Author’s Note

In case you were in any doubt, this is not an academic work. It is not something to be referenced, or consulted as if it were scholarly research. That is why I would like to introduce you to my sources, many of which do fit that description.

First, nothing compares to reading Jerome’s own descriptions of his life and work, his hopes and regrets. The Book of My Life, translated by Jean Stoner, is wonderfully entertaining. There are some moments of self indulgence in there, but it’s an autobiography — what can you expect? Also wonderful, though a lot, lot longer, is The De subtilitate of Girolamo Cardano, a translation from Jerome’s Latin by John M Forrester edited by the University of Edinburgh scholar John Henry. There are so many gems in these pages that I feel I will be mining them for the rest of my life. I do miss Jerome now that this book is finished, but I still get to hear his voice through these two works.

The Quantum Astrologer’s Handbook would never have been written without Henry Morley’s exhaustive Jerome Cardan: the life of Girolamo Cardano, of Milan, physician. That is partly because this biography, published in 1854, informed Alan Wykes’s Doctor Cardano, Physician Extraordinary, the book that finally tipped me into dedicating time to getting to know the real Jerome.

Wykes says Morley’s book is ‘afflicted with Victorian turgidity’. I don’t agree, but I can see where he is coming from. Wykes’s book, published in 1969, is certainly not turgid — it is an entertaining and lucid tale, great company in front of a roaring fire, a single malt in hand. But it is also, as you’ll know by now, not to be trusted. That is not a condemnation, exactly. I have friends who could be described using the exact same phrasing and I would not be without any of them.

I also used a few other books on Jerome’s life and work which can be trusted. Let’s put them into chronological order:

JEROME CARDAN:
a biographical study
by William George Waters

Waters’ 1898 volume is essentially a distillation of Morley’s work (and also afflicted with ‘Victorian turgidity’, according to Wykes). There’s not much more to say about it, except to be thankful, in the light of Morley’s magnum opus, for its relative brevity.

CARDANO:
the gambling scholar
by Øystein Ore

‘An all but extinguished scientific luminary of 16th-century Italy shines again,’ gushed The New York Times on this book’s publication in 1953. ‘Briskly interesting to lay readers, sometimes scarcely falling short of being racy,’ said the New York Herald Tribune. Well, ‘racy’ perhaps meant something different back then, but it’s certainly interesting. Ore was a Norwegian mathematician. It’s not clear how he came to celebrate Jerome’s life in print but his dissection of Jerome’s work on probability is thorough and informative.

GIROLAMO CARDANO 1501-1576:
physician, natural philosopher, mathematician, astrologer, and interpreter of dreams
by Markus Fierz (translated by Helga Niman)

This biography was written by a Swiss mathematical physicist working from Jerome’s collected works, the Opera Omnia, in 1977. For a physicist, Fierz is wonderfully generous towards Cardano, giving him credit for his open-mindedness and appropriate use of astrology. I particularly like his assertion that ‘Cardano did not reject the Copernican theory completely.’

THE CLOCK AND THE MIRROR:
Girolamo Cardano and Renaissance medicine
by Nancy G Siraisi

We are in 1997 now — only twenty years ago! Siraisi’s book is primarily concerned with Jerome’s medical practice, how it fitted with the times, and how it compares with the work of today’s practitioners. There is much to enjoy here, and Siraisi is generally impressed by Jerome’s insight. She highlights his understanding that men could be rendered impotent by a curse, as long as they believed in it, and that magical remedies for impotence worked simply because they ‘substituted hope for the patient’s despair’. Siraisi’s view is that Cardano was a level-headed investigator of the physician’s art. ‘He repeatedly urged, in a manner highly unusual in the sixteenth century … that the first thing to ask about a supposed marvel was not what had caused it but whether it had happened.’

CARDANO’S COSMOS:
the worlds and works of a Renaissance astrologer
by Anthony Grafton

Grafton’s book, published in 1999, offers deep insight into the human mind’s yearning for advice, however unreliable the source. My favourite part is the dissection of economics as the modern counterpart to astrology. ‘Like the economist, the astrologer generally found that the events did not match the prediction,’ Grafton says, ‘and like the economist, the astrologer normally received as a reward … a better job and a higher salary.’

There were sources other than books. It was a revelation and an utter joy to discover that my friend and colleague Professor Artur Ekert was also somewhat taken by Jerome. In 2008, Ekert wrote a short treatise, ‘Complex and Unpredictable Cardano’, laying out why his discovery of probability and complex numbers linked Jerome to quantum theory. Ekert is one of the inventors of quantum cryptography, the art of using the fundamental laws of physics to encrypt information. I feel that Jerome would, in many ways, rather have talked with him than with me.

Finally, two Jerome-free publications that have informed these discussions. First is John Gribbin’s In Search of Schrödinger’s Cat. This is quite simply a wonderful, measured, intelligent introduction to quantum theory. I’m not sure it has been surpassed, despite having been published way back in 1984. Second is Astrology Decoded: a step by step guide to learning astrology by Sue Merlyn Farebrother. Do I need to say that I don’t believe it? Well, that doesn’t actually matter. I liked its ambition. I think Jerome would approve, too.

That’s enough of the written word. I must mention a few people who have assisted me along the way. The staff of the British Library were unfailingly helpful. I have had equally helpful conversations with Ian Maclean, John Henry, Dario Tessicini, Alec Ryrie, Tom McLeish, Giles Gasper, Chris French, and Artur Ekert, among others. The generosity of the Fetzer Franklin Fund enabled me to travel to a gathering of quantum desperadoes in Vienna. I am grateful to Philip Voke, who entrusted Wykes’ papers to Reading Library, and generously pointed me towards them. I would also like to thank my friend Helen Bagnall for her encouragement to press on and finish what frequently looked like a doomed project.

Now to those whose sharp minds assisted the production of this book. Here, Artur Ekert merits another mention for his comments on an early draft. My agent, Patrick Walsh, his assistant, John Ash, and Scribe’s irrepressible Philip Gwyn Jones have all made invaluable suggestions concerning the manuscript. Molly Slight proved an invaluable copy editor, picking up all kinds of errors and omissions.

Jerome, who still inhabits my dreams on occasion, remains in splendid superposition as my chief critic and supporter. On his first reading of the manuscript, PGJ suggested I might be a little in love with Jerome. Perhaps. I do miss having him all to myself now, I must say.

—Michael Brooks, March 2017