As always, it was delightful and confusing to hear from him. “Dave, listen.” He sounded breathless and exigent, and as always the conversation began in the middle. “What’s the largest mammal you’ve never heard of?” I thought about that for a moment. Norwegian Leo is a mechanical engineer by profession, a precise and intelligent man of far-ranging but focused enthusiasms, a man who writes letters containing better English prose than most of what I read in magazines, who loves crisp language and German cameras and improbable living creatures, who is accustomed by disposition as well as by training to checking his facts down to the fourth decimal place. I knew he had said exactly what he intended to say. I thought passingly about several largish animals of the mammalian persuasion. And then I couldn’t help thinking also about St. Anselm, an eleventh-century Italian monk with a smart-aleck streak who made a name for himself in the history of philosophy by inventing an infuriatingly clever piece of logic called the ontological argument.