Man is the measure of all things

Man is the measure of all things, a famous philosophical proposition of the ancient Greek wise Protagoras in the 5th century BC. It was first seen in Plato's dialogue "Theaetetus": "Man is the measure of all things, the measure of the existence of existing things, and the measure of the non-existence of non-existent things." This means that the existence of things is relative to human beings. In terms of. Things are like how people feel; feelings about the same thing vary from person to person and from time to time. These different feelings are not true or false, right or wrong.

Before the 19th century, most thinkers regarded this proposition of Protagoras as a sophistry. It was not until GWF Hegel that from the perspective of the development of cognitive history, he affirmed that this proposition reflected the initiative of thinking. . This proposition represents the erroneous views of Protagoras' relativism and skepticism. It contains elements of subjective idealism, but it touches on the relationship between subjectivity and objectivity, indicating the progress of human understanding.

The most important philosophical saying passed down by Protagoras is what he said in "On Truth": "Man is the measure of all things. When he exists, everything exists, and when he does not exist, everything does not exist." He The people mentioned here refer to human feelings. What a thing is should be based on human feelings. To you, a thing is what it appears to your senses, and to me, it is how it appears to my senses.

When a gust of wind blows, if you feel cold, it is cold; if I feel hot, it is hot. The wind itself is neither hot nor cold. Similarly, whether a person's behavior is good or bad is also based on the person's feelings. If you think it is good, it is good; if I think it is bad, it is bad. Actions in themselves are neither good nor bad.

This philosophical saying of Protagoras had anti-traditional significance at the time. At that time, the traditional concept was that God was the measure of all things; the existence or non-existence of things, good or bad, were all determined by God. After Protagoras doubted the existence of God, he replaced God with others. This is undoubtedly of great significance in the history of Greek philosophy.

However, from our perspective today, this statement is incorrect, because the existence and nature of objective things do not change based on whether people feel them or how they feel. He regards the properties of things, such as hot and cold, as the product of subjective feelings and denies the objectivity of the properties of things. This makes it easy to fall into subjective idealism.