Without it, humans never would have changed the environment so much, building dams and clearing forests and more recently drilling for oil that we can turn into fertilizer. Many people made the choice for agriculture independently, but does that mean it was the right choice? Maybe so, and maybe not, but regardless, we can't unmake that choice. And that's one of the reasons I think it's so important to study history. History reminds us that revolutions are not events so much as they're processes. That for tens of thousands of years, people have been making decisions that irrevocably shaped the world that we live in today. Just as today we're making subtle, irrevocable decisions that people of the future will remember as revolutions.