Logical judgment is not necessarily the truth. Logical unity can be used as an alternative criterion for judging truth, but it is not the final criterion, the final criterion is practice and value. For example, the conclusions of quantum mechanics work well in practice, but are illogical. On the contrary, the content of judgments and reasoning may be wrong, but these wrong judgments and reasoning may be logical. For example, all crows are white birds, and the bird I saw today is black, so it can't be a crow. The main premise and conclusion of this reasoning are wrong, but the process of this reasoning is not logically wrong.

2.2 Extended Meaning of Logic

In the mechanical craft class, teachers often tell a case called hollow ball. A designer designed a hollow metal ball, after drawing let the factory make it out. The factory worker said he could not. If the two hemispheres were processed separately and then assembled together, they could be hollow, but how could the hollow part inside a complete ball be processed? How did knives get in? If it was cast, how did the sand core come out? It was not logical, it was easy for a designer to draw such a ball on a drawing, because the drawing was fake and could ignore the logic of everyday life, but to actually produce a real hollow ball, it must be logical.

So what's the logic here? The worker at the factory may not have studied logic, but he knew it was illogical. The logic he spoke of was his experience, processes of production that he had repeated thousands of times. There were some technical specifications in these production processes, and when the worker thought about production problems, he always followed these specifications, and these specifications became the rules of their rational thinking, so he calls these specifications logic. In fact, this kind of logic is not logic in the real sense, it can be said that the extended meaning of the concept of logic, this kind of logic can be violated.

Many new technologies will change the relationship between things, breaking past norms and making people feel illogical. It is not illogical, the logic that is the basic norm of rational thought has not changed. The magician's performance makes it seem illogical, a living person can be squashed. If a magician can do it, it must be logical. It's just that he hides some of the middle and props, which makes it seem illogical. In life, we treat the relationships between common things as rules that cannot be broken, and then treat these rules as rules of rational thought, and call these rules logic.