EN
The subject matter of this dissertation includes the aspects of complex bodies i.e. mixed one in Aristotle's treaty 'On Coming-to-be and Passing-away'. The essence of the complex body is the formal cause updating it and indicating the state of the organization of elements, along with the material cause (elements). The essence form of a complex body differs form the essence form of its elements. Complex bodies are created by means of mixing elements. The mixture of the elements is a merger of its ingredients that have been mixed.