All life on Earth depends on energy, and the transformation of energy from one form to another. On Earth most energy comes from the sun, although some energy comes from the internal heat of the earth, and the tidal interaction of Earth and Moon. All human social life depends on gathering and transforming energy. For most of human existence this has involved collecting and hunting food, and sometimes transforming the ecology to be better for the production of food. Food is our basic form of energy, it allows us to do everything else that humans do.

Energy is hard to define, but it manifests in changes in changes in systems, and is seen in transformations. It is often defined as ‘work’ or moving something from one place to another against resistance. In that sense energy is the basis of economies and of social life. The old idea of the “Labour theory of value” goes back to a time when human labour was the main source of energy, and hence the main source of ‘work’ and ‘products.’ Nowadays we have other sources of work and energy. Energy availability and directability heavily influence what can be done.

It might be suggested that we have at least four interacting sources of value: the energy expenditure in making something, the return something fetches on a market, its use in promoting further energy expenditure, and the measure of destruction or pollution that it brings about.

The laws of thermodynamics are also important. Firstly, energy can neither be created nor destroyed (the total energy of an isolated system is constant). There is no energy available to humans without previous energy expenditure – for example creatures cannot even gather food without energy expenditure of some type, so the energy expenditure in gathering food and processing food has to be less than the amount of energy which can be released from the food, or else the system will collapse. We call this ratio Energy Return on Energy Output. Secondly, in a ‘closed’ system the dissipation of energy in random motion or heat, will increase over time. In other words energy is dissipated into the system, in the sense it cannot be directed, or retrieved.  This dissipation is called entropy. Every time energy is utilized, moves or produces changes, some directable energy will be lost. Energy is lost when energy is used. Energy dissipation may also act to disturb, disrupt or alter the systemic contexts. Again life functions, because the Earth System is open to the sun.

All societies, all ecologies involve

  • Gathering energy
  • Releasing energy
  • Using energy to transform the world and be transformed.
  • Dealing with the waste and destruction that the energy usage enables.

Hence the study of energy usage and transformation is fundamental to the understanding of society.