 For the purposes of understanding Frege’s Theorem, we can think of our 1-place relation terms as denoting, or ranging over, Fregean concepts. Once we do this, we can take the formula ‘\( Hb\)’ to mean that \(b\) falls under the concept being happy. But for the purposes of understanding Frege’s Theorem, it is not necessary to suppose, with Frege, that concepts like being happy are functions from objects to truth values. So, in what follows, one should remember that whereas we can interpret the atomic formula \(Fx\) to mean either that \(x\) exemplifies the 1-place relation (i.e., property) \(F\) or that \(x\) falls under the concept \(F\), Frege would understand such formulas as instances of functional application. Nevertheless, we’ll henceforth call 1-place relations concepts. For all practical purposes then, we may use the symbols \(F\), \(G\), … as variables ranging over concepts and though we sometimes write ‘\(F(x)\)’ instead of ‘\(Fx\)’ for perspicuity in parsing an expression, we should still think of this as a predication.