 But the technical results alone did not settle the matter in favor of first-order logic. As Schiemer &amp; Reck point out (2013), well into the 1930s, even after the principal metalogical results had been achieved, logicians such as Gödel, Carnap, Tarski, Church, and Hilbert &amp; Bernays continued to use higher-order systems (generally in some version of the simple theory of types). In other words, even after the metalogical results there was a choice to be made, and the choice in favor of first-order logic was not inevitable. After all, the metalogical results can be taken to show a severe limitation of first-order logic: that it is not capable of specifying a unique model even for the natural numbers. Hilbert in 1917/18 had treated first-order logic as a mere stepping-stone, and the metalogical results can be taken to confirm the wisdom of his approach: If you want categoricity, then you are forced to move to a higher-order system.