Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

First Advisor

Christopher Braider

Second Advisor

Stéphane Lojkine

Third Advisor

Masano Yamashita

Fourth Advisor

Kieran Murphy

Fifth Advisor

Katherine Eggert


My dissertation focuses on the role that thought experiment played in early modern astronomy. More specifically, I examine the intersecting problems posed for physics and astronomy in tandem by the Copernican Revolution: the problem of the unity of nature; the problems of observation surrounding the telescope; the phenomenon of relative motion as a key to reinterpreting observational data; and the problem of the plurality of worlds as at once a logical consequence and a symbol of the ways in which the “New Science” of seventeenth-century and eighteenth-century Copernicanism challenged traditional cosmology within the works of the observers Galileo Galilei and Johannes Kepler, which I present in the first section, and the French popularizers René Descartes, Cyrano de Bergerac, Voltaire, and the marquise du Châtelet in the second. My particular focus is on the thought experiment in the physical sense of the term and the various forms of fiction associated with it, stemming from my exploration of the limits natural philosophers and astronomers encountered in their efforts to make sense of their observational data—limits imposed by their increasing awareness of the optical as well as technical deficiencies of the observational instruments available to them, as by the lamentable fact that they lacked the means to make the voyages necessary to perform direct empirical inspection of extraterrestrial “worlds.” Thought experiment thus emerged as the only means of performing the kind of experiments they believed were needed to refine as well as settle the relational issues the Copernican Revolution raised.

Available for download on Thursday, January 27, 2022