subjective world will gradually increase. The course that the logical construct gradually increase its attributes and getting orderly is the forward evolutionary process of logical construct and culture gene.[4]

Ⅳ. The Theory of Concept

1. Abstraction

Abstraction is a kind of thought game, which is characterized by focusing only on some properties of things and ignoring others. For example, Chinese people have male and female, old and young. I only care about whether you are Chinese, do not care about you are male or female, old or young, that is abstraction. Commonness is the abstract of many materials, and the law is the abstract of many events.

There are different degrees of abstraction. More abstraction means fewer properties to focus on and more properties to ignore. Concrete and abstract are opposition, the less degree of abstraction means more concrete. All objective things are concrete beings with infinitely multiple properties. Human cognition can only focus on some attributes, so all human cognition is abstract.

Simulated products have some of the same attributes as the object, and some of the attributes are different from the object. We tend to only pay attention to the same attributes, do not care about the different attributes. Then the simulated product can be regarded as an abstract of the simulated object.

2. The Simulation of Event, Material, Law and Commonness

In the objective world, there are events, materials, laws, commonness and relationships. Event is the movement and changes of material and relationships. Logical construct comes from artificial simulation products. Logical constructs can simulate all events, materials, laws, commonness and relationships.

A car is a concrete material, which can be simulated by words, images and other symbols to form a logical construct about the car. An event can also be simulated, that is to describe the event by words, images and other symbols. For example, to describe the process of accelerating and overtaking of a car, or describe an ancient story.

The simulation of objective laws is the scientific exposition of various theorems, axioms and principles. However, we cannot directly observe the objective laws, so we cannot directly simulate the objective laws. We can only observe events first, and then abstract the commonness of the events, we regard the abstract result as the simulation of the objective law.

All cars have wheels, which is a commonness. The description of this commonness is a logical construct. The commonness come from abstraction of individuals rather than simulation of objective commonness, which cannot be observed. In the process of abstracting events and individuals, there are many guesses and assumptions.

The relations of objective things includes time relation, space structure relation, same, similar, function relation and so on. Many simulations of relations also come from guess and assumption.

Materialists and Objective Idealists are wrong to think that the knowledge of objective laws and commonness comes from the simulation of them. We have never seen objective laws and commonness. We can only see individual things and events one by one. Since objective laws and commonness cannot be observed, they are never the criterion of truth. If we could see the objective law, then we can see whether our knowledge is right when we compare the objective law with our knowledge. But we cannot do that. The usefulness is the criterion of truth. Our knowledge of objective laws is considered to be true if it brings benefit when applied to practice.