Human evolution is often told as a tidy story of adaptation, yet some of our most familiar body parts still defy straightforward explanation. From the jut of the human chin to the curve of the outer ...

The Bible’s lex talionis – “Eye for eye, tooth for tooth, hand for hand, foot for foot” (Exodus 21:24-27) – has captured the human imagination for millennia. This idea of fairness has been a model for ...

Many of the challenges we address here were evident to the pioneers of medical decision analysis of the 1950s 7 and to scholars in subsequent decades 8-11 who conducted careful and creative studies of ...

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their ...