New knowledge belongs to public goods. First, because it is non-competitive, once it is created, adding a new user will not affect the use of others. Second, because it is non-exclusive, people can use it once they get it, whether they pay or not. Therefore, if the patent system is not implemented, private individuals will not have the enthusiasm to create inventions and generate new knowledge. The implementation of the patent system can prohibit others from using new knowledge during the patent period, making non-exclusive new knowledge exclusive. From the perspective of market efficiency, its advantage is that it can protect and encourage private innovation and promote the production of new knowledge, but its disadvantage is that it will limit the full use of new knowledge to a certain extent. But compared with the two, profit is the main thing.