I am an Epicurean.

—Thomas Jefferson

ATOMISM IN EARLY CHRISTIANITY

Atomism isn't mentioned in the Bible, although a reference to Epicureans during a visit by Paul to Athens can be found in the Acts of the Apostles. “What will this babbler say,” they asked (Acts 17:18). (Aside: When I grabbed my King James Bible to check this reference, it opened right to the page.) However, there can be little doubt that atomic philosophy, if not atomic physics, conflicts with Christian teaching—not only with scriptures but also with the teachings of Plato and Aristotle that had great influence on Church theologians.

In the fifth century, Augustine of Hippo was quite explicit in rejecting any notion of the primacy of matter:

Let those philosophers disappear, who attributed natural corporeal principles to the intelligence attached to matter, such as Thales, who refers everything to water, Anaximenes to air, the Stoics to fire, Epicurus to atoms, that is to say, to infinitely small objects that can neither be divided nor perceived. Let us reserve the same fate to all the other philosophers, who are too numerous to name and who claimed to have found in simple and combined substances, lifeless or living, indeed in what we call material bodies, the cause and principle of things.1

Bernard Pullman provides a long list of disagreements between atomism and Christianity.² I will mention just a few of the most important.

To avoid confusion, here and in the remainder of this book I will refer to the atomists’ notion of an eternal, uncreated universe containing multiple worlds with the modern designation multiverse. The term universe will then generally refer to our universe and other individual islands within the multiverse. Clearly, an eternal multiverse is at odds with the Christian belief in creation. Furthermore, either our universe, our galaxy, our sun, our Earth, and our form of life are unique manifestations, or Jesus had to die on the cross countless times in all those universes, on each and every inhabited planet. Neither case makes much theological sense. We humans like to think we are unique, and theology supports that view, but then why would God create so many other universes, other galaxies, other stars, other planets, and (most likely) other forms of life?

Christian theology also has a problem with the nature of time. If God were perfect, unchanging, and eternal, why would he have made a change in creating the world? Augustine, following Plato, thought he had solved the problem by saying God created time along with the universe. The atomists did not have to trouble themselves over the question because they did not regard time as an element of reality but simply as a relation between events. This is also a modern concept. As Einstein said, “Time is what you read on a clock.”³

Another area of disagreement concerned the atomists’ attributing to chance the formation and evolution of worlds. To Christians, divine providence alone determines the fate of the universe. Recall from chapter 1 that this was also an area of disagreement with the Stoics, who regarded everything as predetermined by fate.

Obviously, the atomists’ view of the soul as material and mortal is unacceptable to Christians.

Throughout history, Christian theologians attacked the moral teachings of Epicurus, often misrepresenting them, as did the Stoics. Augustine wrote that “the pleasure advocated by Epicurus is the realm of beasts only.…[He] summons from his gardens a throng of his inebriated disciples to his rescue, but only to search frantically what they can tear apart with their dirty fingernails and rotten teeth.”4

ATOMISM IN THE MIDDLE AGES

While the Church did its best to suppress the writings of the Epicureans, medieval scholars of Christianity, Judaism, and Islam showed sufficient interest that knowledge of the philosophy and physics of atomism survived in their writings.⁵ Not all these chroniclers were necessarily supporters or proponents of atomism. None accepted its atheistic elements, but some found its physics congenial. The very fact that atomism conflicted with both Aristotle and the dominant monotheisms of the age made it a fit subject for philosophical and theological commentary, even if the goal was to refute that heresy.

While scriptures and the Church provided authority, reason was recognized as an auxiliary means by which God's laws could be accessed. Thus, with this caveat, some twelfth-century thinkers such as Adelard of Bath (1075–1150), Thierry of Chartres (ca. 1100–ca. 1150), and William of Conches (ca. 1090–1154) thought that the physics of atoms made sense. However, they were still a small minority.

Support of atomism was often associated with opposition to Aristotle. In the fourteenth century, William of Ockham (ca. 1288–1348), of “Ockham's razor” fame, was highly critical of Aristotle and claimed that matter could be reduced to “elementary particles.” He also agreed with the atomists that the universe was infinite and eternal. The Church condemned these theses in 1340.

Nicholas of Autrecourt (ca. 1299–1369) also defended atomism and repudiated Aristotle. However, he did not accept the Democritus-Epicurus view of the soul and considered it to be composed of two immortal spirits he called intellect and sense.

