Numerous societal issues, from climate change to pandemics, require public engagement with scientific research. Such engagement reveals challenges that can arise when expertsExperts communicate with laypeople. One of the most common frameworks for studying these communicative interactions is the deficit modelDeficit models of science communicationScience communication, which holds that laypeople lack scientific knowledge and/or positive attitudes towards science, and that imparting knowledge will fill knowledge gaps, lead to desirable attitude/behavior changes, and increase trustTrust in science. Section 6.2 introduces the deficit modelDeficit models in more detail and shows that adhering to this model often fails to achieve its aims, which motivates the main questionQuestions of this chapter: how can Ludwik Fleck’s theory of thinking collectivesThinking collectives address the persistent problemProblems of deficit approaches in science communicationScience communication? I suggest that it can do so by exposing the deficit modelDeficit models’s implicit assumption of an expert-lay divide. Accordingly, Sect. 6.3 lays out Fleck’s theory and Sect. 6.4 contrasts it with contemporary debates about science communicationScience communication. Following this descriptive work, Sect. 6.5 draws on Fleck’s ideas to make four concrete suggestions for further questioning the expert-lay divide.