Speaking of Sunspots: Oral Culture in an Early Modern Scientific Exchange

"The sun will also give signs; who would dare call it a liar?"¹ So the German Jesuit astronomer Christoph Scheiner concluded in an adaptation of verses drawn from the first book of Virgil's Georgics,² the third of his Three Letters on the sunspots in December 1611. The supposition that the solar body disbursed a legible and even meaningful set of signs through the medium of the random markings newly discovered on its surface was persistent in the early years of the debate over the phenomena, characterized for the first time in the Latin West by the simultaneous scrutiny and publication of a number of observations. Such confidence, shared by otherwise antagonistic observers, depended upon the telescope through which the spots were projected and drawn, and upon the engraving and printing techniques used to disseminate the observations and accompanying texts, for both instruments appeared to promise an accuracy, uniformity, immediacy, and level of detail almost entirely absent from the meager and all too malleable sunspot records of the past.³ It is no accident, then, that a variety of observers described the projection of the spots onto the page as printing, as if the optical procedure were a kind of transfer from a single manuscript to a limitless number of identical copies distributed all over the globe and differing, at most, in size or format.⁴

But while the comparison of projections and printing—rendered all the more plausible by the reliance in Latin and Italian on the verbs incidere and stampare—suggests a world characterized by the circulation of fixed texts and stable images, and by the exchange of mechanically produced and infinitely reproducible information, the conflict between Christoph Scheiner and Galileo Galilei also abounds in allusions to the more evanescent realm of oral culture. Apart from their initial reliance on the metaphor of printing, both writers allude much more frequently to the ways in which languages are spoken, to the aural acquisition of knowledge, to the specialized vocabularies of entire communities of speakers quite remote from the original debate, and to the public discussion of the sunspots.

In this essay I will address the context of the happy fiction that everyone was speaking of sunspots—more broadly, the relationship of an oral culture to a written one—but let me first offer a brief overview of the historical context of the quarrel between Galileo and Scheiner. Apart from Theophrastus's and Virgil's allusions to sunspots as temporary harbingers of rain in the third and first centuries BC, a cluster of ninth-century references to the anomalous solar activity associated with the recent death of Charlemagne, and a few scattered mentions of a spotted sun in chronicles of the twelfth, thirteenth, and fifteenth centuries, there was in the Latin West neither a conceptual rubric nor anything approaching an established observational record for such phenomena. It is not surprising to find that both those who interpreted earlier reports, such as Avicenna in the eleventh century or Averroës in the twelfth, and those who observed the spots themselves, such as the Florentine poet Raffaello Gualterotti in 1604 and Johannes Kepler in 1607, assumed that planetary transits provided the explanation. Though neither Galileo nor Scheiner was the first to undertake telescopic scrutiny of the sunspots —the Englishman Thomas Harriot did so in December 1610, and the Frisian David Fabricius made the first printed reference to the phenomena in the summer of 1611—the absence of an established observational tradition and the seeming absurdity of a maculate sun made the debate particularly volatile.⁵

Writing under the pseudonym of "Apelles hiding behind the canvas" so as not to embarrass the Society of Jesus,⁶ Christoph Scheiner rushed into print with the suggestion that the spots surrounding the sun did not impinge on the purity of that remote body, and that they were actually stars traveling at some small distance from it. He struggled to maintain this position over the course of six letters published in late 1611 and 1612 by Marcus Welser, an obliging humanist with a private press...