Johannes Kepler and the Pythagoreans

The early modern Republic of Letters had a complicated relationship with novelty. The period witnessed vast upheavals across the social and intellectual landscape, yet novelty was viewed with great suspicion, perhaps unsurprisingly, given all the turmoil. Purveyors of novelty were morally suspect, vain or seditious, or both. Sixteenth century authors rarely presented their work as new. Instead, when they put forth controversial doctrines, they cast them as ancient. If they could not plausibly trace their ideas to some snippet of Aristotle or Galen, then they appealed to figures considered even more antique: Moses, Zoroaster, Hermes Trimegistus, Hippocrates, Pythagoras. In doing so, they exercised preemptive self-defense, but it would be unfair to suggest that their motive was only a matter of camouflage or of ginning up sales in a competitive book market. Kepler’s work, for example, basks in the thrill of rediscovery, of connecting with great figures in the far-away past, figures who stood closer to creation, to the divine, to universal truth. The paradigm of rediscovery encouraged a hermeneutical attention to continuity and concealment. It also implied a certain historical template, wherein truth gave way to periods of confusion and portent, then to redemption and clarity. Such a template was at work, for instance, when exegetes mined the Old Testament for echoes of Christ’s birth and ministry. If most sixteenth century writers would have subscribed to a general, Christian-eschatological view of history, there remained within that framework room for cycles of collapse and restoration, such as Proclus described, concurring with Aristotle that “the sciences did not arise for the first time among us or among the men of whom we know, but at countless other cycles in the past they have appeared and vanished and will do so in the future.” The above considerations set the stage for Kepler’s use of the Timaeus. Of course, he appealed to the work as an example of mathematical natural philosophy. But it meant much more. Its interest, beauty, and authority drew from an ancient tradition beginning with the first Pythagoreans, passing through Plato, to Euclid and Proclus, and eventually to Copernicus. Kepler’s reception of the Timaeus as a Pythagorean text was not unique. Plato’s Renaissance translator and commentator, Marsilio Ficino, had endorsed the fundamentally Pythagorean lineage of Platonic philosophy. And as Kepler would, Ficino read the Neopythagorean philosophy of late antiquity back into the earlier Pythagorean tradition. Yet perhaps no author of early modernity gave such full expression to what the Pythagorean could mean as a mathematical inquiry into nature and the divine. Kepler, as early as his first book, the Mysterium cosmographicum (1596), saw himself at the summit of this mathematical tradition.