Part 2/11:
Feynman begins by challenging the audience to rethink seemingly harmless rituals, such as brushing teeth. Historically regarded as essential for dental health, he raises doubts about the validity of this belief: "What evidence do we really have?" By drawing comparisons to the archaic belief in witchcraft, he prompts a powerful introspection on how contemporary society, like those in the Middle Ages, may also hold onto rituals devoid of solid evidence.
He encourages listeners to adopt a perspective reminiscent of someone witnessing Earth for the first time, particularly where dark and light intersect—the "edge of the Earth." This imaginative exercise suggests that human beings often engage in repetitive actions without fully understanding their significance or the consequences.