Isaac Newton and alchemy: the secret manuscripts of the father of physics

For two centuries Isaac Newton was the very symbol of modern science: the man who with the Philosophiae naturalis principia mathematica of 1687 had reduced the motion of the planets to mathematical laws. The fact that the same Newton had devoted decades to the study of alchemy was known to few and was regarded as an embarrassing chapter. Only in the twentieth century, with the dispersal and then the study of his manuscripts, did this part of his activity become a central theme in the history of science.

The 1936 sale

On Newton's death in 1727 his papers passed to his family and then to the Earls of Portsmouth. Part of the scientific papers was donated to the University of Cambridge in 1888, while the manuscripts on alchemy and theology were judged to be of little interest. In 1936 they were auctioned by Sotheby's in London and dispersed among many buyers.

The economist John Maynard Keynes bought a large number of them and bequeathed them to King's College, Cambridge, while the scholar Abraham Shalom Yahuda collected mainly the theological writings, now kept in Jerusalem. Keynes, having read them, wrote a famous essay in which he argued that Newton had not been the first of the age of reason, but rather the last of the magicians. The verdict, deliberately provocative, caused much debate.

What Newton read

Newton's alchemical writings are estimated to exceed a million words, largely transcriptions, extracts and commentaries on the works of others. Newton carefully copied medieval and modern texts, compared versions and compiled indexes of terms. Among the authors he studied most closely was Eirenaeus Philalethes, a pseudonym behind which historians now recognise the chemist George Starkey, born in Bermuda and educated at Harvard,, active in London around the middle of the seventeenth century.

Newton signed some of his alchemical notes with the anagram Ieova sanctus unus, derived from his Latin name, Isaacus Neuutonus. He kept these studies largely private, sharing them with a few trusted correspondents, including the natural philosopher Robert Boyle and the philosopher John Locke, both of whom were also interested in the transmutation of metals. His reserve was dictated both by the alchemical tradition of secrecy and by the caution of a public man.

Alchemy and the new science

Historians debate how far alchemy influenced Newtonian physics. The American scholar Betty Jo Teeter Dobbs, in her book The Foundations of Newton's Alchemy of 1975, argued that alchemical ideas about the active forces of matter helped Newton to conceive of attraction at a distance, which the Cartesian mechanists regarded as an occult quality. Other scholars prefer to see Newton's alchemy as a programme of chemical research, conducted with the same experimental rigour as his work on optics.

The case of Newton does not show a direct continuity with Agrippa, whom he does not seem to have studied with particular attention. It does show, however, that the Hermetic and alchemical tradition of the Renaissance did not disappear with the scientific revolution, but continued to occupy the minds of some of its protagonists, in forms often kept hidden.

This discovery has changed the way the birth of modern science is told. The boundary between magic, alchemy and natural philosophy, which nineteenth-century textbooks drew with confidence, now appears far more blurred. And it is precisely in this border zone that the most lasting part of the legacy of Renaissance magic lies.