The only atomists within medieval Judaism were members of a schismatic sect called the Karaites. They were condemned by the most influential Jewish thinker of the time, Moses Maimonides (1135–1204), who opposed atomism as well as other Karaite doctrines. In his most famous work, The Guide of the Perplexed, Maimonides mentions Epicurus and, in one long sentence, tells us why we should ignore him:

As for those who do not recognize the existence of God, but who believed that things are born and perish through aggregation and separation, according to chance, and that there is no being that rules and organizes the universe—I refer here to Epicurus, his sect and the likes of him, as told by Alexander—it serves no purpose for us to speak about those sects; since God's existence has been established, and it would be useless to mention the opinions of individuals whose consciousness constructed their system on a basis that has already been overthrown by proofs.6

While Christendom was mired in the Dark Ages, Islam was going through its golden age. Scholarship flourished throughout the vast empire that had been conquered by the followers of Muhammad.⁷ Maimonides traveled extensively throughout these lands and wrote about what he learned.

Within Islamic scholarship, there existed a discipline called the Kalm that practiced the kind of theological rationalism I mentioned earlier, where reason is used to develop knowledge of God. In The Guide of the Perplexed, Maimonides described in some detail Arabic atomism as expressed in the Kalm.⁸

Basically, Arabic atomism followed Greek atomism in asserting that the universe is composed of miniscule indivisible particles that combine to give material substances. They also affirmed the existence of void. They viewed time as discontinuous, composed of instants.

As with Christian atomism, grave differences with the atomism of Democritus and Epicurus unsurprisingly arose when it came to God and the soul. In Islamic atomism, while everything is composed of atoms, these atoms are not eternal. In fact, they exist for only an instant and are continually re-created by God. Nothing depends on what went on before. There are no natural causes; God is the only cause. God has complete freedom and is responsible for every event that happens in the universe down to the finest detail.

Maimonides did not think much of the idea of perpetual creation. For example, he pointed out that long after God causes a person to die, he has to keep re-creating the leftover atoms such as those in teeth that survive for thousands of years.

Not all Arabic scholars went along with Kalm, notably the scholar best known in Europe, Averroes (Ibn Rushd, 1126–1198). However, as Pullman notes, “Among the three great monotheistic religions in the West, Islam [Kalm] was the first to proclaim that faith in a unique God, master of the universe, is entirely compatible with a corpuscular conception of the structure of matter.…That one can accept an atomic vision of the world regardless of one's position vis-à-vis God.”9

POGGIO AND LUCRETIUS

Meanwhile, atomism continued to be strongly opposed in Christendom. Although suppressed by the Church, a copy of De rerum natura luckily survived intact and, after being rediscovered in the fifteenth century, played no small part in the Renaissance and the scientific revolution that followed on its heels.¹⁰

Literary scholar Stephen Greenblatt has told the fascinating story of the rediscovery of De rerum natura in The Swerve: How the World Became Modern.¹¹ The central figure is Gian Francesco Poggio Bracciolini (1380–1459), who had served as apostolic secretary to five popes. Poggio had a deep knowledge of Latin, had beautiful handwriting, and enjoyed a long career as an influential layman within the Catholic Church bureaucracy. In 1417, he was out of a job after having served Baldassare Cossa, Pope John XXIII (ca. 1370–1419), the “antipope” who was deposed, stripped of his title, name, and power in 1413.12

Poggio was one of a group of scholars of the period called humanists who pored over classical Roman texts and sought out missing manuscripts. Relieved of his duties with the fall of Cossa, Poggio had time to follow this passion. At the time, monks were the major book preservers, and so monasteries were the first place to look for the desired texts. Poggio was drawn to a monastery in central Germany, the Benedictine Abbey of Fulda, founded in 744, which he had heard held a cache of old manuscripts. There he found a treasure of works by ancient Roman authors unknown to him and his fellow humanists. According to Greenblatt, even Poggio's smallest finds were highly significant.

However, these were eclipsed by his discovery of De rerum natura, a work more ancient than any of the others he uncovered in Fulda.¹³ Poggio was well aware of Lucretius, who had been mentioned by Cicero and Ovid. Ovid wrote: “The verses of sublime Lucretius are destined to perish only when a single day will consign the world to destruction.”¹⁴ According to Greenblatt, De rerum natura also influenced Virgil. Greenblatt says: “Virgil's great epic, the Aeneid, was a sustained attempt to construct an alternative to On the Nature of Things: pious, where Lucretius was skeptical; militantly patriotic, where Lucretius counseled pacifism; soberly renunciatory, where Lucretius embraced the pursuit of pleasure.”¹⁵

The monks in Fulda would not part with the manuscript, so Poggio arranged for a scribe to make a copy. After receiving the copy in Constance, he sent it to his friend and fellow humanist Niccolò Niccoli (1364–1437) in Florence, Italy, who then made another copy in his own elegant cursive script, which ultimately developed into italic type. That copy, Codex Laurentianus 35.30, resides today in Florence in the beautiful Laurentian Library designed by Michelangelo for the Medici family. I was able to personally view the manuscript on March 27, 2012.¹⁶ Figure 2.1 shows the first page.

