The implication of an “actual” form of this property spawned controversy surrounding the Barcan formula. An essay titled for this property discusses the “spatio-temporal connotations” of the word “Pegasus” in a sentence by a philosopher dubbed “McX” and features an argument named after “Plato’s beard” for dulling Occam’s razor by ascribing it too often. (-5[1])The Quine–Putnam indispensability thesis supports a stance sometimes referred to as Platonism that assigns this property to mathematical objects. (10[2]-5[1])The logical operator (10[1])written as a backward capital E (10[3])quantifies (-5[1])this (10[1])property, (10[2])which is the subject of study in ontology. (10[1])For 10 points, name this property given to matter by materialists and to numbers by mathematical realists. ■END■ (10[3])