V.Kh.Vasilenko paid much attention to the development of philosophical aspects of the concept of disease and left the rich intellectual legacy and a number of advisory instructions that allow the main challenge in modern medicine (the definition of the notion of disease) to be addressed. One of his principal messages is the necessity of generalization and synthesis of facts. Following Vasilenko's instructions, Part 1 of this review is devoted to systematization of modern views of general features of pathogenesis of internal diseases for obtaining a deeper insight into the essence of the disease.