Many more copies were spawned from these two, including one by the notorious Niccolò Machiavelli (1469–1527). That copy resides in the Vatican Library, MS Rossi 884.

Poggio and his contemporaries were not overly alarmed by the atheism in De rerum natura or, more precisely, by the indifference of the gods. After all, Lucretius died a half century before Christ and so had no opportunity to learn the “truth.” They approved of what Lucretius saw as the absurdity of the pagan practices of his contemporaries. Greenblatt points out, “even many modern translations of Lucretius’ poem into English reassuringly have it denounce as ‘superstition’ what the Latin text calls simply religio.”17

Still, the ideas uncovered in the poem had lain undiscovered for a thousand years and were bound to upset conventional thinking for no other reason than their strong unorthodoxy. Greenblatt eloquently summarizes the Epicurean message:

It is possible for human beings to live happy lives, but not because they think that they are the center of the universe or because they fear the gods or because they nobly sacrifice themselves for values that purport to transcend their mortal existence. Unappeasable desire and the fear of death are the principle obstacles to human happiness, but the obstacles can be surmounted through the exercise of reason.…All speculation—all science, all morality, all attempts to fashion a life worth living—must start and end with a comprehension of the invisible seeds of things: atoms and the void and nothing else.¹⁸

At the time Machiavelli was making his copy of De rerum natura in Florence, the notorious Dominican friar Girolamo Savonarola (1452–1498) was ruling the city with religious fanaticism, which eventually led to his excommunication and execution. Savonarola had spoken out against atomism, so Machiavelli wisely kept his copy a secret, and it survived the “Bonfire of the Vanities” in 1497 during which the followers of Savonarola burned books and other “objects of sin.” It was not until 1961 that Machiavelli's handwriting was identified and the copy in the Vatican was conclusively attributed to him.

Poggio was also able to avoid any taint of atheism resulting from his role as the discoverer of De rerum natura by separating the poetry from the message. Still the message circulated relatively freely until 1556 when the Florentine synod prohibited the teaching of Lucretius in schools. Nevertheless, this did not halt the printing of the poem in Italy and elsewhere. By then, editions had appeared in Bologna, Paris, and Venice, and a major edition in Florence had attracted much attention. Attempts to place De rerum natura on the Catholic Church's Index Librorum Prohibitorum (Index of Prohibited Books) failed, and Catholic intellectuals were allowed to discuss Lucretius as long as they treated it as a pagan fable.

Both Erasmus (ca. 1466–1536) and Thomas More (1478–1535) attempted to reconcile Epicurus and Lucretius with Christian thinking. More was, of course, the English statesman and scholar, the celebrated “Man for All Seasons,”19 who was beheaded by King Henry VIII for refusing to take an oath acknowledging the supremacy of the Crown in the Church of England. He was sainted in 1935.

Although admired for his steadfast loyalty to the Roman Catholic Church, More was a religious fanatic who wore a hair shirt and whipped himself until blood flowed. While he was Lord Chancellor of England from October 1529 to July 1535, More saw to it that six heretics were burned at the stake (not an unusual number at the time).

Still, More described himself as a “Christian humanist,” and his best-known work, Utopia, is a novel in Latin about an imaginary island where people live in peace under orderly social arrangements, free of the misery and conflict that then existed in Europe. More's Utopians were inclined to believe “that no kind of pleasure is forbidden, provided no harm comes of it.” However, while the citizens of Utopia are encouraged to pursue pleasure, those who think that the soul dies with the body or who believe that chance rules the universe were to be arrested and enslaved.²⁰

So, while More adopted Epicurus's “pleasure principle,” the seeking of pleasure had to be done under strict limitations. While people could worship any god they pleased, they could not follow Epicurus and Lucretius and worship no god or doubt the immortality of the soul.

While we are talking about sixteenth-century figures who were executed for their beliefs, let us not forget Giordano Bruno. He had a tangled philosophy that included Epicureanism. According to Greenblatt, Bruno “found it thrilling that the world has no limits in either space or time, that the grandest things are made of the smallest, that atoms, the building blocks of all that exists, link the one and the infinite.”21

Bruno championed Copernicanism at a time when the notion that Earth moves around the sun was unpalatable to both the Church and academic scholarship wedded to Aristotle. Bruno even went further than Copernicus in saying that the sun was not the center of the universe either, but that there was no center. Here again we find a brilliant centuries-old intuition, also held by the atomists, that would not be confirmed until the twentieth century, in this case when Einstein's 1916 general theory of relativity was applied to cosmology.

