 One ‘easy’ case where OR1 can be straightforwardly applied is when a theory, \(T\), postulates entities which are explanatorily idle. Excising these entities from \(T\) produces a second theory, \(T^*\), which has the same theoretical virtues as \(T\) but a smaller set of ontological commitments. Hence, according to OR1, it is rational to pick \(T^*\) over \(T\). (As previously noted, terminology such as ‘pick’ and ‘prefer’ is crucially ambiguous between epistemic and methodological versions of Occam’s Razor. For the purposes of defining ontological parsimony, it is not necessary to resolve this ambiguity.) However, such cases are presumably rare, and this points to a more general worry concerning the narrowness of application of OR1. First, how often does it actually happen that we have two (or more) competing theories for which ‘other things are equal’? As biologist Kent Holsinger remarks,