no matter whether we understand it, we have to accept quantum mechanics. Problems that it cannot be understood can only be solved by other methods.

In the history of science, in addition to quantum mechanics, many theories were once unfathomable, and most of them were later understood. The unfathomable state is the opposition state of contradiction. It turns to unification when it is understood. The unification is achieved through some certain concrete ways. What is the concrete way to unify the contradictions? For example, when cars go through the crossroad, the north and the south cannot go when east and west go. This is a contradiction. However, the contradiction is unified on repairing an overpass, the overpass is a concrete way to achieve the unification of contradictions. If some people has never seen an overpass in the past, when you tell them that cars can go north, south, east and west at the same time, they would think it impossible. Human imagination can develop with intelligence and practice. If we do not have enough imagination, it is difficult to find these concrete ways. Now we cannot understand the contradiction of quantum mechanics, probably because we still lack imagination. Einstein believes that quantum randomness, like all other types of randomness in physics, is the result of some deeper processes behind it.

The hypothesis for these deeper processes is not entirely absent. People have already proposed many possibilities, but they are still not mature enough. For example, quantum properties are based on probability because they can not be seen. Probability is an abstract description of facts. There is an essential difference between probability and fact. The distribution of the impact point on the target during shooting can be described by probability, but after a gun hits the target, its probability in this position must be 100%, and the probability in other positions is zero, ie, the probability collapses. The motion of microscopic particles can not be observed in detail and can only be described by probability. Therefore, we cannot know what the microscopic particles' motion and attributes will be.