What is information? Every people feels it is difficult to explain it clearly, even Norbert Wiener who is honored as the founder of cybernetics. He sighed, “Information is information, neither matter nor energy.” Meanings of information are in chaos now. Information is mixed with signal, symbol and consciousness of information together, difficult to be distinguished. Conception of information is not scientific, which can cause a lot of troubles and mistakes to scientific research. Herein, I would strictly distinguish three definitions of information.

Le'on Brillouin said, information means negentropy¹. As disclosed by Stefan-Boltzmann law, entropy is of direct ratio to logarithm of number of complexion. It means that the state with large number of complexion is balanced one, the state with small number of complexion, i.e. negentropy, corresponds to broken symmetry of structure. If informa- tion is negentropy, information is broken symmetry.

Broken symmetry has two divisions: matter and con- sciousness. When I don't know what is in cup, I guess that there may be a fish, a frog or a cup of solution and so on inside. When I consider there is a fish in it, it means that I deny possibility of other matter in the cup. This is the broken symmetry of consciousness. The broken symmetry of matter also has two divisions: one is broken symmetry of signal and symbol; the other is broken symmetry of matter other than signal and symbol.

For example, when there is a fish in cup, if I place a tag at the side of cup and write a word “Fish” on it, the word is a symbol which is also a broken symmetry. Because word “Fish” has been written, it means that I didn't write other words, e.g. “Horse” or “Cow”, etc.

Now, meanings of information talked by people are in high chaos. Sometimes, it means broken symmetry of consciousness, “Information is know-how.”; sometimes, it means broken symmetry for signal and symbol, “Information is signal, data and advices”; sometimes, it also means broken symmetry of matter other than signal and symbol, “information is uneven distribution of matter and energy at time and space, and difference or variation of being” ². The three definitions shall be partitioned strictly as they have completely different attribute. One computer program written on paper is broken symmetry of symbol, but compute doesn't know this program. Sequence of electric signal generated by knock on keyboard is broken symmetry of matter, which is such information as able to be recognized by computer. The word “Fish” has different attribute from actual fish. Fish can be eaten but the word is unable to be eaten.

If one person has two names, it is no matter. For example, Mao Zedong is also called Mao Runzhi, either one can be said without misunderstanding present. However, it would be trouble and liable to causing misunderstanding if two people has a same name. Thus, name of people is always not scientific language. Administration gives every people an ID number which is exclusive and would not cause any misunderstanding. Therefore, ID number is scientific language.