Edge.org is a wonderful online version of “The Reality Club” and had a yearly tradition of inviting diverse thinkers to respond to stimulating questions over the 20 years from 1998 until the final question in 2018. The responses were turned into books and published on the Edge website. The 2017 question was “What scientific term or concept ought to be more widely known?” Steve Omohundro’s response was this essay on the topic of “Costly Signalling”: