Titus Lucretius Carus (ca. 99 BCE – ca. 55 BCE), engraving of a bust. [Photo courtesy of Wikimedia Commons.]

ast year marked the six hundredth anniversary of an important event in the history of humanist literature and, so far as I can tell, no one made much of a fuss about it. That’s a shame, because the rediscovery of one of the most remarkable, influential, and enduring visions of what it means to be a classical humanist – the long Latin poem On the Nature of Things – is surely an event that humanists everywhere might well want to celebrate.

The poem was written in the first century BCE by Titus Lucretius Carus, about whom we know virtually nothing, other than the fact that he wrote the work and, according to completely unreliable Christian gossip produced years after his death, was driven mad by a love potion administered by his wife and eventually committed suicide at age forty-four.

On the Nature of Things is, first, a long celebration of the philosophy of Epicurus, a Greek philosopher of the previous century, who insisted that the best life was one devoted to avoiding pain and seeking, through sense experience and reason, the pleasures most appropriate for human happiness, particularly those derived from a disciplined contemplation of the world by a mind acquainted with the material causes of natural phenomena. The attainment of such a state is threatened by anything which upsets the tranquillity of the mind by making human beings anxious, fearful, or cruelly hostile to one another. The principal source of such threats (although not the only one), according to Lucretius, is religious belief.

The power of religion, Lucretius insists, comes from two main sources. The first is the wonder and terror people experience when they are confronted by certain natural events, particularly disasters (storms, earthquakes, outbreaks of disease, and so on) or unusual phenomena (eclipses, comets, and volcanic eruptions), feelings they deal with by accepting the cruel and ridiculous superstitions religion provides. And the second source is the doctrine of the immortality of the soul and the afterlife, which often fills people with dread, inhibits their ability to recognize and enjoy the pleasures which are possible in this life, and fosters a morbid fear of death.

Unlike some modern secular writers keen to discredit religion, Lucretius realizes that merely mounting a frontal assault on the foolishness of believers or providing a catalogue of religious atrocities will not achieve what he wants. He has to offer an alternative way of understanding the world and, most important of all, persuade his readers that his new vision is worth attending to as a firm and rewarding basis for the good life. That is why, he keeps telling us, the poetic form he has adopted is important: he is administering medicine to children; the poetry, like the honey physicians spread around the lip of the cup, is designed to make a potentially bitter potion palatable.

The medicine Lucretius offers is an extensive explanation of how Epicurus’ atomic theory can account for everything we wish to understand. The entire universe is made up of nothing but atoms and empty space. These atoms are in constant linear motion, and from time to time they randomly swerve and collide. In these collisions, some atoms combine to form the different substances we see all around us. Because of the random swerve, this universe is the product of chance and is not governed by deterministic laws (on that basis of this claim Lucretius preserves the idea of free will). The supply of atoms is infinite, but the number of different atoms is not. Hence, the huge variety of material things we perceive in our world comes, not from a large number of different atoms but from the many different combinations of a relatively small number. To clarify this point, Lucretius repeatedly uses an analogy to the letters of the alphabet whose combinations can make up countless different words. On the basis of this thoroughly materialistic theory, Lucretius argues, we can understand everything that occurs in nature and thus have no need of religious explanations.

Lucretius, one should note, does believe in gods (he promises to discuss their material being in detail but never does so). However, these deities, living in perfect contentment, have no interest in human beings and play no role at all in what goes on in the material universe. What could possibly motivate them to do so? Why would they even bother? Human beings should contemplate the gods’ perfections, but we have no business invoking them in order to explain natural events.

Most of the poem is taken up with applying this materialistic view of natural processes to a wide range of topics, from the infinite nature of the universe and the movement of the celestial bodies to human perception, heredity, sexuality, the material history of the world and of major natural events, and more. These explanations are almost invariably interesting, if at times somewhat over-ingenious, and from time to time we do get useful hints about how to make our lives more pleasurable or less painful (for instance, satisfying our sexual desires with prostitutes is advisable if we wish to avoid the pains of married life). Of particular importance to Lucretius is the material (and hence mortal) nature of the soul, obviously a crucial part of the case he is making against religious belief (Book 3 of the poem ends with a famously eloquent series of seventeen consecutive arguments for the mortality of the human soul).

What’s remarkable about Lucretius’ materialistic view is that he is not particularly interested in anything resembling a general law governing a particular phenomenon. As long an explanation for a natural event (e.g., for the movement of the sun or the stars) is reasonable, satisfies sense experience, and does not require divine intervention, it is acceptable. If there are three or four possible explanations that all satisfy these criteria, they are all equally acceptable, and there is no point in trying to sort out which one might be the best. He even expresses a certain contempt for someone who would want to do that. Lucretius concedes that in our world there must be only one explanation but, given that there are countless other worlds in the universe where other explanations may be valid, he sees little point in trying to settle on just one of the alternatives as correct.

This lack of interest in general laws stems from Lucretius’ desire, as an Epicurean, to privilege sense experience over everything else. Our perceptions are more important than our reasoning about perceptions because sense experience, even though it can at times apparently be deceived by illusions, is more reliable than reason. Lucretius, unlike the pioneers of modern science, has no interest in urging his readers to become masters of nature by diligently searching for general laws governing a wide range of particular perceptions. What he does want them to do is look closely at the world, appreciate the material causes underlying all phenomena, and derive pleasure from the wonders all around them. This activity, he assures his readers again and again, is a much better way to live than to spend one’s time racked with religious or political worries, ambitions, and fears. Wise people seek to spend their time, not in the forum, temple, legislative assembly, or library, but in the garden.

And what exactly is the vision of nature Lucretius wants us to appreciate? The most obvious feature is its extraordinary dynamism. Everything is always moving all the time. Objects may be apparently at rest, but their particles are always in restless motion; matter is constantly streaming to and from them; the air is full of particles in motion (sunlight, images, smells, noises, and so on) and its composition is always changing: corporeal stuff enters and leaves the cosmos continuously, below the earth all matter is constantly shifting, and everywhere around us the battle between heat and water continues without pause. The earth is constantly leaning over and threatening to collapse, like a precarious, ill-constructed building, then righting itself, and then moving once again, often with cataclysmic results. No writing about nature is so dominated by verbs of motion, change, collision, combat, creation, explosion, destruction, and dissolution.

This vision is reinforced by the way Lucretius spends so much time on phenomena involving flowing liquids and constantly shifting atmospheric conditions, those features of nature which most resist accurate prediction. He is far more interested in the behaviour of clouds, winds, and lightning, for example, than he is in the regular motions of the planets. Yes, he does acknowledge the repetitive patterns, like the returning seasons and the monthly phases of the moon, but what really fires his imagination are the sudden and unexpected phenomena, like earthquakes, volcanic eruptions, thunderbolts, rainstorms, whirlwinds, torrential floods, and disastrous plagues. Allied to this constant activity is the randomness of nature. At the heart of every natural process is the random swerve, which cannot be reduced to some universal deterministic law. And, like that swerve, nature operates suddenly, unpredictably, and often with enormous force. The overwhelming sense one gets is of an intense dynamism, whose effects we can acknowledge but cannot contain, control, or foresee.

Amid the descriptions of all this active uncertainty there are constant reminders of the natural spectacle everywhere around us. Again and again, Lucretius links the point he is making to a sudden, sharply focused perception of a natural scene: a horse halfway across a flowing river, sheep grazing in the meadow, trees rubbing in the wind, lions going berserk in battle, garments hanging up beside the sea, huge dogs playing with their pups, a cow searching for her slaughtered calf, the appearance of oars above and below the water, stars glimmering in the heavens, a race horse in the starting gate, the build-up of clouds before a storm, and on and on. The poem is always directing our attention to the wonders of material processes, which we can appreciate fully only if we abandon fanciful stories about the gods or elaborate explanations and take the time to perceive what is going on, moment by moment.

