Zhang Dongsun said, "Materialist dialectics is a far-fetched and confusing thing and completely wrong." He also said that the positive, negative and unity of dialectics are completely useless in science. "The scientific method, since ancient times, is still only the so-called method of observation, induction, measurement, assay, statistics, etc., and has never used dialectics." [2]
Dialectical logic does not conform to the law of identity, the law of exclusion of middle and the law of non-contradiction. If these three rules are universally applicable, then dialectical logic has no place to be ashamed. All theories are tools of man, and man needs all kinds of tools, as long as they are useful and can bring benefits. Formal logic is not only useful, but allows the natural sciences to flourish. So formal logic is a very useful tool, and a great tool. But just formal logic is great does not mean that all logical relations must conform to formal logic. What is more, we should not blindly deny dialectical logic.
Guan Min also said that in traditional Chinese culture, attention is paid to dialectical thinking, and the thinking habit of formal logic is lacking, so it is decadent and backward. [2] It is unreasonable for Guan Min to attribute China's backwardness entirely to dialectical logic. After the Renaissance, Western science advanced rapidly, and China fell further and further behind. This is a fact, but this does not mean that dialectical logic must lead to backwardness and decay, and the fact that China's 5,000 years of glorious civilization can not be denied. Hegel and the ancient Greek philosophers also studied dialectical logic and did not slow down the development of Western civilization.
4.3 Blind negation of formal logic
At the other extreme is the blind negation of formal logic. Hegel mocked formal logic, "The law of identity is then expressed as 'everything is identical with itself '; Or 'A is A', negative: 'A cannot be both A and non-A at the same time.' Such propositions are not really laws of thought, but only laws of abstract intelligence. The form of this proposition is itself in contradiction. For a proposition must make the distinction between subject and predicate, but this proposition does not do what its form requires of it." "It would be ridiculous if people were to speak according to this law which pretends to be the truth." "Do not think of identity simply as abstract identity, as identity that excludes all differences. This is what distinguishes all bad philosophy from the only philosophy worthy of being called philosophy."[3-4]
Hegel saw that formal logic was not objective, but he did not understand the value of formal logic. In his Philosophical Notes, Lenin several times excerpted Hegel's criticism of the identity of the abstract and the concrete, expressing his approval. In Popular Philosophy, Ai Siqi bluntly declared: "We have long since declared the death of formal logic theory." "The thought of formal logic theory, though it cannot be said that it is not thought, is only thought of the lower order; Now that we have a higher logic of motion, we do not need formal logic theory." [2]