Dialectical materialism holds that practice is the only criterion to test the truth of knowledge, which can be understood from the following three aspects:

(1) Whether a piece of knowledge is true or not cannot be answered by knowledge itself. To test whether a kind of knowledge correctly reflects objective things, we must go beyond the scope of knowledge and look for a standard to judge whether knowledge is consistent with objective things.

(2) The objective thing itself cannot answer whether knowledge correctly reflects it.

(3) Neither subjective knowledge nor objective things themselves can be used as the criteria for judging truth. Only by comparing and contrasting subjective and objective things can we test whether subjective understanding and objective things are consistent.

The only thing that can meet this requirement is the practice of the intersection of subjective and objective. Through practice, people can turn the ideas in their minds into reality. In this process, people compare the knowledge that guides their own practice with the results produced by practice to test whether the knowledge correctly reflects the objective things.

At this point, we can naturally draw a conclusion that practice is the only criterion to test the truth of knowledge. The famous sayings of Engels and Lenin quoted here in the textbook also illustrate this truth. ?

The textbook Related Links quotes Copernicus' solar system theory and demonstrates that practice is the only criterion to test the truth of knowledge. Today, we say that Copernicus's theory of the solar system is true, because it has been proved by Le Verrier's scientific experiments (one of the basic forms of practice).

This column re-emphasizes that practice is the only criterion to test the truth, and encourages us to study hard, test and confirm a series of scientific hypotheses in the future.