Lucretius is often accused of being extremely pessimistic, thanks especially to his emphatic assertions about the eventual destruction of the world and the dissolution of everything in our cosmos. In addition, his poem frequently reminds us of the destructive effects of natural processes and of the mutability of everything. Yes, such passages provide plenty of material for gloomy reflections. But offsetting this is the enormous delight he communicates in his pictures of the natural world and the confident joy he expresses in thinking about it as a source of unending activity, beauty, sublimity, power, and wonder. Like Socrates in Plato’s early dialogues, Lucretius is urging us to have the courage to reorient our priorities to nature and to our own lives, and (again, like Socrates) the most persuasive means he has at his disposal is an insight into his own intense convictions and his determined courage in the face of an unpredictable, powerful, and dangerous but always fascinating world.

At times one even gets the impression that Lucretius wants us to reach an understanding of nature through our particular perceptions of natural phenomena on a case by case basis. His materialistic atomic theory and his two guiding principles (sense experience and reason) will give us the tools to carry out such a task, so that we can then share the enthusiasm he feels by looking all around us with a heightened sensitivity to the wonders of nature. One commentator has pointed out that Lucretius at times uses the word foedus (meaning treaty) to describe this relationship: rather than seeking out and imposing universal laws on our experience of nature, we should begin and end with our perceptions and, as it were, arrive at an understanding by some mutual negotiation. Whether this qualifies as a scientific stance is, I suppose, open to debate – it certainly flies in the face of our accepted notions of what science is all about – but it is a call to reorient the way we look at, comprehend, and feel about the world and about ourselves. If we need a “proof” of the value of such a stance before signing on, we find it, not in the scientific or philosophical arguments, but in the character of the narrator of the poem, in the intense confidence, resolution, and delight he reveals in contemplating this vision of the nature of things.

However we choose to characterize Lucretius’ treatment of nature, there is no questioning the astonishing popularity of On the Nature of Things in the centuries after it was rediscovered. Since then, the list of those who have acknowledged Lucretius as an important influence reads like a Who’s Who of Western Culture. It includes, as one might expect, those who welcome the poet’s attacks on organized religion and endorsement of reason and sense experience in pursuit of a life of moderate pleasure (e.g., Voltaire, Diderot, Hume), but many pious Catholics, like Pierre Gassendi (who tried reconciling Lucretian atomism with Christian doctrine) had no trouble embracing the work. Molière undertook a translation of the poem (now lost), Montaigne covered his copy of Lucretius with extensive annotations and filled his essays with quotations from the poem, Kant drew on ideas from Lucretius in his early scientific writing, and leading Romantic poets – Wordsworth, Coleridge, Shelley – found inspiration in Lucretius, along with a slew of nineteenth-century figures: Goethe, Arnold, Tennyson, Pater, Whitman, and Marx (who wrote his PhD dissertation on Lucretius), among many, many others. Thomas Jefferson owned eight copies of On the Nature of Things, declared himself a firm disciple of Epicurus, and may have derived the phrase “pursuit of happiness,” at least in part, from his reading of Lucretius. The influence of On the Nature of Things was so pervasive in European culture that, for one historian at least, Charles Darwin’s claim (in answer to suggestions that he may have derived the idea of natural selection from Lucretius) that he had not read the poem seems rather like Milton’s claiming he had not read Genesis before writing Paradise Lost.

Why a two-thousand-year-old poem should have had such an extraordinary effect on intellectual life in modern Europe invites one to speculate. The work’s popularity was obviously linked to the explosion of interest in Greek and Roman literature initiated during the Renaissance and to the subsequent emphasis on Classical Humanism in the schooling of educated Europeans, for On the Nature of Things is the best single demonstration of what Classical Humanism means in practice. Beyond that, it seems clear that post-Reformation humanists who wanted to put destructive religious and political disputes behind them found in Lucretius their ideal poster child: an intelligent secular voice insisting on a very personal vision of a life devoted to avoiding pain and enjoying the pleasures derived from a scientific understanding of nature. Even if the modern world, for the most part, had little use for Epicurean science, it continued to draw inspiration from a mind that could so passionately celebrate the wonders of a constantly changing universe and so courageously accept its own imminent dissolution.