Nature is nowhere rectangular: Galileo's Starry Messenger meets Matisse's Le Guignon: science and art each result from intense seeing. Evidence can be a beautiful thing

A colleague of Galileo, Federico Cesi, wrote that Galileo's thirty-eight hand-drawn images of sunspots "delight both by the wonder of the spectacle and the accuracy of expression." That is beautiful evidence.

Evidence that bears on questions of any complexity typically involves multiple forms of discourse. Evidence is evidence, whether words, numbers, images, diagrams, still or moving. The intellectual tasks remain constant regardless of the mode of evidence: to understand and to reason about the materials at hand, and to appraise their quality, relevance, and integrity. Science and art have in common intense seeing, the wide-eyed observing that generates empirical information.

In late 1690, Galileo constructed a telescope and soon "made more discoveries that changed the world than anyone has ever made before or since." (1) Sidereus Nuncius (The Starry Messenger), published in 1610, announced the discovery of craters on the moon, a multitude of stars beyond those few seen by unaided eyes, and the four satellites of Jupiter. More importantly, the book "told the learned community that a new age had begun and that the universe and the way in which it was studied would never be the same." (2) From then on, theories about the universe had to be tested against the visual evidence of empirical observation. This is the forever idea in Galileo's book. And so armchair speculation, parsing Aristotle and religious doctrine, and philosophizing were no longer good enough. Evidence became decisive in understanding Nature.

Sidereus Nuncius presents its evidence in seventy-eight images and drawings, all tightly integrated within their explanatory text, that cover thirty percent of the printed area in the book's sixty pages. A few days before the book was published in March 1610, Galileo added four new unnumbered pages, inserted between pages 16V and 17R. Half text and half image, these pages report the astounding discovery of vast numbers of stars far beyond those seen by unaided eyes. Reproduced on the next page, this triumph of scientific discovery and of information design depicts the visible stars of brighter magnitude seen by unaided eyes for centuries, as well as innumerable "invisible stars" now seen by telescope. Symbolizing the cosmic vastness, printed stars flow into the margins and then off the pages into an unbounded void, breaking out of the book's typographic grid (for Nature is nowhere rectangular) and breaking the limits of past knowledge.

Describing the innumerable stars, Galileo distinguishes between word and image in reasoning about celestial objects. Before 1610 astronomy had largely been verbal gymnastics, speculation, philosophizing, disputation. In contrast, these new telescope images are the direct, visible, decisive testimony of Nature herself. In the Latin text accompanying the stars scattered across the pages, Galileo makes the key link between empirical observation and credibility with the phrase "visible certainty," oculata certitudine. And that is the grand forever consequence of Sidereus Nuncius: from then on, all science, to be credible, had to be based on publicly displayed evidence of seeing and reasoning, and not merely on wordy arguments. Galileo wrote:

   What was observed by us in the third place is the nature or matter
   of the Milky Way itself, which, with the aid of the spyglass,
   may be observed so well that all the disputes that for so many
   generations have vexed philosophers are destroyed by visible
   certainty, and we are liberated from wordy arguments. For the
   Galaxy is nothing else than a congeries of innumerable stars
   distributed in clusters. To whatever region you direct your
   spyglass, an immense number of stars immediately offer themselves
   to view, of which very many appear rather large and very
   conspicuous but the multitude of small ones is truly unfathomable.

And since that milky luster, like whitish clouds, is seen not only in the Milky Way, but dispersed through the ether, many similarly colored patches shine weakly; if you direct a glass to any of them, you will meet with a dense crowd of stars. (3)

Accompanying Galileo's stars, we have reprinted a double-page spread from Henri Matisse's Poesies, one of the finest artists' books of the twentieth-century. Like Galileo's page layout in The Starry Messenger showing the innumerable stars, the Matisse drawings break out of the typographic grid. As Matisse wrote: "The design fills the unmargined page, for the design is not, as usual, massed toward the center, but radiating over the whole sheet. The problem was then to balance the two pages--one white, that of the etching, and one relatively black, that of the typography. I obtained my result by modifying my arabesque so that the attention of the spectator would be drawn again to the white page as much as to the promise of reading the text." This parallelism of Galileo and Matisse reflects the one deep communality of science and art: to show the results of intense seeing.