The Occult Sciences: Astrology, Alchemy and Magic in History

The occult sciences were the disciplines that claimed to study and use the hidden powers of nature: above all astrology, alchemy and magic, together with divinatory arts such as geomancy, chiromancy and physiognomy. In medieval and early modern Europe they were not a fringe pursuit but part of learned culture, taught alongside astronomy and medicine, patronised by princes and debated by theologians. Their prestige faded with the Scientific Revolution, but they survived in popular almanacs and were revived in the nineteenth century as the core of modern occultism.

What Were the Occult Sciences?§

There was never a single official list of occult sciences, and the phrase itself became common only gradually. Medieval authors more often wrote of particular arts: the "science of the stars", the "art of alchemy", "natural magic", or the "notory art" of acquiring knowledge through prayer. What united these disciplines, in the eyes of later writers, was that each claimed to work through powers that were real but hidden, and that each combined theory with practice. They were sciences in the older sense of scientia: organised bodies of knowledge with their own authorities, techniques and texts.

Historians now speak of the occult sciences as a family of related disciplines rather than as a fixed category. The family included astrology and astrological image magic, alchemy, natural magic, ritual or ceremonial magic, and a range of divinatory techniques, and it overlapped with medicine, mathematics and theology. Lynn Thorndike's monumental History of Magic and Experimental Science showed long ago how closely these subjects were intertwined with what we would now call science.

Occult Qualities in Medieval Natural Philosophy§

The intellectual basis of the occult sciences lay in Aristotelian physics. Every body was composed of the four elements and possessed the corresponding manifest qualities: hot, cold, wet and dry. Yet many effects could not be explained by these alone. A magnet attracted iron, the torpedo fish numbed the hand that touched it, certain drugs purged particular humours, and some gems were said to protect against poison. Philosophers called the powers behind such effects "occult qualities" or "specific forms", and many traced them to the influence of the heavens acting on matter.

This was a respectable explanatory category, not a confession of superstition. Physicians invoked it to explain why remedies worked; theologians invoked it to separate natural wonders from miracles and from the deceptions of demons. The question of what was natural, what was demonic and what was divine became the central fault line running through every occult science. Our article on natural magic follows the idea of sympathy and antipathy in detail.

Astrology: The Science of the Stars§

Astrology was the most prestigious of the occult sciences and the one most closely tied to the universities. Its classical foundations lay in Ptolemy's Tetrabiblos and in the Hellenistic horoscopic tradition, which reached Latin readers chiefly through Arabic authors such as Abu Ma'shar and al-Qabisi. Medieval writers distinguished natural astrology, which forecast weather, harvests and the course of diseases and was widely accepted, from judicial astrology, which cast nativities and answered questions about individual fortunes and was suspected of denying free will.

Astrological medicine timed bloodletting by the moon, and astrology was taught as part of the mathematical sciences at Bologna, Paris and elsewhere. In the sixteenth and seventeenth centuries astrologers such as William Lilly, whose Christian Astrology appeared in 1647, reached a mass readership through almanacs. For the full history see our guide to astrology.

Alchemy: Transmutation and Medicine§

Alchemy sought to understand and perfect matter. Its practitioners worked on the transmutation of base metals into gold and silver, the preparation of powerful medicines and, for some, a spiritual transformation of the practitioner. Greek alchemy of late antique Egypt passed to Arabic writers, whose works attributed to Jabir ibn Hayyan introduced the sulphur–mercury theory of metals, and Latin translations from the twelfth century onwards launched a vast European literature.

Alchemy's status was always disputed. Pope John XXII condemned fraudulent alchemists in a bull of around 1317, and many writers mocked "puffers" who ruined themselves at the furnace. Yet alchemy also shaded imperceptibly into pharmacy, metallurgy and the "chymistry" of the seventeenth century, practised by Robert Boyle and Isaac Newton. Readers can explore the subject in the history of Western alchemy and in early English texts such as The Mirror of Alchimy (1597).

