Published online by Cambridge University Press: 26 September 2008
Between 1550 and 1650, the intellectual elite of Ashkenazic (German-and Yiddish-speaking) Jews, including rabbis such as Yom Tov Lipmann Heller (1578–1654), showed a marked interest in astronomy, and to a lesser degree in the natural sciences generally. This is one aspect of the assimilation of medieval Jewish rationalism by that group. Passages from Heller‘s writings show his familiarity with medieval and early modern Hebrew astronomical texts, and his belief that astronomy should be studied by all Jewish schoolboys. Heller‘s astronomical views were then influenced by the discoveries and debates of his period. Between 1614 and the 1630‘s, Heller moved from an Aristotelian to a Tychonic view of the nature of the celestial bodies. Inspired, furthermore, by the notion of a natural order subject to change, and basing himself on the exegesis of ancient rabbinic texts, Heller offered what we have termed” midrashic natural histories”: namely, a hypothesis concerning the development of a certain type of animal, and another concerning the dimming of the moon and its movement into a lower orbit.