Johann Heinrich Lambert (Jean-Henri Lambert in French) was a Swiss polymath who made important contributions to the subjects of mathematics, physics (particularly optics), philosophy, astronomy and map projections. Edward Tufte calls him an...

Immanuel Kant was a German philosopher who is widely considered to be a central figure of modern philosophy. He argued that fundamental concepts structure human experience, and that reason is the source of morality. His thought continues to...

Paul-Henri Thiry, Baron d'Holbach was a French-German author, philosopher, encyclopedist and a prominent figure in the French Enlightenment. He was born Paul Heinrich Dietrich in Edesheim, near Landau in the Rhenish Palatinate, but lived an...

Adam Ferguson was a Scottish philosopher, social scientist and historian of the Scottish Enlightenment. He is sometimes called "the father of modern sociology." Ferguson's Essay on the History of Civil Society (1767) drew on classical autho...

Charles Bonnet, Swiss naturalist and philosophical writer. In 1760 he described a condition now called Charles Bonnet Syndrome, in which vivid, complex visual hallucinations (fictive visual percepts) occur in psychologically normal people....

Claude Adrien Helvétius was a French philosopher and littérateur. In 1758, Helvétius published his philosophical magnum opus, a work called De l'esprit (On Mind). Its atheistic, utilitarian and egalitarian doctrines raised a public outcry a...

As a brilliant, undisciplined, and unconventional thinker, Jean-Jacques Rousseau spent most of his life being driven by controversy back and forth between Paris and his native Geneva. Rousseau first attracted wide-spread attention with his...

David Hume was a Scottish philosopher, historian, economist, and essayist known especially for his philosophical empiricism and scepticism. He was one of the most important figures in the Scottish Enlightenment, and in the history of Wester...

Julien Offroy de La Mettrie, French physician, atheist, mechanist and materialist; an infamous specimen of the Enlightenment. La Mettrie's Man a Machine (L'Homme Machine, 1748) is his main and most infamous work. He wrote his Man a Machine...

Pierre-Louis Moreau de Maupertuis was a French mathematician, philosopher and man of letters. He became the Director of the Académie des Sciences, and the first President of the Berlin Academy of Science, at the invitation of Frederick the...

Francis Hutcheson was a philosopher born in Ireland to a family of Scottish Presbyterians who became one of the founding fathers of the Scottish Enlightenment. Hutcheson was an important influence on the works of several significant Enlight...

François-Marie Arouet, better known by the pen name Voltaire, was a French Enlightenment writer and philosopher famous for his wit and for his advocacy of civil liberties, including freedom of religion and free trade. Voltaire was a proli...

Willem Jacob 's Gravesande was a Dutch philosopher and mathematician. His chief contribution to physics involved an experiment in which brass balls were dropped with varying velocity onto a soft clay surface. His results were that a ball wi...

Emanuel Swedenborg was a Swedish scientist, philosopher, Christian mystic and theologian. Swedenborg had a prolific career as an inventor and scientist. In 1741 at the age of fifty-three he entered into a spiritual phase in which he eventua...

George Berkeley was one of the three most famous (Locke and Hume) eighteenth century British Empiricists. He is best known for his motto, esse is percipi, to be is to be perceived. He was an idealist: everything that exists is either a...