When you see the sentence "The moon itself does not shine, it is the sun that shines." If you have not thought about any of the above issues at all, then this sentence will have no meaning to you. It is nothing more than a proposition, an interpretation, an assertion, something like "Sheep in Scotland are black." It has nothing to do with you. It describes an object you don't care about. You trust this statement and accept it because you are convinced by the authority of books or other people, not because of any rational thinking. This sentence itself is knowledge possessed by human beings, but it is not your knowledge. In this case, it would be wise to adopt the same attitude as Sherlock Holmes.

The things we care about in science have countless forms and many properties. For example, if we stand on the shore and look at the sea, we will see: there are sea water, crashing waves, splashing foam and turbulent waves, as well as the sun, light, blue sky, white clouds and the flow of air ——The wind; there are grains of sand on the seashore, rocks of different colors and hardness; there are floating creatures in the sea, living and dying; finally, there are us observers standing on the coast; there is even happiness and nostalgia. Isn’t there such a variety of things and influences in other places in nature? Everywhere is complex and varied. Curiosity drives us to ask questions, to connect things, and to understand their manifestations as the result of perhaps a smaller number of elementary things and interactions combined in an infinite number of ways.

The purpose of creating physical theory itself is to link a large number of scientific facts in an orderly manner, point out the causal relationships behind them, and abstract shorter diagrams to describe more details of nature. Physical theories without detailed knowledge are meaningless, even theories such as relativity and quantum mechanics that are completely different from real experience.

Nature is a whole. Scientific facts (detailed knowledge) are never isolated but are linked to other facts through theoretical frameworks. The process of trying to make this link is a process of deepening understanding.