When I first heard that Philip Glass was writing an opera on Johannes Kepler (1571-1630) for Linz, it was clear that the opera was designed to honor one of this Austrian city's most famous residents. I further presumed that Glass would entwine Kepler's fight for scientific truth with his mother's trial for witchcraft. But that turned out not to be Glass's intent. Kepler's mother is never mentioned in this 2009 opera. Other issues are at stake here.
As in his first trio of "great men" works, this is a portrait opera, not a narrative drama. There is of course a narrative thread through the opera, though in word and mood only, not in action. This kind of drama, with all talk and no action, is very hard to stage. Indeed, when it was performed in New York City, it was given as a concert opera. Perhaps oratorio would be a better word. The Kepler character's alternation with the chorus and an ensemble of soloists recalls religious services in the call and response or antiphonal format. In turn these sections at various points alternate with choral settings of poems by Andreas Gryphius (1616-64). The oratorio-like format works perfectly as a means of getting into the mind of a person, like many others of his time, who understood his scientific inquiry as a contribution both to knowledge about and to the glory of his God: the more he could learn about the workings of nature, especially planetary orbits, the more he would understand about nature's Creator, and the closer he would feel to his God.
In the libretto by Martina Winkel, Kepler is featured in eight of the opera's segments, providing a succinct summary of his achievements, only some of which we might today consider "scientific." In fact, Kepler engaged as much in astrology as astronomy, for often relied on astrological positions for income and government posts. These opera texts make interesting reading on their own, but I confess regular recourse to Wikipedia for fleshing out the issues. For what its worth, here is a summary:
1. "Questions 1": Kepler announces his quest to understand the mathematics of the created universe: basically the rules by which God plays.
2. "Polyhedrons": Kepler produces his model of planetary orbits as spheres circumscribing a variety of nested polyhedrons. Kepler's satisfaction at arriving at this intricate solution is underscored by his belief that he has seen into the mind of God.
3. "Genesis": As the chorus sings the account of creation from Genesis, Kepler rejects it as theology, unsubstantiated by laws of optics or mathematics or by the astronomical observations that he is compiling.
4. "Celestial Physics": Kepler explains his application of mathematics to astronomical physics to create more complete science capable of understanding the physical laws that maintain celestial bodies in orbit. Kepler also expresses his view that the universe is an image of God.
5. "Questions 2": Kepler recounts his attempts to find the same mathematical laws expressed in other natural forms, an example of which is his study of the geometry of snowflakes.
6. "On Astrology": Two aspects of Kepler's deep engagement with astrology are explored. First, Kepler explains that he has prepared an astrological reading based on the moment he believes he was conceived, giving the chorus an opportunity to compare his belligerent and abrasive personality to a ravenous dog. To this Kepler responds with a list of scientists that he hated, that hated him, or both. Second, Kepler explains his theory that the connection between celestial movements and the actions of humans is the soul.
7. "Hypotheses": This section represents the culmination of Kepler's inquiry into the mathematics of planetary orbits, using data from Tycho's detailed observations of Mars. Kepler first tests the hypothesis of an oval orbit and then realizes that an elliptical orbit better fits the data for Mars, a conclusion he then applies to other planets. By this means he also suggests a theory of the relation of force to distance from the sun. When Kepler combines these achievements with a theory of celestial musical harmony, the chorus expresses his religious fervor in an exquisite hymn-like setting of a prayer Kepler published in Harmonices Mundi (1619). This prayer is derived in part from Psalms 146 and 148 but interpolates praise for celestial harmonies and for human abilities to discover the laws of creation.
8. "Ephemerides": Kepler's life ended with family disruption during the Thirty Years War (1618-48). His description of the depredations of warfare in this section, following as it does his inquiry into the laws of nature, suggests a counterpoint in human degradation of those laws. The Gryphius poem that immediately precedes this section deals with the same topic. The lives of Gryphius and Kepler overlapped precisely during this conflict.
Beyond the eight examinations of Kepler's theories and the interpolated Gryphius poems is a setting of Kepler's epitaph. This setting appears in somewhat different form as both the prologue and epilogue to the opera. The repetition of the beginning at the end gives the opera a circularity or cyclicity that reinforces Kepler's obsession with planetary orbits and the advances he made in their study.
Musically, it has been said that in Kepler, Philip Glass is returning to his roots. Though this is true enough in terms of the reworking of the portrait opera format he explored with early works like Satyagraha (1980), it is not an apt description of the musical style. Though the ritualistic format of the work represents a profound contrast to the two lyric dramas that preceded it (Waiting for the Barbarians and Appomattox), musically Kepler represents a continuation of Glass's exploration of orchestral color and development of long "spun-out" melodies that are quite different from his early style. As to the performance, long-time Glass collaborator Dennis Russell Davies can be counted on to achieve the highest standards.