 Dellsén (2016, 2018b) has formulated the noetic account of scientific progress as increasing understanding. Using objectual understanding instead of understanding-why, he characterizes understanding in terms of “grasping how to correctly explain and predict aspects of a given target”. Against Bird (2007), who takes understanding to be a species of knowledge of causes, Dellsén argues that understanding does not require the scientists to have justification for, or even belief in, the explanations or predictions they propose. Still, understanding is a matter of degree. Thus, there are increases in scientific understanding without accumulation of scientific knowledge (e.g. Einstein’s explanation of Brownian motion in terms of the kinetic theory of heat) and accumulation of scientific knowledge without increases in understanding (e.g. knowledge about random experimental outcomes or spurious statistical correlations). The latter thesis is easy to accept, especially if explanation needs laws, but on the other hand the epistemic and truthlikeness approaches could agree that the collection of new important data may constitute scientific progress. The possibility of “quasi-factive” understanding by means of idealized theories (a common feature with the verisimilitudinarian approach) is taken to be an advantage of the noetic account. Park (2017) has challenged Dellsén’s conclusions against the epistemic definition. He argues that scientific understanding involves beliefs that the explained phenomena are real and the confirmed predictions are true. He also argues that Wegener’s continental drift theory, which was not supported by available evidence, was progressive, since it paved the way for the later theory of plate tectonics in the 1960s. Dellsén (2018a) questions Park’s arguments by rejecting the “means-end thesis”, i.e., one should make the crucial distinction between cognitive and non-cognitive scientific progress and likewise distinguish episodes that constitute and promote scientific progress.