ABSTRACT
7.1. Later developments of Boole’s algebra. Much of the work in Mathematical Logic in the 100 years and more that have gone by after The Laws of Thought has been given to taking out the errors from Boole’s ideas, making some of the parts of his theory stronger, putting his algebra in the form of a system of deductions and, lastly, moving from it towards more general theories in Abstract Algebra, for example towards the theory of those ‘part-ordered’ classes every two elements of which have a greatest lower limit and a smallest higher limit, such part-ordered classes being what are named lattices. We will at this stage say something about one or two of the ways in which Boole’s algebra was changed while he was still living or not long after his death; these changes were made by Jevons, Peirce and Schroeder.
