Two understandings: 1. An unattainable expected goal is illusory. Authenticity refers to the violation of the laws of nature, which cannot be realized and forms a correct rational understanding related to it. For example, the idea of perpetual motion machine is illusory, which makes it impossible to realize perpetual motion machine, and it is a real understanding that violates the law of conservation of energy. 2. The existence and expression of illusory things are still based on reality, and the factors and links involved either exist in reality or do not exist in reality. This is indeed a response and appeal to some objective existence. For example, the literary work "The Duke Living Buddha" is not only the dissatisfaction with the gap between the rich and the poor, but also the yearning for a better life, which is also true.