Magia naturalis and demonic magic: a contested boundary

For the humanists of the fifteenth century the word “magic” was a problem. On the one hand it referred to the wisdom of the Persian magi, the sages who according to the Gospel of Matthew had paid homage to Christ; on the other it recalled pacts with demons, condemned by theology for centuries. To be able to speak of magic without being accused, Renaissance philosophers developed a distinction destined for great success: that between magia naturalis, founded on the hidden forces of nature, and demonic magic, which invokes evil spirits.

The theological condemnation

The starting framework had been set by Augustine in De civitate Dei, where the magical arts are described as traffic with demons. Thomas Aquinas, in the Summa contra gentiles, added a decisive argument: signs, figures and words have no power over matter in themselves, so if they produce effects it is because someone, a demon, interprets them as a signal. From this arose the idea of the pact, explicit or tacit, which made suspect every practice based on characters and invocations.

In the late Middle Ages this doctrine fed a growing hostility towards learned magic, that of astrological treatises and books of talismanic images. One example is the condemnation of twenty-eight magical propositions pronounced by the Paris faculty of theology in 1398, under the influence of the chancellor Jean Gerson. Anyone wishing to deal with these matters therefore had to show that the forces at work were natural.

Ficino and Pico: a magic without demons

Marsilio Ficino, in De vita of 1489, presented his indications on the use of music, light and images as a natural medicine, operating through the spirit of the world and not through the intervention of personal spirits. He himself, however, let some hesitation show, and had to defend himself against accusations with an Apologia. Pico della Mirandola was more decisive: in the Oratio and in the magical theses of 1486 he distinguished a magic that depends entirely on the work of demons, which he rejected, and a magic that is the consummation of natural philosophy.

According to Pico the natural magician creates nothing new. Like the farmer who weds the vine to the elm, he unites what nature has already disposed to be joined, and so “marries” earth to heaven, bringing to light virtues that God has sown in the world. The agricultural image, taken up by many later authors, became almost the emblem of licit magic and of its claimed innocence.

Agrippa and Della Porta

Cornelius Agrippa accepts the distinction but complicates it. In De occulta philosophia natural magic occupies the first book, while the third ventures towards ceremonial magic, concerning divine names, angels and intelligences. Agrippa insists that the true magus must be pious and shun goetia, the magic of impure spirits, but many readers refused to believe him. In De incertitudine et vanitate scientiarum, printed in 1530, he himself distanced himself from the magical arts.

A generation later the Neapolitan Giambattista Della Porta published Magia naturalis in 1558, expanded to twenty books in 1589. Here natural magic becomes a collection of secrets of nature, optical experiments with lenses and mirrors, technical procedures and curiosities of every kind: a bridge, in some sense, towards the experimental philosophy of the seventeenth century, which would nonetheless reject its assumptions.

The boundary between the two magics always remained fragile, and the courts hardly ever took it into account. The English historian Daniel Pickering Walker, in his 1958 study Spiritual and Demonic Magic from Ficino to Campanella, showed how precisely this unresolved tension runs through the whole magical philosophy of the Renaissance, from Ficino to Tommaso Campanella.