We investigate the impact of informal arguments on judgments about thought experiment cases in light of Deutsch and Cappelen’s mischaracterization view, which claims that philosophers’ case judgments are primarily based on arguments and not intuitions. If arguments had no influence on case judgments, this would seriously challenge whether they are, or should be, based on arguments at all—and not on other cognitive sources instead, such as intuition. In Experiment 1, we replicated Wysocki’s (Rev Philos Psychol 8(2):477–499, 2017) pioneering study on (...) a Gettier-style case, and we confirmed that the informal arguments used by him had no significant effect. However, we also included an improved argument for ascribing knowledge, which did have a significant effect even in Wysocki’s original design. We therefore followed up with Experiment 2 on three Gettier-style cases, where we used a more natural dialogical format for presenting both case descriptions and informal arguments. Overall, we found a clear impact of prima facie good pro and con arguments on case judgments. The issue of argument impact is thus no obstacle to arguing about thought experiments. (shrink)