 Frege’s account is streamlined in other ways as well. He had always considered the analysis of simple identity sentences to be important to his logicism, dating back to the Begriffsschrift (1879), on through his Foundations of Arithmetic (1884) and his “On Sense and Reference” (1892), and even in the appearance of the example “\(2^2 = 2 + 2\)” in the forward to the Basic Laws of Arithmetic. Indeed the analysis of identity sentences is the starting point of his introduction of the theory of sense and reference in 1879, yet Frege does not diverge from his project enough to show how such an identity would be proved. So Whitehead and Russell might well have wanted to include their proof of \(1+1 = 2\) at ∗110·643 as a reminder of the analysis of mathematical equations in PM using the “descriptive functions” of ∗30 and then the account of definite descriptions in ∗14.