Few scientists of the past half-century are as popular as Carl Sagan. As an astronomer and planetary scientist, he’s perhaps best known for his research on extraterrestrial life. He also penned a number of popular science books, such as 1994’s “Pale Blue Dot”; co-wrote and narrated the hit television series “Cosmos”; and wrote the 1985 sci-fi novel “Contact.” Sagan was a passionate advocate of skeptical inquiry and the scientific method, but argued that critical thinking must go hand-in-hand with kindness. While we may strongly disagree with people who do not share our beliefs, we must not fall into the trap of self-righteousness, because none of us is perfect, and “none of us comes fully equipped.”