F. A. Hayek
Written in 1973 for the Italian Enciclopedia del Novicento where the article appeared in an Italian translation.
Reprinted as Chapter Nine of Hayek, F. A., New Studies in Philosophy, Politics, Economics and the History of Ideas, Routledge & Keagan Paul, London and Henley, 1982 , pp. 119-151 ORDER THIS BOOK
The term is now used with a variety of meanings which have little in common beyond describing an openness to new ideas, including some which are directly opposed to those which are originally designated by it during the nineteenth and the earlier parts of the twentieth centuries. What will alone be considered here is that broad stream of political ideals which during that period under the name of liberalism operated as one of the most influential intellectual forces guiding developments in western and central Europe. This movement derives, however, from two distinct sources, and the two traditions to which they gave rise, though generally mixed to various degrees, coexisted only in an uneasy partnership and must be clearly distinguished if the development of the liberal movement is to be understood.
The one tradition, much older than the name 'liberalism', traces back to classical antiquity and took its modern form during the late seventeenth and the eighteenth centuries as the political doctrines of the English Whigs. It provided the model of political institutions which most of the European nineteenth‑century liberalism followed. It was the individual liberty which a 'government under the law' had secured to the citizens of Great Britain which inspired the movement for liberty in the countries of the Continent in which absolutism had destroyed most of the medieval liberties which had been largely preserved in Britain. These institutions were, however, interpreted on the Continent in the light of a philosophical tradition very different from the evolutionary conceptions predominant in  Britain, namely of it rationalist or constructivistic view which demanded a deliberate reconstruction of the whole of society in accordance with principles of reason. This approach derived from the new rationalist philosophy developed above all by René Descartes (but also by Thomas Hobbes in Britain) and gained its greatest influence in the eighteenth century through the philosophers of the French Enlightenment. Voltaire and J.‑J. Rousseau were the two most influential figures of the intellectual movement that culminated in the French Revolution and from which the Continental or constructivistic type of liberalism derives. The core of this movement, unlike the British tradition, was not so much a definite political doctrine as a general mental attitude, a demand for an emancipation from all prejudice and all beliefs which could not be rationally justified, and for an escape from the authority of 'priests and kings'. Its best expression is probably B. de Spinoza's statement that 'he is a free man who lives according to the dictates of reason alone'.
These two strands of thought which provided the chief ingredients of what in the nineteenth century came to be called liberalism were on a few essential postulates, such as freedom of thought, of speech, and of the press, in sufficient agreement to create a common opposition to conservative and authoritarian views and therefore to appear as part of a common movement. Most of liberalism's adherents would also profess a belief in individual freedom of action and in some sort of equality of all men, but closer examination shows that this agreement was in part only verbal since the key terms 'freedom' and 'equality' were used with somewhat different meanings. While to the older British tradition the freedom of the individual in the sense of a protection by law against all arbitrary coercion was the chief value, in the Continental tradition the demand for the self‑determination of each group concerning its form of government occupied the highest place. This led to an early association and almost identification of the Continental movement with the movement for democracy, which is concerned with a different problem from that which was the chief concern of the liberal tradition of the British type.
During the period of their formation these ideas, which in the nineteenth century came to be known as liberalism, were not yet described by that name. The adjective 'liberal' gradually assumed its political connotation during the later part of the eighteenth century when it was used in such occasional phrases as when Adam Smith wrote of 'the liberal plan of equality, liberty, and justice'. As the  name of a political movement liberalism appears, however, only at the beginning of the next century, first when in 1812 it was used by the Spanish party of Liberales, and a little later when it was adopted as a party name in France. In Britain it came to be so used only after the Whigs and the Radicals joined in a single party which from the early 1840s came to be known as the Liberal Party. Since the Radicals were inspired largely by what we have described as the Continental tradition, even the English Liberal Party at the time of its greatest influence was based on a fusion of the two traditions mentioned.
In view of these facts it would be misleading to claim the term 'liberal' exclusively for either of the two distinct traditions. They have occasionally been referred to as the 'English', 'classical' or 'evolutionary', and as the 'Continental' or 'constructivistic' types respectively. In the following historical survey both types will be considered, but as only the first has developed a definite political doctrine, the later systematic exposition will have to concentrate on it.
It should be mentioned here that the USA never developed a liberal movement comparable to that which affected most of Europe during the nineteenth century, competing in Europe with the younger movements of nationalism and socialism and reaching the height of its influence in the 1870s and thereafter slowly declining but still determining the climate of public life until 1914. The reason for the absence of a similar movement in the USA is mainly that the chief aspirations of European liberalism were largely embodied in the institutions of the United States since their foundation, and partly that the development of political parties there was unfavourable to the growth of parties based on ideologies. Indeed, what in Europe is or used to be called 'liberal' is in the USA today with some justification called 'conservative'; while in recent times the term 'liberal' has been used there to describe what in Europe would be called socialism. But of Europe it is equally true that none of the political parties which use the designation 'liberal' now adhere to the liberal principles of the nineteenth century.