The history of Protestant Dissent in the British Isles from the Reformation to the early twenty-first century has generated a substantial and growing body of research. Each denomination has an important archive, at least one historical journal, and a long-standing historiographical tradition. Dissent, or Nonconformity as it was increasingly described in the nineteenth century, was associated with issues that were of essential concern to the population as a whole; at various times they have included freedom of conscience, pacifism, free trade, entrepreneurship, education, and social improvement. Its long-term theological, political, and social presence has been fully recognised by historians, notably in the magisterial three-volume survey by Michael Watts. Our knowledge of Dissent has been enhanced through regional and local studies, congregational histories, and biographies. Yet Dissent was (and is) a multi-faceted phenomenon and many of its aspects are still in need of further exploration. One such aspect is the feature of English Nonconformity which, in the second half of the eighteenth century, came to be known as ‘Rational Dissent’. Although constituting a fairly small minority within English society, Rational Dissenters exerted an influence far beyond their numbers. Much of the evidence for this statement lies in the importance attributed to its identity by friend and foe alike amongst its contemporaries between 1770 and 1800.

Most previous studies of Rational Dissent have focused upon its political characteristics, notably its libertarianism, rather than the theology that underpinned its nature and identity. This book adopts a different approach by giving priority to its theological doctrines, and by emphasising that without an understanding of those doctrines its political aspects cannot fully be appreciated. Central to this argument is that the last thirty years of the eighteenth century were of particular significance for the emergence of the nature and identity of Rational Dissent. While in the two decades before 1770 only a small number of members of the Established Church or Protestant Dissent would have used the term Rational Dissent, by 1800 it had achieved widespread recognition and a distinctive identity. The subject of identity has been very important to late twentieth- and twenty-first-century historians, amongst them many specialists in eighteenth-century history.