A professor of psychology at Harvard, Steven Pinker is an experimental psychologist and a writer on language, mind, and human nature. His most recent book is The Better Angels of Our Nature: Why Violence Has Declined, a title that all but begs some wiseguy interviewer to take a swing at him. He famously defended Larry Summers’ sexist remark about the gender gap in math and science, ensuring that pretty much everybody else would take a swing at him. He does not lack nerve.

• PERSON: Lewis Fry Richardson
• PLACE: MIT’s historic Building 20
• THING: A chunk of the Berlin Wall