James Griesemer’s paper “Material Models in Biology” was part of a Philosophy of Science Association symposium at the biennial meeting in 1990, titled “Biology: The Non-Propositional Side.” Interest in biology’s nonpropositional side derived from broader philosophical concerns over past decades about the adequacy of the logical empiricist account of science. Logical empiricists treated nonpropositional aspects of science—such as metaphors, analogies, and visualizations—as cognitively meaningless and therefore eliminable or reducible to propositional aspects. Griesemer sought instead to explore connections between propositional and nonpropositional aspects of scientific theorizing with the help of three case studies: Grinnell’s remnant models of faunas, Wright’s introduction of path analysis, and Weismannism’s role in the generalization of evolutionary theory. Griesemer’s emphasis on the materiality of models has been influential in post-logical-empiricist work on models and theories in philosophy of science. Griesemer’s attention to scientific practice has fostered productive interdisciplinary collaborations that have enriched science studies more broadly.