 In order to temper the modest commitment just mentioned, all derivations are constructed within a free logic, so that all existential commitments other than those incurred by the rules themselves would have to be made  explicit.[46]  All of the existential commitments that the constructive logicist incurs in this way will be incurred, anyway, by the HP-er who advocates Hume’s Principle in its unrestricted form. Recall that the HP-er is committed, not only to the number of all natural numbers, but also to the number of all self-identical things. 