First, let's do an experiment: close one eye and gently press your index finger on the eyeball of the other eye. Even if you sit still, many people will feel like the world is shaking. It's easy to feel dizzy. This simple experiment shows that our perception of the external world is actually created by the vision process in our brain and other sensory processes. What we experience is not the world itself, but a construct of our brain: the world for us. This design is extremely effective: for example, the world appears still even when we turn our heads, although the image on the retina changes rapidly. The visual image we perceive is tailored to our needs. For example, when we look at an object, we perceive it as having outlines. However, the contours are not present in the light hitting the retina, but are an addition created early in the visual process. It is a common belief that the visual process works like a camera. However, it is easy to show that this is not true. For example, when we look at something, we feel that everything is quite sharp. But in reality, only two angular degrees of the visual field are acute, about two fingers at arm's length; on the periphery we see things blurry, where it is more difficult for us to perceive colors. But every time we look at something, it becomes sharp, and so we have the illusion that the entire field of vision is sharp. Another illusion is that we do not perceive any gaps in our visual field. But there is an area of ​​the retina that does not have receptors; A blind spot means that there is a part of the visual field in which we cannot see anything. This could be a possible explanation for why we sometimes miss things in the world around us when we think we've looked. Looking and not seeing is often the cause of traffic accidents. If my perception of the world is an illusion, then what does the world really look like? It doesn't look like anything at all. There is nothing that can be seen, heard, smelled or felt unless there is a brain to create the experience. Nature itself is colorless, soundless and odorless; it is simply the movement of matter. Our senses give it content. The brain is not a passive recipient of images and sounds from the world around us. He actively looks for patterns and interprets the world around him. Our perception of the body is also a construct based on feedback from the senses. The brain not only improves, it also invents. Try crossing your middle finger with your index finger, and then feel the tip of your nose. Feels like you have two noses. The explanation is that the outside of the middle finger usually does not touch the same object as the inside of the index finger, which causes the brain to create the perception of two objects. Let's continue with our illusion experiments. Stand next to another person, place your right index finger on the other person's nose and close your eyes. Then ask the third person to slowly move their index finger up and down your nose while holding their right index finger and moving it across the other person's nose in sync. After a while you will feel that you have a very long nose. Because the movements are simultaneous, your brain assumes that what your index finger feels is in the same place as what your nose feels, creating the illusion of a long nose. As a result, you do not perceive the body directly, but a virtual body created by your brain, just as you see a constructed world rather than the real one. A similar phenomenon can occur in people with so-called phantom limbs. A phantom limb means that after an amputation you feel an arm or leg that is no longer there. The phantom limb itself is the result of the body model continuing to simulate an arm or leg as part of the body, despite the lack of real feedback from?