that the word "nothing" used the first to mean "any object or phenomenon", and then in the sense of "lack of something"

How to apply in life

The first law of logic will recognize sophistry. The first thing you should pay attention - ambiguous words.

2. the law of contradiction

Statement and its negation can not both be true.

What is the essence

If one judgment says something and the other denies the same thing about the same subject in the same time and in the same respect, they can not both be true.

For example, two judgments - "black cat" and "cat white" - can not both be true if we are talking about one and the same Kotik, At the same time and in the same respect. That is, the color of a cat compared to the same palette.

examples of violations

"This red cat left on the carpet around the black hairs." And from childhood - "Shut your mouth and eat."

How to apply in life

The hardest part - to reveal a contradiction. The phrase "as a child I had no childhood" does not violate the law of contradiction, and "made an oral report in writing" breaks. So, the main thing - to understand, there is a contradiction or a play on words.

3. The law of the excluded middle

Two contradictory statements about the same subject at the same time and in the same respect can not be simultaneously true and can not both be false

What is the essence

Judgments are opposite and contradictory.

Opposing judgment always assume a third, intermediate option. For example, for the judgment "big house" and "small house"Intermediate is" a house of average size. " For contrary to the judgment, there is no third option. For example, for the judgment "big house" and the "small house" the third the best one is not supposed to be.

Thus, two contradictory statements about the same subject, in the same time and in the same respect can not be simultaneously true and can not both be false.

example disorders

Judgment "old cat" and "cat youngish" about the same seals in one and the same time can not be true simultaneously.

How to apply in life

Examples of simple to outrageous, but in the life of the law of contradiction is violated more so: between conflicting judgments have more of the monologue, and do judgment can be expressed not so clearly. How is it to be? Carefully listen to what he says interlocutorAnd follow the thought. If all other laws are not violated, look again to the wording. Perhaps there disguised contradictory judgments.

4. The law of sufficient reason

Any idea (thesis) in order to be valid must necessarily be proved by any arguments, and these arguments should be sufficient grounds for the original idea, that is, it must follow from them.

What is the essence

Remember what the presumption of innocence? It is based on the law of sufficient reason. The principle of the presumption of innocence requires to consider a man innocent, even if he gives evidence against himself, as long as his guilt has not been reliably proven by any facts. In other words, the confession does not guarantee that the person really committed the crime, but the clues and evidence - may. That is an admission of guilt - the lack of foundation, and the facts and evidence pointing to criminal - sufficient.

example disorders

"Do not put me a deuce. I read the entire book and may have something to tell you. " The conclusion does not follow from the base: a student can read the entire textbook, but it does not follow that it will be able to say something.

How to apply in life

law of sufficient reason warns against hasty conclusions. If we remember that any claim must be supported by the facts, it will help to recognize the cheap sensationalism and stories.