Schrödinger's cat is a famous paradox in the field of quantum mechanics: a cat, some radioactive elements and a bottle of poison gas are enclosed together in a box.Within one hour, the probability of decay of radioactive elements is 50%. If it decays, a hammer connected to the Geiger counter will trigger and break the bottle, release the poison gas and kill the cat. Because of the equal probability of this happening, Schrödinger supposes that the cat in the box is considered dead and alive before the box is opened.

We generally think that when no one was watching, the particles in Schrödinger's box had either decayed or not decayed—there must be one of the two. However, this does not meet the requirements of quantum mechanics. If there must be one, quantum mechanics can not explain the double-slit interference experiment and cannot explain the wave-particle duality of particles. Quantum mechanics believes that the particles in the box are in the superposition state of the decay and no decay states.

The fact that we cannot understand quantum mechanics means that it cannot meet the criterion of truth of logical unity. Fortunately, this standard is not the fundamental standard of truth, but an alternative standard. The fundamental criterion of truth is practicality. The role of theory is to improve people's practical ability. When the formula of quantum mechanics can help people solve practical problems, we can believe it is true.

The alternative standards for truth include prediction, stability, simpleness and logical unified. The fact that quantum mechanics can accurately predict many experimental results shows that it satisfies the predictive criterion, the fact that it can use simple formulas means that it satisfies the criterion of simplicity, and it can withstand practical tests for a long time shows that it satisfies stability criterion. So in the five standards of truth, quantum mechanics meets four, only one is not satisfied, and we cannot find a better theory than quantum mechanics. So 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. If the collapse of macroscopic things could be observed, all macroscopic things would have no quantum properties. If one day our observations were fine enough, then the quantum cat's conflict would not exist.

Waves and particles are two completely different substances. Quantum mechanics tells us that matter has wave-particle duality, which makes it difficult to understand, but standing waves may help us to understand. The standing wave is a kind of wave at first, but it is fixed, like a ball, and the ball is a particle. The standing wave can behave like a particle. The condition to change from a normal wave to a particle is the phase change of the wave. As long as the phase is appropriate, the wave can become a particle. When the phase changes slightly, the particle disappears. The positive and negative particles may be annihilated in this way. One electron can pass through two gaps at the same time, because the electrons themselves are waves.

The above explanations of standing waves and probabi- lities are concrete ways to solve the contradiction of quantum mechanics. These approaches are tentative. Scien- tists have also proposed many other tentative theories. It is still unclear which of them will succeed.

Objective things are concrete, and theories are abstract. There is always an insurmountable gap between theory and facts. When the theory can successfully solve practical problems, we will ignore this difference and feel that the theory and practice are completely consistent. In fact, this is only an illusion.

The formula is an integral part of the abstract theory. The formula can describe the reality, but can the formula be transformed to describe another reality? The super- position and entanglement states of the quantum are the result after formula derivation. Is there no problem in formula derivation? Is there any conditions? Newtonian mechanics formulas are used and deduced by countless people. No problems are found, but this does not mean that it is really problem-free.

All theories are man-made hypotheses. Since it is a hypothesis, it is not the true face of the objective world but a false one. The hypothesis has been tested and we believe that it can become truth, but the problem is that truth may be overturned in the future, that is, the truth is still not true. In this sense, all truths are false. Laozi said: “Truth can be say, but it is not the real truth.” So we can assume that the so-called superposition of the alive cat and the dead cat is not real in reality.

It should be noted that some people now confuse the non-decisiveness of microscopic particles with the non-decisiveness of consciousness. For example, Christian List, a philosopher at the London School of Economics and Political, said, “If a level is deterministic, it can be completely non-deterministic at higher and lower levels.”

People have free will, because people are complex systems, proteins have huge molecular weights, their structures and functions are extremely complex, and people's organs and nervous systems are more complex. Scientists do not know how the brain works, so we can only admit that the brain has free will. However, microscopic particles are simple systems. Recognizing that a simple system has free will is totally a betrayal of the scientific spirit. No matter how difficult it is to solve the task of quantum mechanics paradoxes, we cannot admit that a simple system is free. With the advancement of science, the non-determinism of biology and human will gradually disappear. Our understanding of biology and people is increasing. Many things that used to be considered living and free have gradually become dead. When we can accurately describe the working process of the brain, we can say that people are machines.