A science museum exhibition about human health contains an exhibit that minimizes health impacts of air pollution. Relevant details, such as the full range of health risks; fossil fuel combustion; air quality statutes (and the local electrical utility’s violations of these statues), are omitted, while end users of electricity are blamed. The exhibit accomplishes this, not through outright falsification, but through selected “alternative facts” that change the focus and imply misleading alternate explanations. Using two classical rhetorical concepts (the practical syllogism and the enthymeme) allows for the surfacing of missing evidence and unstated directives underlying multimodal rhetoric. By stating multimedia arguments syllogistically, a technique is proposed for revealing hidden political sub-texts from beneath a putatively disinterested presentation of facts. The piece should be of interest to researchers, message designers and policy makers interested in the rhetoric of science, ecology, health and museums.