thermodynamics - Why does the nature always prefer low energy and maximum entropy?

Why does the nature always prefer low energy and maximum entropy?

I've just learned electrostatics and I still have no idea why like charges repel each other. http://in.answers.yahoo.com/question/index?qid=20061106060503AAkbIfa I don't quite understand why U has to be minimum. Can someone explain?

Answer

Nature has no preferences, and therefore entropy tends to increase.

Sounds paradoxical?

The point is that each microscopic state (describing the exact position and velocity of each atom in the system) is equally likely. However, what we typically observe is not a micro state, but a course-grained description corresponding to incredibly many micro states. Certain macro states correspond to far fewer micro states than other macro states. As nature has no preference for any of these micro states, the latter macro states are far more likely to occur. The evolution to ever more likely macro states (until the most likely macro state, the equilibrium state, is reached) is called the second law of thermodynamics.

The decrease of potential energy is the consequence of the first (energy conservation) and second (evolution to more likely macro states) law of thermodynamics. As macro states with a lot of energy stored in heat (random thermal motion) contain many more micro states and are therefore much more likely, energy tends to get transferred from potential energy to thermal energy. This is observed as a decrease in potential energy.