The Worlds and Works of a Renaissance Astrologer

By Anthony Grafton

Harvard Univ. 284 pp. $35

More years ago than I like to remember, I spent eight or nine pleasant months reading 40 or so of the world's great autobiographies. Besides the obvious classics, such as the confessions of Augustine and Rousseau, the book I most enjoyed was Girolamo Cardano's The Book of My Life. Equally acclaimed as a mathematician, astrologer, physician and gambler, Cardano (1501-1576) -- a multi-talented guy even by Renaissance standards -- organized his life story by topic. So, for example, he offered concise chapters on "Those Things in Which I Take Pleasure," "My Manner of Walking and of Thinking" and, most appealing to any pessimist, "Things in Which I Feel I Have Failed."

Back then, what struck me especially were Cardano's surprisingly modern frankness and his Wordsworthian joy in homely details. He openly confesses to having been sexually impotent for 10 years, between the awkward ages of 21 and 31. He talks about his lasting affection for cats, puppies and little birds. He even tells us that he has lots of trouble finding well-fitting shoes. And almost in passing, this highly engaging, somewhat prickly polymath reveals that through much of his life he has been accompanied by an attendant spirit or daemon.

I had hoped that Cardano's Cosmos would be a leisurely and capacious biography of this Italian counterpart of the celebrated Elizabethan magus John Dee (the two met at least once), a hefty companion to Anthony Grafton's earlier life of the great Latin scholar Joseph Scaliger. After all, the author of The Secrets of Eternity (alas, never completed) -- not to mention a standard work on games of chance, a study of teeth, and the marvelously titled On Subtlety -- certainly deserves as much. But this is not quite that dream book. Instead Grafton uses Cardano's career to examine the place and character of astrology during the 16th century.

Now a modern reader might easily expect the Dodge Professor of History at Princeton to be rather lordly and scornful of this classic pseudo-science. How, after all, could any intelligent man believe that at our birth the heavens proclaim our characters or that the stars chart the course of our destinies? But Grafton almost humbly seeks to understand how astrology once operated as a social phenomenon and in the end discovers much to respect.

Cardano and other astrologers, he concludes, "saw themselves as offering their readers a sharp-edged set of tools with which to free themselves from slavery to external circumstances -- not by learning to see around them but by schooling themselves to predict them. They felt certain that knowledge of the future would enhance, not diminish, the mastery of the self; excess passion could be contained more easily, after all, by those who saw the occasions for it coming, in advance. Astrology, like philosophy, offered a discipline of life -- and one adapted to the needs of the man who recognized himself as human and knew that his happiness was inextricably bound up with the fates of his body, his household, and his nation."

In particular, Grafton emphasizes that collections of printed genitures -- the horoscopes based on a person's birth date and time -- might possess multiple social and literary functions: At various points he likens these astrological write-ups, usually of illustrious figures (either living or dead), to gossip columns, newsletters, character analyses, political dossiers and Montaigne-like essays. Cardano displayed a virtuoso's flair for varying his style when creating these star-driven mini-biographies. "Like a nineteenth century German composer writing lieder, he associated freely, changed moods and forms with startling speed. He found himself able to attack an incredibly diverse range of themes and incidents, while remaining within the boundaries of a single form." Thus, for all its reliance on tables and mathematical calculations, Renaissance astrology was at its best a deeply humane art. And a fallible one. "The human intellect," as Cardano noted, "was simply too weak to read every detail written in the stars." Horoscope interpretation, adds Grafton, "required an inexpressibly complex, partly intuitive balancing of factors, a process in which errors and revisions were inevitable." No one expected astrology to be an exact pseudo-science.

For ordinary readers, Cardano's Cosmos provides the pleasures characteristic of Anthony Grafton's other books devoted to the intellectual history of early modern Europe: As in Defenders of the Text and New Worlds, Ancient Texts, we are regaled with donnish anecdotes and high-table factoids. In 1557 Cardano "became the object of the most savage book review in the bitter annals of literary invective. Julius Caesar Scaliger . . . devoted more than nine hundred quarto pages to refuting one of Cardano's books, On Subtlety." Grafton adds that this may be "the only book review ever known to undergo transformation into a textbook." The wealthy merchant banker Anton Fugger "used a scryer with a crystal ball to keep an eye on what his partners in cities far from Augsburg were up to." Pope Paul II "on 20 July 1471 . . . slept with a young man and was strangled in the act by demons." Georg Helmstetter of Heidelberg was the historical Dr. Faustus, and Richard Bruarne, "an Oxford man . . . became provost of Eton after being deposed for immorality from the chair of Hebrew at his alma mater."

And as one might expect from the author of The Footnote, Grafton's references are as inviting as his main text. In more than 50 pages of end-notes, the curious will learn about such marvel-filled works as Frances Yates's The Art of Memory, D.P. Walker's Spiritual and Demonic Magic from Ficino to Campanella , D.C. Allen's Mysteriously Meant and P. Brind'Amour's Nostradamus astrophile -- "the best informed and most technically competent study of an astrological practitioner of the Renaissance." Beyond doubt, Grafton is now our leading guide to the history of humane letters and scholarship between the Renaissance and the rise of Romanticism.

In the end, Cardano's cosmos is nothing less than a world of wonders, one in which -- to use words underlined by John Dee in an astrological text by Synesius -- "Everything is signified by everything, since all things in the one great animal of the world are related, and these are like letters of every shape, signed in the universe as in a book, some Phoenician, some Egyptian, some Assyrian. The wise man reads them." Girolamo Cardano read them as well as anyone. And in his way so does Anthony Grafton. He shows us that 16th-century thinkers found in astrology much of what we now look for in psychology, political theory, moral philosophy and economics -- "fundamental tools for analyzing and controlling" our societies and ourselves.

Michael Dirda's e-mail address is

Excerpt: The Astrologer as Empiricist

Anatomy lessons in the sixteenth century were public events, held in theaters which provided a dramatic setting, often attended by grandees who had no professional interest in medicine, and regularly made more entertaining by the students, who grouped themselves into gangs and loudly urged their professors to debate with one another.

Cardano recalled with pleasure that every public anatomy of a nobleman which he had attended while at Bologna, from 1562 to 1570, had turned into a ritual of humiliation for his numerous critics. Time and again, the surgeon's knife laid bare undeniable facts that confirmed Cardano's unexpected but infallible conjectures. Medicine, like astrology, both worked wonders and revealed them to be the results of natural laws previously unknown. . . .

Cardano drew up horoscopes for some of his patients -- himself, for example, and Archbishop Hamilton -- and for other medical men. He also argued, in a long passage of his commentary on Ptolemy, that one could sometimes use the movements of the planets to explain the onset and course of a disease, day by day. He even suggested that one could interrogate the heavens about the sex of a pregnant woman's unborn baby. In the course of the same text -- a short treatment of the sort of catarchic, short-term astrology widely practiced by contemporary medical men in England -- he asserted, as forcefully as in any other passage of his work, the superiority of astral to other forms of knowing the future. "For the predictions of astrologers, when made using the rules laid down in this book, are far more solid than the knowledge of the doctors of our time about disease: for the account of astrology given here is extremely careful, while medicine is handled with great negligence." But elsewhere in the same large book that included this work -- the commentary on Ptolemy which Cardano himself identified as his crowning achievement in astrology -- he admitted that medicine, though epistemologically less profound than astrology, was practically superior to it, and that medical men enjoyed a far better reputation with the public than astrologers.

-- From Cardano's Cosmos