The modern civilization that originated from the Industrial Revolution is now spreading throughout the world. The demand for natural resources is rapidly increasing and the environmental problems are getting globally more and more serious. Our civilization seems hardly sustainable. What should we do to make it sustainable? This series establishes the fundamental theory of civilization, analyzes the problems of resources and the environment in terms of entropy, and suggests a solution to them.

Most of people believe that material recycling is the true recycling and thermal recycling is a fake. But the conventional material recycling is actually downcycling, whereas thermal recycling by the gasification system can realize more radical recycling. That is to say, what was thought to be the genuine recycling is deceptive, whereas what was thought to be the deceptive recycling is genuine. This recognition leads to reconsideration of the role that the government must play to promote recycling.

Clausius, one of the main founders of the modern thermodynamics, is the originator of the term “entropy,” but before this coinage he used an expression “equivalence value of transformations” instead. The term “entropy,” which is now used as a physical term, was originally economically conceived as equivalent value of exchange. Thermodynamics itself was a field of physics that was economically motivated to improve the thermal efficiency of heat engines. So, it was half physics and half economics. Apart from Clausius’s interest, the term has now become an important keyword for solving the environment and resource problems.

A heat engine is a device that repeatedly converts thermal energy into kinetic energy. It needs the difference of temperature and a working substance with a high rate of expansion to do useful work for us. It can be done in two ways: utilizing the change of volume of the working substance that hot and cold reservoirs make alternately expand or compress, and utilizing convection that the change of density resulting from the change of volume causes. A heat engine is not confined to an artificial one. The Earth also does useful work for living systems as a heat engine. The heat engine whose hot reservoir is solar radiation heat maintains the circulation of air and water, while the heat engine whose hot reservoir is geothermal heat maintains the circulation of mantle and mineral nutrition.

The shortage of natural resources and the destruction of the natural environment are two colossal problems that are now threatening our existence. These seemingly two problems are just one problem ― the problem of entropy. On this page, I will show that the essence of the two problems is entropy and that the key to resolving them consists in how to decrease entropy. So, first, let me explain what entropy is.

Economists usually consider consumption opposite to production. From the viewpoint of entropy, however, there is no difference between them. You can describe both of them as an increase in entropy of environment in compensation for reducing the entropy of a system.

Is moral value, as some theories of ethics insist, different from economic value? Should the moral value always override the economic value?

What makes merchandise valuable is usefulness and scarcity. Air is useful, but has no value, as anyone can get it easily. Trash is, even if it is very unique and hard to obtain, valueless, as it is useless. What then do both have in common?

The question "What is time?" has been an eternal problem for philosophers. However, you can define a physical time by making the second law of thermodynamics analytic. How can we define the time in our mind, then?

In this article, I define what life is and assert that social systems are also life by the definition. I will show in what respect societies are living things.