Plato designed an interesting cave fable in the Republic. A group of people are like prisoners, living in a cave for generations. The cave has a long passage leading to the outside, and people's necks and feet are locked, so that they can't look around and can only face the cave wall. There is a fire burning behind them. Between the fire and the prisoner, there were some people walking around with utensils, and the transformed image of the utensils was cast on the cave wall in front of the prisoner by the fire. Prisoners can't look back, don't know the reason of the images, think these shadows are "reality", call them by different names, and get used to this life. When a prisoner accidentally broke free from the shackles and looked back at the fire, he found that what he had seen before was an image rather than a real thing; When he continued to work hard and walked out of the hole, his eyes were stimulated by the sun and he could see nothing but nothingness. He had to go back to the cave, but he also regretted it. He hated himself for seeing everything clearly because it brought him more pain. Plato tells us through this fable that truth and justice are hard to find, but we can't give up the pursuit and the consciousness on the other side. On the contrary, Plato has not forgotten to remind us that the prisoner's dilemma is against justice, but when justice itself is a nihilism and an unreachable shore, how can we easily give up this ignorant shore? Instead of this, it is better to live in the pursuit of the other side, even if the other side is a kind of nothingness. Therefore, what matters is not the other person, but the pursuit itself. Plato also told us that it is not terrible to return to this shore and to the cave. The terrible thing is that when we understand the outside of the cave and recognize the nothingness on the other side, we will return to the cave and this shore. There is nothing outside the cave; There is a load inside the hole, a vacuum outside the hole that can't tell the direction, and a self-evident load inside the hole; ..... In fact, outside the cave and inside the cave, although the weight is different, they are all unbearable. Ai Wu's "Deep Breathing" series vividly metaphor this profound fable. He tried to ask the world: should we go out of the cave or go back to it?