Einstein took on two major roles: scientist and activist. He campaigned for peace in Germany during World War I and, later, supported Zionism—the return of Jews to the “Holy Land”—as a way for Jewish peoples to escape antisemitism. Renouncing his anti-war views, Einstein campaigned secretly to get the US government to develop an atomic bomb before Germany could do so. After World War II, Einstein argued for nuclear disarmament. In 1952, he was offered the presidency of Israel, but he turned it down, preferring to continue his scientific work, saying, “[P]olitics is for the present, but an equation is something for eternity” (193).

Galileo is considered the first modern scientist. He believed people could learn how the world works by observing it carefully. His support for the Copernican theory that the Earth revolves around the sun was deemed heretical by the Catholic Church, and the pope forbade Galileo from espousing it. Galileo finally convinced a later pope to let him write an even-handed book about the Copernican and Earth-centered theories; this book, Dialogue Concerning the Two Chief World Systems, was published in 1632 to great acclaim and helped convince the world that the sun, and not the Earth, was at the center of the solar system (195).