By studying the history of philosophy, we know that before Marxism came into being, the discussion about human nature had already been carried out. According to predecessors' viewpoints and self-combing, there are mainly three kinds of essentialism: the theory of innate human nature regards human nature as innate formation. For example, "human nature is good" and "natural bad habits"; The theory of natural human nature, that is, one-sided emphasis on human nature (human desire) determines human nature; Abstract theory of human nature, that is, talking about the convergence and eternity of human nature beyond class and historical development. None of these three essences scientifically reveals the true essence of human beings. Marx critically inherited the expositions of Feuerbach, Hegel and other predecessors on human nature, and creatively discussed human nature from three aspects: human object activities, human social relations and human needs, thus making a scientific definition of human nature.

Keywords: nature, all-round development, unity

"Labor is the essence of human beings". Marx expounded the essence of human beings in 1844 Economic and Philosophical Manuscripts, pointing out: "All the characteristics of a species and its class nature lie in the essence of life activities, while human class nature is only a free and conscious activity." [1] Here, human characteristics refer to human nature, while free and conscious activities refer to labor, in other words, human nature is labor. This is exactly what Marx explored the essence of human beings from their practical activities, that is, labor. As can be seen from this document, Marx discussed the objective activities of human beings, holding that human beings are a kind of "quasi-existence" and human nature is a kind of social relationship. Man is not an abstraction that exists outside the world. Man's development is inseparable from the nature of his life and growth. Without nature, he would cease to exist. We should look at people's essential attributes from their natural and social attributes. "Labor is the essence of human beings" is an important issue put forward by Marx and a profound summary of the essence of human subjective activities.

The essence of man is "the sum of all social relations". "The essence of man is not an abstract thing inherent in a single person. In reality, it is the sum of all social relations. " [2] From here, Marx explored human nature on the basis of social relations. This proposition means that Marx began to explore human nature from the historical and realistic social perspective. Therefore, Marx provided us with the idea of analyzing human nature based on real life and laid a solid foundation for the all-round development of human beings. What we need to know is that human nature must be explored from various "social relations" and can only be grasped and understood in the form of reflection, practice and re-practice. There is no way to talk about human nature without real people. It is not determined by one aspect of social relations, but by the sum of all social relations.

"People's needs are the essence of people". Marx pointed out that as a certain realistic person, you have rules, missions and tasks. It doesn't matter whether you realize it or not. This task is due to your needs and its connection with the existing world. The following is Marx's exposition of human nature from the perspective of human needs. He believes that the first premise of any human society is undoubtedly the existence of living individuals, and the first requirement of personal existence is to meet the needs of life. Human needs are the premise of maintaining human life activities and the motive force of human labor activities. However, if people want to carry out labor activities to meet the needs of their own development, they must form various social relations in practice. Therefore, in this sense, human needs, that is, human nature, are closely related to the above two definitions of human nature. Labor to meet people's needs leads to social division of labor, and social division of labor and people's position and conditions in the division of labor will be limited, thus making the exchange and consumption between people an inevitable demand, and then forming social relations.

How to understand people's all-round development?

Realizing people's all-round development is the core issue of Marxism and the ultimate goal of exploration. Marx put forward the idea of man's all-round development, including the all-round development of the whole "man" and "individual", and in this respect, he emphasized the all-round development of the individual. The core of man's all-round development is the full development of his physical strength and intelligence; Second, the free and full development of human personality (such as personality, talent, character, temperament, emotion, interest and other non-intellectual factors). In addition, the all-round development of human beings is a historical process. Marx once put forward that there are three forms of human development, that is, the development from low to high is divided into three stages: 1, and the natural economic stage, that is, primitive society, slave society and feudal society, which is a form of "human dependence". Individuals have no independence and are directly attached to a social entity. 2. The stage of commodity economy, namely "the dependence of capitalist things", is an independent stage based on the dependence of things. Although individuals have broken through personal dependence, they have fallen into dependence on things. 3. The "new stage" of free and all-round development, namely * * * production stage. This is the highest ideal realm of people's all-round development.

What is the content of man's all-round development? Some scholars believe that the all-round development of human beings refers to the general improvement and full development of human qualities and potentials in all aspects. "It includes not only the balanced development of morality, intelligence, physique, beauty and labor, but also the sound development of irrational factors such as personality psychology, personality, interest, will and temperament." [3] The predecessors refined the ideas elaborated by Marx and Engels in German Ideology, Manifesto of the Producer Party and Economic Manuscripts, and thought that the all-round development of human beings includes five basic contents: 1, the all-round development of human life practice activities. 2. All-round development of human needs. 3. All-round development of human social relations. 4. All-round development of human ability. 5. People's potential can be brought into full play. These five aspects basically cover Marx's narrative about man's all-round development. They are inherently unified in the all-round development of individuals and are indispensable.

