“If I were to add two more determinants to keep in mind, they would be 4) the pace of innovation and technological development to solve problems and make improvements and 5) acts of nature, most importantly droughts, floods, and diseases. That is because innovation and technological advances can solve most problems and further evolution, and acts of nature such as droughts, floods, and diseases have had enormous impacts throughout history. These are the five most important forces, which I call the “Big Five,” so when they are moving in the same direction—toward improving or toward worsening—most everything else follows.”