While sentences of any order can be Ramseyfied, many technical discussions (e.g., the overview by van Benthem 1978) treat the special case in which axioms and dictionary are of first order and the Ramsey sentence is of second order. In this case, the class of models of the observational first-order implications of \(TC\) can be a proper superset of the class of models of \({TC}^R\). This has been known at least since 1941 as the difference between elementary and pseudoelementary classes (Hodges 1993, 207, 260) and is regularly rediscovered in philosophy (see Demopoulos 2011, 179). It entails that \({TC}^R\) can be false in a structure even though all the first order implications of \(TC\) are true. Specifically, \(TC\) may only have tautological observational implications even though the Ramsey sentence is not logically true; this situation is one version of the distinction between syntactic and semantic conservativeness known from definition theory (Gupta 2015, §2.3; Przełęcki 1969, 52–53).