Scientific Understanding, Fictional Understanding, and Scientific Progress

The epistemic account and the noetic account hold that the essence of scientific progress is the increase in knowledge and understanding, respectively. Dellsen (J Gen Philos Sci 49(3):451-459, 2018) criticizes the epistemic account (Park in J Gen Philos Sci 48(4):569-579, 2017a) and defends the noetic account (Dellsen in Stud Hist Philos Sci 56(72):82, 2016). I argue that Dellsen's criticisms against the epistemic account fail, and that his notion of understanding, which he claims requires neither belief nor justification, cannot explain scientific progress, although it can explain fictional progress in science-fiction.