The Age of Enlightenment and Sciences
While the Enlightenment cannot be pigeonholed into a specific doctrine or set of dogmas, science came to play a leading role in Enlightenment discourse and thought. Many Enlightenment writers and thinkers had backgrounds in the sciences and associated scientific advancement with the overthrow of religion and traditional authority in favor of the development of free speech and thought. Broadly speaking, Enlightenment science greatly valued empiricism and rational thought and was embedded with the Enlightenment ideal of advancement and progress. Similar rules were applied to social sciences. However, as with most Enlightenment views, the benefits of science were not seen universally.
Astronomy
Building on the body of work forwarded by Copernicus, Kepler and Newton, 18th-century astronomers refined telescopes, produced star catalogs, and worked towards explaining the motions of heavenly bodies and the consequences of universal gravitation. Among the prominent astronomers of the age was Edmund Halley. In 1705, Halley correctly linked historical descriptions of particularly bright comets to the reappearance of just one (later named Halley’s Comet), based on his computation of the orbits of comets. James Bradley realized that the unexplained motion of stars he had early observed with Samuel Molyneux was caused by the aberration of light. He also came fairly close to the estimation of the speed of light. Observations of Venus in the 18th century became an important step in describing atmospheres, including the work of Mikhail Lomonosov, Johann Hieronymus Schröter, and Alexis Claude de Clairaut. In 1781, amateur astronomer William Herschel was responsible for arguably the most important discovery in 18th-century astronomy. He spotted a new planet that he named Georgium Sidus. The name Uranus, as proposed by Johann Bode, came into widespread usage after Herschel's death. On the theoretical side of astronomy, the English natural philosopher John Michell first proposed the existence of dark stars in 1783.
William Herschel's 40 foot (12 m) telescope. Scanned from Leisure Hour, Nov 2,1867, page 729.
Much astronomical work of the period becomes shadowed by one of the most dramatic scientific discoveries of the 18th century. On March 13, 1781, amateur astronomer William Herschel spotted a new planet with his powerful reflecting telescope. Initially identified as a comet, the celestial body later came to be accepted as a planet. Soon after, the planet was named Georgium Sidus by Herschel and was called Herschelium in France. The name Uranus, as proposed by Johann Bode, came into widespread usage after Herschel's death.
Chemisty
The 18th century witnessed what would eventually be referred to as the chemical revolution or the early modern reformulation of chemistry that culminated in the law of conservation of mass and the oxygen theory of combustion. According to an earlier theory, a substance called phlogiston was released from inflammable materials through burning. The resulting product was termed calx, which was considered a 'dephlogisticated' substance in its 'true' form. The first strong evidence against phlogiston theory came from Joseph Black, Joseph Priestley and Henry Cavendish, who all identified different gases that composed air. However, it was not until Antoine Lavoisier discovered in 1772 that, when burned, sulphur and phosphorus “gain[ed] in weight” that the phlogiston theory began to unravel. Lavoisier subsequently discovered and named oxygen, described its role in animal respiration, and the calcination of metals exposed to air (1774–1778). In 1783, he found that water was a compound of oxygen and hydrogen. Transition to and acceptance of Lavoisier’s new chemistry varied in pace across Europe. Eventually the oxygen-based theory of combustion drowned out the phlogiston theory and in the process created the basis of modern chemistry.
Social Sciences
David Hume and other Scottish Enlightenment thinkers developed a 'science of man,' which was expressed historically in works by authors including James Burnett, Adam Ferguson, John Millar, and William Robertson, all of whom merged a scientific study of how humans behaved in prehistoric and ancient cultures with a strong awareness of the determining forces of modernity. Against philosophical rationalists, Hume held that passion rather than reason governs human behavior and argued against the existence of innate ideas, positing that all human knowledge is ultimately founded solely in experience. He thus argued that genuine knowledge must either be directly traceable to objects perceived in experience, or result from abstract reasoning about relations between ideas which are derived from experience. Modern sociology largely originated from the 'science of man' movement.
Adam Smith published The Wealth of Nations, often considered the first work on modern economics, in 1776. It had an immediate impact on British economic policy that continues into the 21st century. The book was immediately preceded and influenced by Anne-Robert-Jacques Turgot, Baron de Laune drafts of Reflections on the Formation and Distribution of Wealth (Paris, 1766). Smith acknowledged indebtedness and possibly was the original English translator.
Enlightenment-era changes in law also continue to shape legal systems today. Cesare Beccaria, a jurist and one of the great Enlightenment writers, published his masterpiece Of Crimes and Punishments in 1764. Beccaria is recognized as one of the fathers of classical criminal theory. His treatise condemned torture and death penalty and was a founding work in the field of penology (the study of the punishment of crime and prison management). It also promoted criminal justice. Another prominent intellectual was Francesco Mario Pagano, who wrote Saggi Politici (Political Essays, 1783), which argued against torture and capital punishment and advocated more benign penal codes.
Portrait of Cesare Bonesana-Beccaria, author unknown, source: Wikipedia.
Although less widely known to the general public than his fellow English, Scottish, or French philosophers of the era, Beccaria remains one of the greatest thinkers of the Enlightenment era. His theories have continued to play a great role in recent times. Some of the current policies impacted by his theories are truth in sentencing, swift punishment and the abolition of death penalty. While many of his theories are popular, some are still a source of heated controversy, more than two centuries after Beccaria's death.
Scientific Publications
The Age of Enlightenment was also when the first scientific and literary journals were established. The first journal, the Parisian Journal des Sçavans, appeared in 1665. However, it was not until 1682 that periodicals began to be more widely produced. French and Latin were the dominant languages of publication, but there was also a steady demand for material in German and Dutch. There was generally low demand for English publications on the Continent, which was echoed by England's similar lack of desire for French works. Languages commanding less of an international market – such as Danish, Spanish, and Portuguese – found journal success more difficult and more often than not a more international language was used instead. French slowly took over Latin's status as the lingua franca of learned circles. This in turn gave precedence to the publishing industry in Holland, where the vast majority of these French language periodicals were produced. As a source of knowledge derived from science and reason, the journals were an implicit critique of existing notions of universal truth monopolized by monarchies, parliaments, and religious authorities.