The 2nd Law of Thermodynamics says that the entropy of an isolated system increases over time. Which, in plain English, means order turns to disorder and everything comes to an end.
The universe is assumed as a closed system because it is not contained in anything. Instead, it contains everything. And yet, rather than just disorder increasing all the time, everywhere the universe teems with complex structures such as stars, planets, ecosystems, life forms, etc.
The reason is that a complex system is essentially a dissipative structure that stays far from thermodynamic equilibrium by constantly taking energy from its environment. Complexity needs Energy to come into existence, sustain itself, and propagate further. Maintaining and building complex structures takes work. And it’s the flow of energy that causes work to be done.
In Thermodynamic Equilibrium energy is equally distributed and entropy is at its maximum. There is no energy gradient and hence no energy will flow to get work done. However, all complex systems keep themselves away from Thermodynamic equilibrium by doing work – plants do photosynthesis, animals feed, and humans eat. We need the Energy to keep us alive. It is programmed in our DNA to seek out more energy to keep us going. And this rule does not just apply to humans but also to the first living thing that evolved billions of years ago. The entire cycle of evolution by natural selection is a mechanism to keep self-replicating complex structures going.
Organisms take in new energy to keep themselves far from thermodynamic equilibrium, but the overall trend of entropy in the universe is constantly rising. Why is this so? It is because as organisms take more energy, and perform work to gather more energy, some energy is always wasted. Thus, in the universe as a whole, energy is dissipated and slowly but surely evenly distributed. So, complex structures (including living things) are essentially entropy factories.
The 2nd Law of Thermodynamics is akin to the Law of Karma. If we don’t perform the Karma, we die. And even if we do perform Karma, we still die eventually. That goes to the heart of what it means to be living. And then this idea can be further extrapolated to our society as a whole. The vast complexities that sustain our lives and conveniences require us to extract matter and energy from the environment. And, even if we use the most eco-friendly way of existence even then some energy will be dissipated and increase the entropy of the universe.
This is a fact.
At the core of many issues and problems, we have faced and are facing, is this need for matter and energy to sustain or increase our complexities. Because ultimately, on a time scale long enough, the 2nd Law will prevail. Organisms will die, societies will collapse, and empires will wither away. The universe too will march on towards a heat death finally achieving thermodynamic equilibrium.
When viewed from such a lens, we realize that the wooly mammoth, the cavemen, great empires now ruined, the myths of civilizations, burnt-out stars, and the black holes of deep space all have a commonality. They are all complexities participating in the long-lasting struggle for existence.
And from this great fundamental strife descends all other strifes of which our numbered limited existence is just one small insignificant footnote. We can be the best poker player, but eventually, the house wins.