French Natural Philosopher, Mathematician, and Priest
Pierre Gassendi is best known as the seventeenth-century rehabilitator of the atomism of the ancient Greek moralist and natural philosopher, Epicurus (341-270 b.c.). Gassendi found in atomism a way both to combat the extreme skepticism that had pervaded French intellectual life since the late sixteenth century and to overturn Aristoteleanism, which was the dominant philosophy and "science" of both the church and learned culture. Gassendi thus straddled a thin line between orthodox and heterodox ideas: on the one hand an ordained priest in search of certainty amid the skepticism brought about by a revival of ancient Greek Pyrrhonism and the disillusioning experience of the French Wars of Religion (1559-1598); on the other hand something of an iconoclast, whose stated goal was to overturn the metaphysical assumptions that had underpinned the church and intellectual authority since the Middle Ages.
Gassendi was born on January 22, 1592 in Champtercier, in the south of France. He became a doctor of theology in 1614 and was ordained a priest two years later. He mastered ancient Greek and Latin, mathematics, theology, and philosophy at an early age and began teaching philosophy at the University of Aix in Provence in 1617. Gassendi left Aix in 1622, as the Jesuits took over the school, and traveled throughout Europe for a number a years. Always compelled intellectually to dislodge the authority of Aristotle (384-322 b.c.), he began avidly reading Epicurus for that purpose in 1628. Gassendi worked on his Epicurean project throughout the 1630s; however it was not until 1647 that the first of his works on Epicurus was published. A more important work, the Animadversions on Book X of Diogenes Laertius, was brought out two years later; but not until three years after his death in October of 1655 was Gassendi's Opera Omnia, which contained his extensive commentaries on Epicurus, finally brought to light.
The atheist Epicurus had long been on the Church's most wanted list, so it is surprising on the surface that Gassendi was compelled to spend a lifetime resurrecting the works and theories of a heretic. Part of the explanation for this apparent contradiction is that Epicurus was an effective weapon against Aristoteleanism, which from an early age Gassendi found empty and useless. During his tenure at Aix, Gassendi taught his students that just as important as learning Aristotle was acquiring the tools needed to attack the ancient philosopher's philosophical system. Of course, one might also wonder about the piety of someone who attacked Aristotle in the early seventeenth century, but Gassendi defended himself writing that he found offensive both the blind veneration of Aristotle by learned authority and the way in which Aristotelean argumentation, dialectic, and rhetoric kept one from understanding the true reality of nature. Aristoteleans could deduce truths from their universal definitions of things in nature; for instance, from the premises that all stars are bright and the sun is a star. Aristoteleans could logically conclude that the sun was bright. But Gassendi thought such types of statements only told one about definitions; they did not necessarily reveal a truth about nature. Nature, instead, had to be understood using the senses alongside reasoning; experience, which the moderately skeptical Gassendi always recognized could deceive the sentient being, was the key to providing an instrument of proof about the real world and an antidote to radical skepticism.
Yet this might lead one to wonder why the empirical Gassendi embraced atomism—after all, no one had ever actually seen an atom. Gassendi's answer was that even though one cannot see atoms, one can induce their existence through the senses. For instance, one can witness the effects of an invisible and seemingly matterless wind on the branches of a tree, or one can smell an unseen fragrance before one sees the source from which it is emanating. Such phenomena suggested to Gassendi that the world is composed of smaller particles, which he further hypothesized were solid and indivisible, varied in shape, magnitude, and weight, and, variously configured, the building blocks of all the matter in the universe. Echoing Epicurus, Gassendi thus thought the universe was in essence atoms and the void in which they were contained. Unlike Epicurus, however, Gassendi also made room in the cosmos for God and human souls, those things which Epicurus had adopted atomism specifically to reject.
Gassendi's lifelong balancing act between heterodox and orthodox ideas made him one of the most interesting intellectual figures in the seventeenth century. He rejected Cartesian deduction in favor of induction but was as much a mathematician as René Descartes (1596-1650) and thus also recognized the importance of deduction used in union with sense experience; he sought to explain the universe in mechanistic terms, but, always a moralist, he saw proof of God in nature everywhere he looked. In this first sense, Gassendi is a forebear of John Locke (1632-1704); in the second, he resembles Isaac Newton (1642-1727). Neither comparison is accidental. Gassendi's once formidable reputation may not have survived the early modern period intact—in his day he stood on even ground with Thomas Hobbes (1588-1679) and Descartes—but he nonetheless had a deep impact on the generation of philosophers and scientists who followed in his wake.