 In this situation, a suggestion would be to simply stipulate that constancy amounts to Ext + Isom. This would be a Carnapian explication of constancy. Quantifiers with this combination of properties seem certain to mean the same on all universes. On the other hand, Ext but non-Isom quantifiers like three\(^{\textit{student}}\) or some professor’s would not have the same meaning across different domains, which as we saw accords with one intuition. Furthermore, the few natural non-Ext quantifiers we have encountered are all definable from Ext + Isom  quantifiers.[31]