  The fifth group involves epistemology; they concern primarily how we have access to categories, that is, how we get to know them and under what conditions. Although this is not a widespread topic of discussion in the Early Middle Ages, later on there are various attempts to determine the number and identity of the categories and the basis on which this determination can be carried out. These attempts, and the assumptions which guide them, are closely related to an important issue for the Middle Ages in general that becomes critical toward its end: the relation of language, thought, and reality, or as it is also put, between signifying, thinking, and being, or between words, concepts, and things. Some think the relation is isomorphic, whereas others disagree.