Sympathy and antipathy: the secret friendships of nature

Iron runs towards the magnet, the heliotrope, as its Greek name says, turns towards the sun, some plants seem to thrive beside one another and others to wither. For the ancients and for the philosophers of the Renaissance these phenomena were not isolated curiosities, but manifestations of a general law: the things of the world are bound by hidden friendships and enmities, by sympathies and antipathies. Cornelius Agrippa regarded this network of affinities as the very ground on which natural magic could operate.

The Stoic sympatheia

The Greek term sympatheia literally means “suffering together”. The Stoics, in particular Chrysippus in the third century BC and later Posidonius, used it to describe the solidarity of all the parts of the cosmos, conceived as a single body animated by pneuma. The most cited example was the tides, which follow the motion of the Moon: a sign that a celestial event can have consequences on earth without apparent contact. Cicero, in De divinatione, reports these arguments when setting out the Stoic position.

On this basis the Stoics also defended divination: if everything is connected, a sign observed in one part of the world, in the flight of birds or the entrails of a victim, can announce an event that will occur elsewhere. Sympathy thus became a true theory of universal communication, and precisely for this reason it was criticised by the sceptical Academics, as the second part of Cicero's dialogue shows.

Plotinus and magic as sympathy

Plotinus, in the fourth book of the Enneads, tackled the problem of magic directly. Spells, he writes, work not because they compel the gods, but because the cosmos is a single living being, in which every part feels what happens to the others, like a string that vibrates when another string tuned to it is plucked. The true magician, from this perspective, is the universe itself, with its attractions and repulsions.

Marsilio Ficino translated and commented on Plotinus, published in Florence in 1492, and drew inspiration from him for De vita. Agrippa in turn took up the legacy: in the first book he lists numerous traditional examples of friendship and enmity between animals, plants and stones, drawn largely from Pliny's Natural History.

From medicine to the powder of sympathy

In 1546 the Veronese physician Girolamo Fracastoro published De sympathia et antipathia rerum, in the same volume as his celebrated treatise on contagion. Fracastoro tried to explain natural attractions through the emission of invisible particles, an attempt to give sympathy a physical basis. The word thus entered the language of university medicine.

In the seventeenth century the doctrine found controversial applications. In England a dispute flared up over the “weapon-salve”, which according to its Paracelsian supporters acted on a wound by treating the weapon that had caused it. In 1658 Sir Kenelm Digby published the discourse he had given at Montpellier on his “powder of sympathy”. Modern medicine has rejected these beliefs, which remain documents of the history of ideas.

Universal sympathy was at once a metaphysics and a way of observing nature. It suggested that behind appearances there were bonds to be discovered and invited the search for relations between distant phenomena. It was an intuition that later science would translate into forces, attractions and fields, while abandoning the idea, dear to Agrippa, of a living cosmos that feels and responds.