Two most important questions in social science are what drives political, economic, and social changes and where the human society is heading. The arrow-of-time coined by British astronomer Eddington refers to our daily experience that time only goes in the forward direction and never in the backward direction. The arrow-of-time phenomena are ubiquitous in both the human society and the natural world. This paper proves that the physics concept of Goldstone boson or hydrodynamic mode is the key to understand the arrow-of-time phenomena in social science, analyze the important drivers of political, economic, and social changes, and answer the question what is the future of the human society. In the condensed matter physics, Goldstone bosons are hydrodynamic modes characterizing the long-lasting fluctuations around the equilibrium state. Hydrodynamic equations, which govern the mathematical description of the behavior hydrodynamic modes, are also the same equations that describe the dynamics of the condensed matter system. In a previous paper, we proposed that the most stable political structure in any nation is an equilibrium state of the political structure, which is characterized by 16 democratic principles. These democratic principles are the Goldstone bosons or hydrodynamic modes of human societies. This paper will examine these low frequency long lasting global mega trends in detail and quantify these political, economic and social movements with the indexing methodology. In statistical physics, there are only a handful of identifiable hydrodynamic modes in any condensed matter system, and it must be also true for the human society. This paper reaches a very surprising conclusion that despite the complexity of human society with billions and billions of changes every day, the only important driving forces of the long-term political, economic, and social changes are these 16 hydrodynamic modes. These democratic principles or Goldstone bosons have dominated the word history since the dawn of the humanity, and these same 16 global mega-trends of the Goldstone bosons will continue to dominate the world political and economic dynamics in the future, and eventually push the human society towards the equilibrium state of the permanent world peace. The hydrodynamic mode approach not only answers the question what drives social changes, but also becomes a powerful new tool to study world history, social science, and futurology (or scientific astrology). This paper further strengthens the argument that social science is a subfield of quantum physics just like the condensed matter physics and chemistry. The arrow-of-time phenomena in the human society and the natural world share the same identical fundamental causes of quantum indeterminacy and human choices.
