The tentative and revisionary character of scientific knowledge is believed to play a central role in nature of science (NOS) studies by teachers, researchers, and curriculum developers. However, some educational researchers and scholars have recently expressed serious concerns about the view of tentativeness and change espoused in the science education literature claiming that it is simplistic, one-dimensional, inconsistent, irresponsibly vague, and self-contradictory. Despite these concerns, there are few detailed examples of how these types of problems manifest themselves in the science education literature and the difficulties they might pose for learners and other researchers. Accordingly, this article isolates and critically examines a single foundational proposition about the tentativeness of science made by leading NOS researchers. It is demonstrated that this generalization has some important inconsistencies and limitations that are problematic at the philosophical and instructional level. Throughout the article, it is argued that a logico-linguistic analysis of epistemic propositions made by researchers is desirable in NOS studies and that seemingly benign propositions can give rise to different viable, yet diametrically opposed, interpretive frameworks
