The 2001 discovery of the seven million-year-old Sahelanthropus, the first known upright ape-like creatures, was yet more proof of humanity’s place among the great apes. And yet Mike Pence, then a representative and now US vice president, argues for the opposite conclusion.For him, our ideas about our ancestors have changed, proving once more that evolution was a theory, and therefore we should be free to teach other theories alongside evolution in our classrooms. How to respond? The usual answer is that we should teach students the meaning of the word “theory” as used in science – that is, a hypothesis...