 This is the concept: being an object \(y\) which precedes the number of the concept: member of the predecessor series ending in \(y\). Let us abbreviate the \(\lambda\)-expression that denotes this concept as ‘\(Q\)’. Our strategy is to instantiate the variable \(F\) in the Principle of Mathematical Induction to \(Q\). The result is therefore something that has been proved and that we therefore know to be true: 