 All \(H\) are \(S\) so long as there are no \(\neg S\) that share a location with something that is not a \(\neg H\). That is, there will be pervasion given co-locatedness so long as what the \(S\) is, according to the definition, is not something that in serving as the counterpositive of an absence—specifically a counterpositive having shared locations, a universal, a class character, a repeatable property and not a particular instance (firehood as opposed to, say, kitchen fire)—does not share any location that does not also house a \(\neg H\). Goekoop (1967: 111) has a nice paraphrase that makes the point a little clearer: “There is a pervasion of \(H\) by \(S\) if and only if \(H\) has a common locus with \(S\) in such a way that \(S\) is none of the things that qua class are completely absent from some locus of \(H\).”