Man plows the earth or forges iron, flies a fast-rushing plane or operates a patient, studies the structure of an atom or paints a picture - always and everywhere he deals with certain bodies (objects, things). There are many material objects in the world. The sun and other stars, earth, water, air, coal, metal ores, light, electricity and other objects of inanimate nature, hundreds of thousands of different species of animals and plants, finally, people and the factories they built, cars, residential buildings, household items - all this, taken together, and forms the world around us, i.e. nature and society.