Bruno was burned at the stake in Rome on February 17, 1600.

GASSENDI

Pierre Gassendi (1592–1655) was a transitional figure who played an important role in moving the intellectual world from medieval thinking into the scientific age and helped make atomism a crucial element in that revolution. Gassendi was a French philosopher, priest, scientist, and classical scholar—a contemporary of René Descartes (1596–1650), Galileo, and Kepler.²²

Although as a priest he adhered to the theological elements of Church doctrine, Gassendi was a strict empiricist who insisted that knowledge of the external world is built solely on sensory evidence. He did not just talk about observations and experiments, he performed them.

Using telescope lenses provided by Galileo, to whom he wrote letters of support, Gassendi made numerous observations that helped establish the validity of Kepler's laws of planetary motion. In 1631, he became the first to observe a planetary transit of the sun (in this case, Mercury), providing strong confirmation of the Copernican model. This made possible the first estimates of distances between Earth, the sun, and the planets. Nevertheless, he was careful to say that other models were possible pending further data. Gassendi's other observations included sunspots, eclipses of the sun and moon, and the handles of Saturn that would later be identified as rings. He denounced astrology since it had no empirical support.

In physics, Gassendi studied free fall, measured the speed of sound, and showed that atmospheric pressure was lower on a mountaintop than at sea level, thus adding to the evidence that a void was possible. He performed a very significant experiment in which a stone is dropped from a moving ship, showing that the stone maintains the horizontal speed of the ship. Galileo had suggested this as a thought experiment to illustrate his principle that motion is relative. The best way to see this is from the point of view of an observer on the ship. That observer will see the stone drop straight down, whether the ship is moving or at rest. This was crucial in answering the quite--legitimate question addressed to Galileo: If Earth moves, why don't we notice it? The answer: Because there is no difference between being at rest and being in motion at constant velocity.23

Gassendi also made a major step toward the law of inertia as a result of this experiment. Galileo had thought of inertial motion as fundamentally circular. Gassendi realized that the natural motion of a body is in a straight line.

On the philosophical side, Gassendi was part of the growing movement that chipped away at Aristotelian scholasticism, which had dominated the universities of Europe for centuries. Recall that Aristotle claimed a duality of matter and immutable “essences.” Descartes made the same distinction with matter and “mind” to which most people still cling today. Gassendi maintained that regardless of whether there are any essences, we have no way of knowing about them. He also wrote a criticism of Descartes's Meditations and the reasoning behind cogito, ergo sum, basing it on empirical arguments. This generated a sharp reply by Descartes and further public debate between the two. Descartes had noted that we can only perceive appearances. Gassendi agreed, adding that appearances are all we can know about, which rules out any knowledge of essences.24

Gassendi's greatest achievement, however, was in rehabilitating Epicurus and bringing the atomic model to center stage in the new physics. Here he had to resolve a clear conflict with his empiricism. How can we say atoms exist if we can't see them?

While Gassendi agreed that we can't know anything for certain, he said we can still use indirect empirical evidence to support hypotheses about the invisible. Atomism is presented as the most likely hypothesis, what we now call “inference to the best explanation.” He claimed as such evidence the structures we see with a microscope, such as crystals.²⁵

Gassendi translated Diogenes Laertius's book 10 on Epicurus from The Lives of the Eminent Philosophers into Latin, along with ample commentary, in Animadversiones, published in 1649. While he followed the ancient atomists on the basic reality of atoms and the void, the priest Gassendi still asserted that they were put there by God.

Gassendi made further advances to atomism by proposing that light and sound are particulate. He provided speculative atomic accounts of planetary motion, of chemical and biological phenomena, and even of psychology. While none of his specific proposals, except the atoms of light, have withstood the test of time, they served to establish the notion that everything might someday plausibly be explained solely by atoms and the void.

Gassendi influenced any number of seventeenth-century scholars, including Robert Boyle (1627–1691) and John Locke (1632–1704). One interesting story is how the theory of nerve transmission developed by Thomas Willis (1621–1675) and Isaac Newton was based on a proposal by Gassendi. This supplanted the Cartesian model that separated the mind from the nervous system and instead treated nerves as communication lines with the brain.26

Newton adopted several of Gassendi's ideas, such as the particulate nature of light that was in opposition to the wave theory proposed by Robert Hooke (1635–1703) and Christiaan Huygens (1629–1695). In short, Pierre Gassendi was an important, insufficiently recognized contributor to the scientific revolution that followed.