This article develops the system paradigm formulated by J. Kornai, seeking to combine it with general systems theory and a space-time approach to the analysis of economic systems. According to the proposed concept, the time and space available to an economic system are considered its primary (basic) resources; this allows the resource-based view of the firm to be extended to a broader range of economic systems. The article provides a qualitative taxonomy of economic systems based on space-time boundaries, whereby all economic systems may be divided, with varying degrees of definiteness, into four classes: object, project, process and environment systems. It is shown that the smallest stable unit that is sustainable in the long run is a tetrad — a group comprising four economic systems (each of the above types) that perform their functions and exchange both time-space resources and the capabilities of using them effectively.