This is a reference to the famous quip by Rabi: > The eventual recognition of the muon as a simple "heavy electron", with no role at all in the nuclear interac

This is a reference to the famous quip by Rabi: > The eventual recognition of the muon as a simple "heavy electron", with no role at all in the nuclear interaction, seemed so incongruous and surprising at the time, that Nobel laureate I. I. Rabi famously quipped, "Who ordered that?" https://en.m.wikipedia.org/wiki/Muon https://en.m.wikipedia.org/wiki/Muon