 It is also important to point out that Frege used functional application ‘\(f(x)\)’ to form complex names in his language and used these names to represent natural language statements. To see how, note that Frege would use the expression ‘\(f(x)\)’ to denote the value of the function \(f\) for the argument \(x\). Since he also recognized two special objects he called truth-values (The True and The False), he defined a concept to be any function that always maps its arguments to truth-values. For example, whereas ‘\(x^{2} +3\)’ and ‘father-of \(x\)’ signify ordinary functions, the expressions ‘\(x\) is happy’ (which we might represent as ‘\(Hx\)’) and ‘\(x \gt 5\)’ signify concepts. The former signifies a concept which maps any object that is happy to The True and all other objects to The False; the latter signifies a concept that maps any object that is greater than 5 to The True and all other objects to The False. In this way, ordinary language predications like ‘\(b\) is happy’ and ‘4 is greater than 5’, once represented in Frege’s language as ‘\(Hb\)’ and ‘\(4 \gt 5\)’, become names of truth-values.