(1) perceptual knowledge is the necessary stage and premise of rational knowledge. The fundamental way to have perceptual materials is to participate in practice. Individuals can also use materials provided by others. Information provided by others can be a true reflection of things. Therefore, listening is not necessarily empty. (2) perceptual knowledge is the understanding of phenomena, which can be directly perceived through human senses. The phenomenon of things can be divided into truth and illusion, and illusion is not the true embodiment of the essence of things. Therefore, seeing is not necessarily believing. Phenomena include the philosophical truth of truth and illusion. "Hearing is false, seeing is true" means that what you hear is different from what you see. What you see can be true, but what you hear is often false. Don't believe what you hear without seeing it with your own eyes. But does it have to be true if you see it? Actually, not necessarily. Because things are divided into real images and virtual images, if the eyes see virtual images and mistake them for real images, they will mistake them for real images. (1) perceptual knowledge is people's understanding of things through the contact between sensory organs and objective things in practice. Perceptual knowledge is the foundation and necessary stage of rational knowledge, but many things and phenomena known by perceptual knowledge are chaotic, one-sided or even false, so what sensory organs feel and see may not be true. At the same time, there are truth and illusion, and illusion distorts and covers the essence in a negative way. It is impossible to understand things correctly only by perceptual knowledge or being confused by illusion. So "seeing may not be true" (2) There are two kinds of cognitive activities. Among them, learning cognitive activities is to learn what others have summed up. I heard it, but it may be true. Therefore, "listening is not necessarily empty" (3) specifically analyze what you see and hear, real and virtual, and what you see may or may not be true; What you hear may be false or empty. We can't generally say, "Seeing is believing, but hearing is empty".