Philosophy can not develop without these problems thoroughly solved, just as religious philosophy and scholastic philosophy must be completely abandoned, their values are only historical values. Although some of them have important inspirations for the development of modern philosophy, they must not be allowed to resume. Many concrete theoretical achievements of objective idealism have a certain theoretical value, but their basic viewpoints are totally wrong and they cannot be tolerated. Understanding the essence of objective idealism is a necessary condition for the development of philosophy ontology. But now objective idealism is still powerful, not only do many great philosophers insist on objective idealism, but many subjective idealists (including many schools of positivism, pragmatism, and analytical philo- sophy) and materialists often slip towards objective idea- lism unconsciously.

Realism is opposite to nominalism. Nominalism holds that abstract things are not objective, they are the consciousness in people's minds. This notion of nominalism is correct. The objective world has only concrete things and no abstract things.

On the other hand, objective idealism also has many positive contributions to the development of philosophy. All scientific theories need to be constructed, and philosophical theories also need to be constructed. Construction is subjective fabrication and requires imagination. Objective idealism constructs many concepts and theories. Although most of them failed, this imagina- tion is very valuable. Objective idealism provides the conditions for the development of materialism and subjective idealism. The various concrete theories of objective idealism are often instructive. For example, Hegel's dialectics has positive significance for the development of dialectical logic. Leibniz's monad has positive significance for the development of system theory. It's like some children's drawings, lines, colors, and proportions are very naive and absurd, but there are places that give people inspiration and can't be seen in adult paintings. Therefore, the objective idealism can not be completely negated, and after pointing out the nature of its consciousness, we should carefully analyze the valuable elements of its theory. At the same time, it should be noted that the theory of objective idealists is not all of objective idealism, and they are often incomplete. Each philosopher's writings contain many fields and topics, many of which are not ontology.

When we observe the objective things, we will have a corresponding experience. Then we process and transform our experience and generate some ideas. These ideas have been different from the initial experience, and their counterparts may not be found in the objective world. And people have a strong imagination, can imagine and make up a lot of things out. These transformed experiences and fabrications made out of nothing are completely content of conscious world. They are subjective and non-objective. The experience produced by observing the objective world is also awareness, and it has some same characteristics as those fabricated by the imagination. Therefore, people often cannot distinguish. Experience is corresponding to the objective things, so people regard the purely subjective consciousness also corresponding to the objective things. The ancients people