The terms “Enlightenment” and “liberalism” are often used synonymously. Even among scholars, they seem to designate a broadly similar historical phenomenon – the social, economic, and political philosophy which emerged in the long eighteenth century, and which became the basis of modern democratic societies, including a generally accepted amalgam of ideas – the reliance on rational argumentation, religious toleration, free market economics, an emphasis on public education, broad political suffrage, and eventually, though this has proven more difficult to implement, racial and gender equality. It is often taken for granted that sometime in the transition from the eighteenth to the nineteenth century the social and political program of the Enlightenment somehow transformed and became liberalism (the term itself emerged in the early nineteenth century). Of course, at the same time, many historians emphasize how following the revolutionary era, a reaction against the more radical aspects of the Enlightenment set in, and early liberalism, if indeed we accept the term, mirrored a diluted and moderate, at times almost reactionary, version of the earlier, more optimistic, ideals of the pre-revolutionary era. It was against this more conservative background that early liberalism had to strive to implement enlightened goals. For this reason, those with more radical political programs often found themselves in the nineteenth century attracted to various socialist political philosophies. Liberalism, therefore, had to fight a twofront battle, both from left and right. In each country it faced different challenges. Historical developments in France or Britain, to note two significant examples, often diverged. Yet this overall trajectory was broadly similar in most Western European countries, as well as in the United States.

All of this is, of course, a generalization painted with a very broad brush. Some historians would even question whether the term “liberalism” has any historical validity, or whether viewing it as a continuation of the Enlightenment is justified. In what follows, however, these terminological generalizations will be tacitly accepted. The term “liberalism,” in particular, has become so common, that no discussion of modern political thought can dispense with using it. Beyond this general terminology, however, the present study, rather than discuss the transition from the eighteenth-century Enlightenment to nineteenth-century liberalism from a broad perspective, concentrates on how this process can be viewed through one case study – the intellectual biography of one prominent British liberal, the historian Thomas Babington Macaulay.