 Another question that receives such a reformulation is that of the existence of abstract entities, which, according to Church, are “postulated” as ontological commitments of a true sentence or theory that has been developed in accordance with the strictures of the logistic method. The basic idea is that theory \(T\) is ontologically committed to entities of kind \(K\) if the truth of \(T\) implies that there are \(K\)s (1958a). Moreover, as Church clarified later, “theory” was intended to encompass not only formal theories but also