1 Introduction

Logic is a disparate topic, occurring in almost any field of human activity without appearing to have much character of its own. Traditionally it was associated largely with methods of reasoning and regarded as encapsulated in the principles of syllogistic logic. It was the concern mostly of philosophers and developed in the context of rather general questions. During the second half of the nineteenth century there was especial concern with connections with psychology. For example, some authors maintained that psychology is a descriptive theory concerned with how we think, while logic is a normative discipline about how we ought to think (see [74] for the case of Mill).

Mathematics began to play a signi?cant role in logic with Boole's work around 1850 on Boolean algebra. From the technical point of view his work increased the scope of reasoning; and his contemporary De Morgan and successors Peirce and Schröder moved still further beyond the con?nes of syllogistic logic when they developed a theory of relations in their algebraic logic. Otherwise, however, the generality of concern remained; for example, Boole saw his own logic as concerned with the workings of the mind.

A different tradition was instituted around 1880 with the mathematical logic of Frege and Peano, and its development by Russell and Whitehead. Not only is the logic itself rather different in form; the motivations lie in specific questions in the foundations of mathematics, in contrast to the general concerns indicated above for otherlogicians.

1 Honor to Green

Among the centenaries of mathematicians and scientists celebrated in 1993, perhaps the most remarkable was the bicentenary of the birth of a professional miller and part-time mathematician, one George Green (1793–1841) of Sneinton, then near Nottingham. Among other achievements, he was the creator of theorems and functions now named after him which make him a principal contributor to potential theory and to its applications in mechanics and mathematical physics.

During the week corresponding to that of his birth (which occurred on 14 July) various events took place. A three-day conference was held at the University of Nottingham, mainly on the use of his work in modern mathematics and physics. It included a visit to the mill at Sneinton which had been restored and opened as a science center in 1985. The next day a stained glass window was dedicated at the Gonville and Caius College, Cambridge, where he was resident from 1833 to 1837 as an extremely mature student, and (only) for the winter of 1839–1840 as a Fellow. Finally, on Friday 16 July a meeting was held at the Royal Society of London on his life and work and the modern importance of the latter. It was followed by a quite exceptional event: the unveiling of a plaque in his memory in the floor of the nave of Westminster Abbey, close to the tomb of Isaac Newton and to the plaques for his first publicist Lord Kelvin, Michael Faraday and Clerk Maxwell.