Professor György Márkus systematised Marx's ideas about needs as follows: humans are different from other animals because their vital activity, work, is mediated to the satisfaction of needs (an animal who manufactures tools to produce other tools or his/her satisfactory), which makes a human being a universal natural being capable to turn the whole nature into the subject of his/her needs and his/her activity, and develops his/her needs and abilities (essential human forces) and develops himself/herself, a historical-universal being. Work generates the breach of the animal subject-object fusion, thus generating the possibility of human conscience and self-conscience, which tend to universality (the universal conscious being). A human being's conditions as a social being are given by work, but not only by work as it is not possible to live like a human being without a relationship with others: work is social because human beings work for each other with means and abilities produced by prior generations. Human beings are also free entities able to accomplish, during their lifetime, the objective possibilities generated by social evolution, on the basis of their conscious decisions. Freedom should be understood both in a negative (freedom to decide and to establish relationships) and a positive sense (dominion over natural forces and development of human creativity) of the essential human forces. To sum up, the essential interrelated traits of human beings are: a) work is their vital activity; b) human beings are conscious beings; c) human beings are social beings; d) human beings tend to universality, which manifests in the three previous traits and make human beings natural-historical-universal, social-universal and universal conscious entities, and e) human beings are free.