‘The same atoms,’ Lucretius points out, ‘constitute sky, sea, lands, rivers and sun: the same compose crops, trees and animals.’ But if the atoms have no qualities other than size, shape and motion, how can they give rise to our noisy, colourful, scented, textured world? The answer, he explains, is that combinations and arrangements of atoms can take on qualities they do not possess individually. He employs the analogy of letters and words.
The 26 letters of the Roman alphabet can be combined into at least 100,000 meaningful words of the English language. Some linguists maintain that there are up to 1,000,000 words in English, though nobody’s vocabulary could have that breadth. And from even 100,000 words, millions of intelligible, grammatically correct sentences, expressing millions of thoughts and experiences and observations can be formed. Sentences have ‘emergent’ qualities that the letters and spaces composing them do not possess. They can be gentle or inflammatory. Unlike individual letters, they can communicate information, persuade, mislead, enable actions or start a riot. In an analogous way, Lucretius suggested, starting with combinations of ‘primitive’ elements with only a few properties, everything in the noisy, colourful world of experience can be produced.
When it came to vision and hearing, the ancient Epicureans held the interesting theory that sights and sounds were rather like scents. ‘Various sounds,’ says Lucretius, ‘are continually floating through the air … When we walk near the sea, a briny taste often makes its way into our mouth; … From all objects emanations flow away and are discharged in all directions on every side.’ When we smell bacon frying in another room or catch a whiff of someone’s perfume, we can infer that tiny particles made up of still smaller atoms have drifted into our noses from some distance. Tiny particles flow into our eyes and ears as well. For the Epicureans, when I see a tree, a thin ‘film’ of coloured particles actually detaches itself from the tree and floats into my eyes. Objects, they supposed, were constantly emitting these films from their surfaces and so wearing away, while replenishing their substance by absorbing particles from the environment.
Lucretius noted how dependent colours were on the conditions of observation and the lighting. This was especially noticeable in the case of the sea, whose colour varies from hour to hour. Colour, he inferred, must depend on the arrangement of atoms in physical objects and liquids, and how it is affected by light and affects our eyes. The same must be true for scents and tastes: the particles of what we smell and savour enter our bodies and are perceived as pleasant or unpleasant, as the case may be. He pointed out that physical processes such as grinding could change a dark substance like horn to a white powder. He drew from this a correct conclusion: objects do not have fixed, permanent colours, though colours appear to be relatively stable. The tomatoes on my countertop, for example, tend to look the same uniform shade of red to me whenever I see them, regardless of the lighting. Artists, however, are trained to notice the subtle differences that depend on illumination.
Today, no one who has actually studied the visual system believes that vision occurs via films peeling off the surface of objects and travelling through the air. Nor do we believe that the entities that will survive the collapse of our universe will be anything like a dust mote, only smaller. Nevertheless, Epicurean physics is the ancestor of our modern physics, and the developing notion of the atom can be traced from its first appearance in ancient Indian and Greek philosophy. Chemistry employs the notion of an atom of a chemical element such as carbon, gold or uranium, and light is often described as a stream of particles, the photons. But we now recognise that the chemical atom is itself a composite of subatomic particles, and that it can be split, liberating vast quantities of energy – a concept the Epicureans did not recognise.
According to Epicurean cosmology, nothing that we are aware of and experience can be considered permanent. Where the universe that we probe with radio telescopes and other devices is concerned, it will probably last for a few more billion years before returning to its elements, or mutating into some new form altogether. We cannot, however, rule it out that some singularity, unpredictable by our current physics, should bring about the total collapse of our universe two minutes from now. Once all of life disappears from the universe, it may never return. Or universes may cycle in and out of existence, reinventing time, space and matter, and bringing forth new and wondrous forms, even intelligent beings.
In the meantime, everything we see, touch and know about not only can be, but will be reduced to its unknown constituents. ‘Time,’ Lucretius says, ‘wholly destroys the things it wastes and sweeps away, and engulfs all their substance.’ Nothing in nature or made by us endures. This applies to our clothes and furnishings, which wear out, to our bodies that weaken and sag and are eventually reduced to dust. It applies to empires, to economic systems and to our relationships with friends and relatives, even to those that are only brought to an end by death.
As long as our world remains intact, however, new things come into existence as the elements move, interact and combine. New life replaces the old with the birth of children and grandchildren: ‘Venus escort[s] each kind of creature back into the light of life.’ We build new houses in new styles, sew new garments and invent new musical, artistic and political forms. We accept and sometimes welcome the changes in our relationships and the formation of new ones. ‘No visible object ever suffers total destruction,’ Lucretius points out, ‘since nature renews one thing from another, and does not sanction the birth of anything unless she receives the compensation of another’s death.’
The Epicureans drew several important consequences from their views about the nature of reality. The world of familiar objects – tables, chairs, plants and animals, puddles and ponds – its colours, scents and sounds, they realised, is an appearance. And although everything except the atom is perishable, some things are more stable and can endure longer than others. Organisms and boulders are stable by comparison with soap bubbles or houses of cards.
Taking this perspective on board, we realise that the perception of what we call reality depends on the observer, who is nothing but an aggregate of atoms (or their modern equivalent). Human beings are similar enough in our constitutions that we can all perceive tables and chairs, plants and animals, airplanes overhead, sails in the distance, red and green traffic lights, when they are a suitable distance away and our eyes are working normally. And human bodies are different enough from one another that we disagree about what dishes, colour combinations and perfumes are appealing. But the visual world of an eagle or a panther, the odiferous world of a dog, or that of a lizard that can smell carrion several miles away, must be different from ours, insofar as their bodies and sensory organs are composed of differently put-together particles. We should beware of supposing that human perception sets any kind of standard, as though other animals enjoy enhanced or suffer from defective versions of our perceptual abilities.
Individual differences can be strongly marked when it comes to the values – positive or negative – we ‘see’ in objects, situations and events, or feel ‘belong’ to them. We believe that strawberries are truly red and truly delicious when ripe, and that premeditated murder for financial gain is truly wrong. But we can only make such confident judgements because certain arrangements of particles, those composing strawberries or making up the pixels on a television screen at a certain time or the print in a newspaper article, make more or less the same impact on different human sensory systems and minds.
When we disagree in our perceptions or our moral judgements, the reason for this is not hard to fathom. We are similar but not identical, and the world presents itself a little differently to everyone. Please don’t jump to the conclusion, however, that an Epicurean must be a relativist who thinks everyone’s judgement is as good as everyone else’s when it comes to questions of taste or morality. The actual Epicurean position on the issue of relativism is far subtler.
To return to the theme of atomic reality, the realisation that everything is fragile and tends with time to get broken up points us in two directions. First, we should not be surprised that our wine glasses break, our houses crumble, stock market runs come to an end and our relationships go