PHILADELPHIA — One morning in February 2012, Prof. David Skeel received an email from a stranger named Patrick Arsenault. The message contained a thumbnail photo of the equation for calculating kinetic energy, and the signature line identified the writer as a postdoctoral fellow at the medical school of the University of Pennsylvania. All of which gave Professor Skeel cause for curiosity.

The previous night, he had moderated a public conversation with John C. Lennox, an Oxford mathematician and committed Christian. The event was meant to show that faith and reason could be reconciled, not exactly an easy sell on campuses these days, and for his part, Professor Skeel was less a neutral facilitator than a partisan.