Assessing uncertainty in the geological understanding of the subsurface, as with many areas of applied science, demands seeking out and valuing alternative interpretations. But how inclusive are we collectively in promoting and valuing diverse interpretations? We explore this question using a parable drawn from the history of earth sciences—examining the conduct of the Continental Drift Debate of the 1920s. Aggressive, intemperate language by leading North America geologists devalued interpretations and the competence of geologists who proposed a tectonically mobile Earth. Our contention is that this reinforced groupthink that rejected alternative hypotheses and observations that conflicted with their own explanations, and argue that this in turn inhibited research on global tectonics for the decades that followed. We explore how increasing the diversity of participants in scientific debates along with treating diverse views with respect and tolerance could avoid these outcomes.