Life and forms of living beings began around 4 billion years ago. However, the terms stocks and stores have only developed as scientific concepts over the course of the last two centuries, while the term fund came into use even more recently (Georgescu-Roegen 1971). A fund can be understood as a source of services for one or more species of living beings.
While Mainstream Economics does not focus on the origins of life, this is a basic concern of Ecological Economics. To understand life, we need concepts which focus on its temporal structure and are suitable to examine the interaction between the dynamics of coupled systems, made up of natural and economic components.
A central concept is that of a stock, hence this concept develops a general theory of stocks, applicable in ecology and economics. Some stocks are used as stores in ecosystems and economic systems. Crucial questions for sustainability are: When do stores become scarce? How can they be replenished or substituted by other stores? To answer these questions, we need a third concept, a fund. Essential for a fund is that it maintains itself, and that it gives services to other living beings. Take an apple tree, for example. Its services are material and immaterial, be they shelter or aesthetic services. Drawing on three other concepts a Teleological Concept of Nature, Thermodynamics and Irreversibility, enables us to operationalize the concept of life. This concept helps us grasp the intertemporal relationships between stocks, stores and living beings.
As a practical example we use the three concepts to examine the development of oxygen in the atmosphere and its consequences for life on earth.