The dual-process model of cognition but most especially its reflective component, system 2 processing, shows strong conceptual links with critical thinking. In fact, the salient characteristics of system 2 processing are so strikingly close to that of critical thinking, that it is tempting to claim that critical thinking is system 2 processing, no more and no less. In this article, I consider the two sides of that claim: Does critical thinking always require system 2 processing? And does system 2 processing always result in critical thinking? I argue that it is plausible and helpful to consider that critical thinking requires system 2 processing. In particular, this assumption can provide interesting insights and benchmarks for critical thinking education. On the other hand, I show that system 2 processing can result in a range of outcomes which are either contradictory with critical thinking, or of debatable social desirability—which suggests that there is more to critical thinking than mere system 2 processing, and more to system 2 processing than just critical thinking.