This is the other side of the 'scientific evidence' debate. I have no doubt that the evience has led Paul Kirschner to the conclusions he has reached (just as it has let the also-mentioned John Hattie to reach his conclusions). The question is: can we trust the evidence, and can we trust the inference that leads to the conclusion? For Kirschner, the answer is clear. "Cognitive load is about how our cognitive architecture affects how we learn and how this interacts with instruction. There are possibly two thousand scientific articles that show that the theory generally holds."