Abstract: This dissertation focuses on the landmark Machine Art exhibit held at the Museum of Modern Art in New York during the spring of 1934. The exhibit displayed over 400 objects of mechanized mass-production: including airplane propellers, ball bearings, pots, pans, and Petri dishes. Beginning with the seemingly simple observation that Machine Art consisted entirely of three-dimensional objects, I maintain that materiality and thingness—the objects' brute, physical presence—was fundamental to MoMA's formalist aesthetics both in this show and for modernism more generally. Four chapters address different aspects of thingness and materiality as they pertain to Machine Art and a series of supporting case studies: temporality, value, production, and experience. In Chapter 1, “The More Things Change,” I consider how Machine Art's things provided museumgoers with a tangible way to adjust to the rapid pace of Machine Age modernization. In Chapter 2, “In Form We Trust,” I examine how MoMA's absolute principles of form, beauty, and value circulated in Machine Art as a sort of aesthetic gold standard: a reliable measure of artistic worth for all things, and a conservative hedge against the era's rampant change and volatile unpredictability. In Chapter 3, “Some Assembly Required,” I argue that Machine Art ironically co-opted the contemporary discourse of direct carving in sculpture (itself motivated by anxieties over mechanization), only in order to celebrate the simple forms of mass-production. In Chapter 4, “The Eye of the Beholder,” I focus my attention on the popular ballot MoMA conducted in conjunction with the Manhattan installation of Machine Art: a story which serves to illustrate the complexities and contingencies involved in the practice of evaluation, in spite of all MoMA's efforts to the contrary. Machine Art's aesthetic proposition demonstrates a more ambivalent—and ultimately more conservative—attitude toward both modernism and early twentieth-century consumer capitalism than has heretofore been understood. Using objects to appropriate the discourse of sculpture and to turn abstract aesthetic ideals into concrete forms, with Machine Art MoMA offered an ideology of modernism premised on the conservative values of authenticity, transcendence, and timelessness.