One of the most prominent intellectuals of the 20th century, Bertrand Russell was a polymath who believed that ideas could change the world. In addition to being a mathematician, philosopher, and preeminent logician, he was also a humanist and a pacifist whose ideas at times proved controversial — his pacifism during World War I, for instance, earned him a six-month spell in prison. In a December 1951 issue of “The New York Times Magazine,” Russell published his “ten commandments” of critical thinking, including the one featured here. He reminds us that although our thoughts and ideas may not be accepted at first, every great thought and idea once had to face its share of skepticism and naysayers.