In the stricter sense, the Enlightenment is an intellectual movement from the 18th century, furthermore, it is the intellectual movement of that century. When we think about it, we refer to a number of philosophers, or maybe even better, philosophes, mainly French, but also British and German. Just providing a few names will suffice: Montesquieu, Rosseau, Voltaire, the encyclopedist (D=Alembert, Diderot); from the British side Locke and Hume are probably the most relevant; and from the German side Lessing and Kant. This short list is not intended to be exhaustive of course, it is basically ad demonstrandum. Apart from the fact that there are many other Enlightenment philosophers in these countries as well as in others, there were many other thinkers who are not considered philosophers in the strict sense but whose work is strongly related in one way or another to the work of those listed here.
Nevertheless, what do these philosophers have in common?, what novel element does this self-appointed Enlightenment movement have? Kant defined it this way: The Enlightenment is man's emergence from his self-imposed incapacity. Incapacity means the impossibility to make use of intelligence without the guidance of others. This incapacity is self-impossed because its origin is not due to the lack of intelligence, but to the lack of decision and courage to make use of it without the assistance of other people. (Sapere aude! (Dare to know! (Have courage to make use of your own understanding! This is the motto of the Enlightenment.
This clear definition is truthful in the sense that Enlightenment thinkers had a group feeling and shared a programme, as Kant clearly put it, they had a first commandment of freedom of thought, intellectual freedom, and the rupture with limitations and mental inertias. It would be an error to think, though, that nobody tried to fight against mental dependence until the 18th century. As a matter of fact, Enlightenment thinkers were heirs of the so-called Scientific Revolution of the previous century whose main actors (Copernicus, Tycho Brahe, Kepler, Galileo, Descartes, Leibniz and Newton) were known for their work in demolishing the cosmology inherited, and for building new and revolutionary physical science that set the basis for modern science confronted by strong social resistance: It is well known that Copernicus was afraid of publishing his Heliocentric Theory, and that Kepler, and specially Galileo, were persecuted by the Catholic Church.
The issue is that if the Scientific Revolution was the origin of modern physical sciences, the Enlightenment had the same effect over social sciences a century later. Most probably, the birth of physical sciences between the 16th and 17th century is due to the three phenomena: the improvement of geographical knowledge due to the discoveries that started in the 15th century; the invention of the printing press in that same century, which allowed for a fast and economical dissemination of knowledge; and the invention of experimental tools, especially optic, developed from medieval discoveries like crystal lenses, spring clocks, compasses, etc. The birth of social sciences in the 18th century has a strong relation with these same phenomena (the influence of physical sciences over social sciences has been permanent since then), but it has an even stronger link with other social and political processes, namely the Protestant Reformation on one side, and the English Revolution and Dutch Revolt on the other. Both political revolutions allowed for scientific and technological developments, and in a concomitant way, for the Industrial Revolution.
The English and Dutch revolutions put an end to absolute monarchies, and the English revolution in particular gave way to a parliamentary political system and a constitutional monarchy. It is not by chance that these were followed by a strong economic growth that promoted strong competition and, in England, the Industrial Revolution. In parallel to this, another big political revolution occurred, the Atlantic Revolutions that took place between the end of the 18th century and the beginning of the 19th century, including the independence of the United States of America, the French Revolution and the Latin American Wars of Independence. This huge revolution across the Atlantic, which was inspired by the English Revolution but that surpassed it in many ways, produced an intense economic development in both North America and Europe. It is worth noting that neither the Dutch Revolt in the17th Century, nor the Latin American Wars of Independence in the 19th Century were complete, which explains the relative truncated economic record both produced.
Both the English Revolution and Atlantic Revolution are strongly associated to the intellectual movement of the Enlightenment, and are the source of the first big discontinuity of the current growth process. But despite the perturbations they caused, I insist in the idea that they ultimately gave way to an unprecedented economic growth.
The second big discontinuity in growth occurred later in the 20th century, which is the Social Democracy or Proletarian Revolution. The Atlantic and English revolutions (which can be included among the liberal revolutions ) allowed the medium class to access political power, but had excluded the working class or proletarians by restricting their access to vote. With development and industrialization, this social group became very numerous and reclaimed their participation in the political process through universal suffrage. Universal suffrage further extended to most developed countries starting in the 19th Century and beyond the First World War. With universal suffrage (democracy), labour and socialist parties came to power and generalized the social democracy model based on Assisting or Welfare State, and on the implementation of ruling mechanisms that fostered the working class to play an increasing role on collective decisions: unions, parity committees, etc. The triumph of communism in Russia on one side facilitated the Social Democracy Revolution, but on the other, it was a matter of worry for the medium class and contributed to a very significant phenomenon of this period: the triumph of fascism (Nazism, Falangism, Salazarism, etc.) in the south and east of Europe, in countries where for one reason or another, the liberal parliamentary system was not very well established. It is in the confrontation between fascists and democrats that the origin of the Second World War lies. With the triumph of the later, the social democracy system became generalized among the developed countries, while the Communist Bloc –which was an aberration from the point of view of the Marxist terms proclaimed by the Communist Movement- became stalled economically and socially.
The success of the social democracy revolution was accompanied by a renewed process of economic growth that was even faster than the one on the 19th century. After a century of intense industrialization (19th century), the growth on the second half of the 20th century witnessed the first steps of the inverse process: deindustrialization of advanced economies, where the increase of salaries made production costs rise in favour if semi-developed countries, and favoured the development of a service-based economy or tertiarization of the economy. This phenomenon, together with the universal suffrage, and the dissemination of contraceptive techniques favoured another radical social change: the feminine revolution, with the massive incorporation of women to the labour market that produced deep consequences in the family structure, and thus, in the basic constitution of social organization. All this was associated to an increasing urbanization in both developed and non-developed countries. A very powerful motor of progress has been the scientific advance, which has also suffered and impressive growth since the Industrial Revolution, and which is stimulated by the tertiarization of the economy, as well as by the increase of investment in research and education, mainly in developed countries.
Obviously, one of the main consequences of the spectacular socioeconomic success of the recent centuries, is the also spectacular improvement of the conditions of life (from the basic conditions -food, housing, clothing, etc.- to the not so basic -culture, health, life expectancy, etc.-) in Europe and the rest of temperate regions of the World. One to the results from this improvement in life conditions and life expectancy (the average lifespan of man has more than doubled on average in just a century; in Europe from 46 to 78 years, it did not double because it was already relatively high in the 1900s) has been the increase in population growth. In round numbers, the World’s population has had a six-fold increase between 1800 and 2000, and is still growing at a dramatic rate nowadays. Nevertheless, in Europe population grew moderately during the 20th century and is virtually stagnant in the present. The current European level of life acts like a magnet for populations from the Third World, so Europe together with the United States of America, are a land of promise for a large part of the World’s population.
We should not forget, though, that the beautiful story of European development has a dark side too. Europe, the cradle of democracy and coexistence, suffered terrible blows in parallel to the extension of rights and freedom. It has often been said that the world wars that occurred during the 20th century were European civil wars in origin, and this is partially correct. Both wars left behind a very weak Europe, so two powerful reasons appeared in favour of a European Union: the wish to finalize all fraternal wars on one side, and the gaining political and economical strength on the other. A double miracle, economical and political, indeed occurred: Europe managed to go through a spectacular recovery following the Second World War, and this recovery was strongly linked to a progressive economic and political integration. In the present, Europe together with the United States of America, are the two main multicultural unions in the World. And this is a remote consequence of the Enlightenment period, whose spirit lies in the main pillars building Europe.