Augustus De Morgan and the Logic of Relations

The middle years of the nineteenth century saw two crucial developments in the history of modern logic: George Boole's algebraic treatment of logic and Augustus De Morgan's formulation of the logic of relations. The former episode has been studied extensively; the latter, hardly at all. This is a pity, for the most central feature of modern logic may well be its ability to handle relational inferences. De Morgan was the first person to work out an extensive logic of relations, and the purpo...