We can model reality, but we can’t understand what it is. The problem is that “what it is” has two aspects depending on whether we assume that classes aren’t real or that they are real, traditionally called nominalism and realism, respectively.
Nominalism (ie, assuming that classes aren’t real) leads to the conclusion that reality is ambiguous, whereas realism (ie, assuming that classes are real) leads to a pointer. The former can be interpreted simply as that everything has at least two aspects, but how can the latter be interpreted?
Well, digging deeper in this matter, we can understand that a pointer also has two aspects: the pointer itself and what it points at. So, how can this fact be interpreted? A hint to the solution is that these aspects are the same aspects as an error has: it is an error and it points at a possible solution. This comparison leads us to the interpretation of the pointer as an error, or, now climbing up from the hole, that realism leads to error. It means that we can interpret realism (ie, assuming that classes are real) as leading to error. (Examples of this error are, by the way, what cladists call “the tree of life” and what particle physics calls “Higgs particle”, none of which thus can be found.)
In summary, we can’t understand what reality is, because none of the alternative ways to such understanding that are given can lead to understanding, sorry to say. We thus have to conclude that we, unfortunately, simply can’t understand what reality is. (Instead, I would like to cite the Buddhist saying: give up, give up, give up.)