Van Loo Louis Michel (Musee de Louvre, Paris)

This famous portrait of Denis Diderot (1713-1784) was originally exhibited at a Paris Salon in 1767.

David Hume is considered to be one of the greatest philosophical minds of his time. His contributions to the world of philosophy from a naturalist's perspective are great. His profoundly skeptical philosophy is based on the belief that nothing is in the mind that was not first in the senses. He argues compellingly against many of the claims and conclusions of the rationalist philosophers of his time.

One of his most important arguments involves human knowledge of God. He maintains that we are not justified in claiming any knowledge of this Supreme Being, of the human soul or of absolute moral values. He aims only to examine human nature. In his best philosophical work Treatise on Human Nature, Hume examines the way that human beings perceive the world around them and one another. He established that there are two types of perceptions: impressions and ideas. For Hume, this is the basis of understanding human perception and human nature.

Jean Le Rond d'Alembert was born the illegitimate son of the famous salon hostess Madame Tencin and one of her lovers. At birth he was left on the steps of a Paris church where a common woman who became his mother saved him. Tencin never recognized d'Alembert as her son even though he was a superstar of the Paris salon scene.

Well known as a witty conversationalist and free thinker, d'Alembert was a major contributor to the Encyclopedie. A friend and colleague of Denis Diderot and Voltaire, he submitted articles on many topics and served as the editor of the math and science submissions. He contributed to the world of philosophy in many different areas such as literature, law, religion, history, music, and of course in many areas of math and science, especially physics.

Denis Diderot is responsible getting the Encyclopedie project started and keeping it alive. During the Age of the Enlightenment, this was the most popular work, and to be a member of the Salons of Paris you had to be closely acquainted with the contents. Diderot served as the general editor and was responsible for securing the financial support for the enterprise.

Diderot wrote the Discours Preliminaire, introducing readers to the voluminous work. He presents the series as a unified view of contemporary knowledge and traces the development and interrelationship of its various branches. He shows how the many diverse areas of knowledge explored are all part of a cohesive structure that is symbolic of the knowledge that the philosophes sought to find.

Cesare Beccaria wrote the famous work, On Crimes and Punishments, published in 1764. This was the first succinct and systematic statement of principles governing criminal punishment. It represents a major advance in criminological thought dealing with issues that are still controversial today.

Beccaria notes that the objective of the penal system should be to devise penalties severe enough only to achieve order; anything in excess he considered tyranny. The effectiveness of criminal justice depends largely on the certainty of punishment rather than on its severity, according to Beccaria. He was the first modern writer to advocate the complete abolition of capital punishment, and many, therefore, regard him as a founder of the abolition movements that have lasted up to the present day.