 The expression “sortal” reappeared on the philosophical stage in the 1950s and 1960s in lectures and in the written work of Strawson (1959), Quine (1960), Geach (1962), and Wiggins (1967) and variations on the concept entered the mainstream philosophical vocabulary. Because philosophers lecture and circulate manuscripts with their ideas for years—sometimes decades—before publication, the dates of the main publications of the protagonists concerning sortals do not necessarily reflect the historical priorities and influences. The most accurate simple summary is that the ideas of Geach, Strawson and Quine co-evolved and that Wiggins’ writings built on a foundation laid by those predecessors.