Natural and Ritual Magic§

Magic was the most controversial of the occult sciences. Learned authors distinguished natural magic, which manipulated the hidden virtues of herbs, stones and animals and was often defended as the summit of natural philosophy, from magic that worked through spirits. Giambattista della Porta's Magia naturalis (1558, enlarged 1589) treated natural magic as a collection of experiments and wonders, from optics to cosmetics; the English translation of 1658 is in our reading room as Natural Magick.

Between the two lay astral or image magic, which engraved talismans at astrologically chosen times in the belief that they captured celestial power. Its great source was the Arabic Ghayat al-Hakim, translated into Latin as the Picatrix in the thirteenth century. At the far end stood ritual magic, which invoked angels and demons through names, circles and seals, as in the Solomonic grimoires. Theologians from Augustine to Aquinas argued that any magic involving signs addressed to intelligences implied a pact with demons, and this argument shaped the later persecution of witchcraft. The Islamic background is examined in our article on Islamic occult sciences.

The Divinatory Arts: Geomancy, Chiromancy and Physiognomy§

Alongside the major disciplines stood a group of divinatory arts. Geomancy, which read sixteen figures generated from random marks, came from the Arabic 'ilm al-raml and became one of the most popular methods in medieval Europe (see geomancy). Chiromancy read character and destiny from the lines of the hand, and physiognomy from the face and body; both claimed descent from Aristotle, and physiognomy in particular enjoyed respectable status in medicine. Other techniques, such as oneiromancy (dream interpretation) and onomancy (divination by the numerical value of names), circulated in manuscript compendia and later in cheap print.

Agrippa's Three Books of Occult Philosophy (1533) gathered many of these arts into one system, and the Fourth Book attributed to him added geomancy and the Heptameron; both are available in our reading room in seventeenth-century English, as Three Books and the Fourth Book.

Decline and Survival after the Scientific Revolution§

The occult sciences lost their place in elite culture during the seventeenth century, though more slowly and ambiguously than is often assumed. Mechanical philosophers such as Descartes promised to explain all natural effects by matter in motion, and "occult quality" became a term of abuse; yet, as the historian Keith Hutchison has argued, many occult qualities were absorbed rather than abolished, with gravity itself attacked by Leibniz as an occult force. Astrology was gradually excluded from the universities, alchemy was separated from chemistry, and ritual magic was increasingly dismissed as superstition.

The occult sciences survived in popular print, in the practice of cunning folk and in Masonic and Rosicrucian circles. In 1784 the English astrologer Ebenezer Sibly began issuing A New and Complete Illustration of the Occult Sciences, a part-work combining astrology with magic and spirits (see Sibly's Illustration). In the following century Éliphas Lévi and his successors reassembled astrology, alchemy, magic, Kabbalah and tarot into a single "occult science", the foundation of the nineteenth-century occult revival.

Frequently asked questions§

Which disciplines counted as occult sciences?§

The core group was astrology, alchemy and magic, with natural, astral and ritual magic sometimes distinguished. Many authors also included divinatory arts such as geomancy, chiromancy and physiognomy, and later writers added Kabbalah and the tarot. The list varied by period and author.

Were the occult sciences considered science at the time?§

In the medieval and Renaissance sense, yes: they were organised bodies of knowledge with texts, theories and methods. Astrology in particular was taught in universities. Their legitimacy was nevertheless contested, especially where they seemed to involve demons or to deny human free will.

Why did the occult sciences decline?§

Several causes combined: the mechanical philosophy of the seventeenth century, the failure of astrological and alchemical predictions to stand up to scrutiny, religious hostility to magic, and changes in the universities and learned societies. They did not disappear but moved into popular culture and esoteric circles.

Sources and further reading§

• Tetrabiblos — Claudius Ptolemy, 2nd century
• Three Books of Occult Philosophy — Heinrich Cornelius Agrippa, 1533
• Natural Magick — Giambattista della Porta, 1658
• A History of Magic and Experimental Science — Lynn Thorndike, 1923
• Magic in the Middle Ages — Richard Kieckhefer, 1989
• Magic in Western Culture: From Antiquity to the Enlightenment — Brian P. Copenhaver, 2015
• The Secrets of Alchemy — Lawrence M. Principe, 2013
• A History of Western Astrology — S. J. Tester, 1987