How does the author support his claim that there are tipping points for social problems?

One of the main themes in the book is the idea that every little action matters. The author points out the way in which the actions we take influence our lives and those around us. The author mentions a few key people in history who influenced the way we live today through their actions and their ideas. They were either Patient Zero and brought into the world a pandemic that still affects us today or they were great thinkers who influence modern society through their ideas. Either way, the author shows the important of every little action and highlights the idea that even though we may believe that our actions are unimportant, they may be in fact more important that we could ever think of.