The article is devoted to the study of the fundamental principles of economic development at the regional level, with the aim of further improving and adapting them to the needs of economic development of territorial and economic systems at various administrative levels and ensuring the ability of the entity to achieve the planned economic result. The article examines conceptual approaches to the economic development of territorial-economic systems based on fundamental philosophical concepts. The trinity of information, energy, and matter (as components of the material world) is considered in the implementation of economic development of territorial-economic systems from the perspective of the concept of “Things, Properties, Relations.” A connection between modern economic theories and fundamental philosophical concepts is established. The potential for improving regulatory and legal documentation by increasing the attention paid in official documents to issues of economic development at the regional and basic levels is identified. The author’s approach to considering models, mechanisms, and instruments of economic development is proposed, which is based on the functional combination of approaches of philosophical concepts in accordance with the phase of economic development, taking into account the properties of the subject of economic development to carry out the transformation. The dialectical interdependence of the development of the subject and object of economic development in the process of interaction is considered. Two formulas for implementing economic development are proposed, based on deductive and inductive approaches to initiating change, which are characterized by differences in the sequence of development phases, depending on the identified properties of the development subject and its ability to determine and evaluate the properties of the object. The mechanisms and instruments of economic development at the regional level that need to be studied at further stages are identified. The crucial role of the existential approach in development planning, particularly in the context of post-war recovery, is identified. 

territorial-economic system, economic development, regional development, theoretical-conceptual approach, philosophical concepts, deductive model of economic development, inductive model of economic development