The distinction between conceptual and nonconceptual contents clearly has consequences for the configuration of the world of humans as well as for the possibility of attributing thought, in the strict sense, to systems and nonhuman organisms. With the aim of clarifying such a distinction, the following paper poses a basic notion of mental state and, especially, a clear definition of concept, along with the fundamental features of the states in which concepts occur. The conclusion of the paper is that we have good and enough reasons to speak of conceptual and nonconceptual contents instead of more-or-less conceptual concepts. It means that there is a distinction of kind, not of degree, between both contents.