 What should we make of this non-standard conception of ontological commitment in terms of truth-making: that to be is to be a truth-maker? Cameron (2008c) has proposed that this conception should replace the standard one that to be is to be the value of a variable. But this threatens to cut off the branch the advocates of truth-maker theory are sitting on: if they disavow that existential quantification is ontologically committing then they will be left without a means of determining the ontological commitments of truth-maker theory itself, i.e., the theory that gives the inventory, using existential quantification, of what makes all the truths true (Schaffer 2010: 16–7).