2.Knowledge is a Kind of Simulation

People's knowledge of the world is also a kind of simulation, the content of knowledge is a fake simulated product compared with the object of knowledge. The material of this simulation is not plastic, ink, nor sound, light, electricity, but ideology. When I see a real car, I create a model of the car in my mind, which is similar to a photo or a computer simulation.

Some of the structures and properties of this mental model are the same as some of the structures and properties of the objective real car, and some of the structures and properties are different.

The name of the simulated product is determined by the same attributes of the simulated object and the simulated product. A toy similar to a car is called a toy car, referred to as a car. A toy similar to a pistol is called a toy pistol, referred to as a pistol.

The name of the cognition is determined by the same attribute of the human cognition and the imitated object. The knowledge similar to the car is called the knowledge (or experience, phenomenon) of the car, referred to as the car. The knowledge similar to the pistol is called the knowledge of the pistol, referred to as the pistol.

Cars and pistols as cognition are not real cars and pistols, but Materialists and Objective Idealists regard them as real cars and pistols. When you stand in front of me, I don't see you as you really are. What I see is my knowledge. My knowledge about you may or may not be the same with you. So Marx's motto was "Doubt everything".

Materials such as plastic and iron are suitable for children's toys because they are cheap, easy to play with and not dangerous. Materials of photo are paper and ink, so photos are small enough to be printed in large quantities, easy to be mailed and carried.

So the simulated product and the imitated object must be different, if they are exactly the same, they can not meet the needs of people. A photo of a building can go in your pocket, but a real building can't. Simulated products and simulated objects are always two fundamentally different things.

The materials used for human cognition are the products of thoughts made by the nervous system in our heads. The nervous system is something everyone is born with, and it costs nothing. Therefore, human's understanding of the world and the objective world itself must be different. If they are exactly the same, they can not meet human needs. The understanding of the world is always something fundamentally different from the objective world itself.

People's cognition can influence people's practice. Since some properties of cognition about cars are the same as those of real cars, this cognitive model can lead to correct practice. But the cognitive model doesn't have much in common with the real car. The real car is very complex. The cognitive model can be very simple. Due to the limited ability of memory, learning and thinking, it is difficult for people to apply the complex cognitive model. The simplification of the model is conducive to practice in many occasions.