 Inspired mainly by Peirce’s work, Schröder examined the algebra of logic for binary relations in Vol. III of his Vorlesungen über die Algebra der Logik. As Tarski once noted, Peirce’s work was continued and extended in a very thorough and systematic way by Schröder. One item of particular fascination for him was this: given an equation \(E(x, y, z, \ldots) = 0\) in this algebra, find the general solution for one of the relation symbols, say for \(x\), in terms of the other relation symbols. He managed, given a particular solution \(x = x0\), to find a remarkable term \(S(t, y, z, \ldots)\) with the following properties: (1) \(x = S(t, y, z, \ldots)\) yields a solution to \(E = 0\) for any choice of relation \(t\), and (2) every solution \(x\) of \(E = 0\) can be obtained in this manner by choosing a suitable \(t\). Peirce was not impressed by Schröder’s preoccupation with the problem of solving equations, and pointed out that Schröder’s parametric solution was a bit of a hoax—the expressive power of the algebra of logic for relations was so strong that by evaluating the term \(S(t, y, z, \ldots)\) one essentially carried out the steps to check if \(E(t, y, z, \ldots) = 0\); if the answer was yes then \(S(t, y, z, \ldots)\) returned the value \(t\), otherwise it would return the value \(x0\).