The Internal Unity of Humanity and Man's All-round Development

The essence of man and the theory of man's all-round development are important parts of historical materialism, and they have internal unity. Specific performance in the following aspects:

Understanding that labor is the essence of human beings and the premise of their all-round development will promote the great progress of labor. On the one hand, Marx revealed that the essential attributes of human beings are sociality and practicality through the labor of objectifying activities, which is the fundamental sign that human beings are different from other animals. Labor includes three elements: labor subject, labor object and labor tool. Therefore, Marx expounded the all-round development and liberation of human beings from three aspects: the subject, the object and the tool of labor. The process of people's liberation and development is that people first engage in creative activities as free men, so as to meet their own needs, realize the essential requirements of people and become all-round people. Practice, as a unique activity of human beings, is the need and way of existence of human beings. Both human objective activities and human social relations are unified with practice. Because practice is human practice, animals have no purposeful practice. Therefore, people with initiative can promote their all-round development in practice. On the other hand, people's all-round development can better act on practical activities, thus changing people's essence. When people achieve all-round development (that is, great physical and intellectual development, full play of various potentials and adaptability to different labor needs), people's actual labor changes have changed, because people have been fully developed as the most active factor in productivity. And with the improvement of people's labor tools and working methods, labor efficiency and productivity have also been improved, so the whole purposeful and conscious actual labor has reached a higher level, which has also had an impact on human nature.

The essence of human beings is "the sum of all social relations", which is conducive to the all-round development of human beings and thus promotes the continuous enrichment of human social relations. This is a two-way interactive process. On the one hand, if we fully understand that human nature is "the sum of all social relations", we can promote the all-round development of human and social relations. Because the basic attribute of human beings is natural attribute and the essential attribute is sociality, the essence of human beings is inseparable not only from the relationship between human beings and nature, but also from the relationship between human beings and society. Because man is a person in society, everyone can't exist and develop independently without social relations, so man's comprehensiveness refers to the comprehensiveness of his natural relations and social relations, and man's comprehensive development means the continuous improvement, harmony and breakthrough of various relations in real life. We know that the universality of human relations is mainly reflected in the material exchange relationship, and then political, economic, cultural, ideological, moral, legal, ethnic and religious relations are established on the basis of the material exchange relationship, which all have an impact on human nature. With the rapid development of economy and the great progress of science and technology, the development of transportation has gradually broken through the geographical restrictions, making the communication between people more extensive and in-depth, and highlighting the dominant position of individuals. Understanding and developing human nature in social relations can promote the all-round development of modern people's sociality, and the interaction between everyone's development and social development is conducive to the all-round development of human social relations. On the other hand, when people achieve all-round development, all social relations of people will be greatly enriched and improved. People's political relations, economic relations and cultural relations have been fully developed, which makes relatively equal, where people have various rights and social status, and there is no longer oppression and exploitation. People's social relations will be unprecedentedly enriched and developed, thus affecting this essence of people.

Demand is the essence of human beings and the ultimate goal of their all-round development, which meets their various needs. Need is the internal motivation of people to carry out various activities and the ultimate goal of activities. In any case, individuals in society are starting from themselves and carrying out activities for their own goals. In order to pursue one's own nature, that is, needs, and find ways to meet one's own development, it is inevitable to have a relationship. This relationship includes all kinds of social division of labor, commodity exchange and consumption. From Marx's definition of needs, we can see that needs are not only purposeful and universal, but also eternal and dynamic. The process of human survival and development is the process of continuous transformation and development of human needs, including man and nature, man and man. Without people's needs, all human social practice activities and all social relations are out of the question and will become aimless. Therefore, people's essential needs are the most fundamental motive force and ultimate goal of modern people's all-round development. Only when people's needs are met can people's development be more comprehensive. On the contrary, when people achieve all-round development, people's needs will be greatly satisfied. Man's all-round development, that is, the great development of physical strength and intelligence, the full play of various potentials and the great improvement of spirit, so man's needs, including physical and psychological social needs, will be fully met because of man's all-round development. Moreover, human labor and social relations will continue to develop with the satisfaction of human needs. It can be seen that human nature and all-round development are inherently unified.

As an important part of Marxist theory, the essence of human beings and the theory of all-round development of human beings are inherently unified. Since it is an integral part of Marxist theory, we should fully understand, study and develop this theory, which is also the scientific attitude of Marxism. In addition, "once the theory is mastered by the masses, it will also become a material force." [4] Since there is an inherent unity between human nature and people's all-round development, we should fully realize this unity and use this unity to deeply understand human nature and better promote people's all-round development. At present, China is making concerted efforts to realize the Chinese dream of the great rejuvenation of the Chinese nation, which is also an unprecedented opportunity to realize human nature and all-round development. We should fully seize the opportunity and use the latest theoretical achievements of humanity and all-round development to contribute theoretical strength to the realization of the Chinese dream.