It is the essence of our approach that appearance and reality are quite distinct and the child is designed to discover reality via appearance. We take a rather brute force logical attitude toward making their relations explicit. In our formalism, both appearances of objects and physical objects will be represented as logical objects, i.e. as the values of variables and terms. In Quine's terminology, the ontology includes both appearances and objects. Our examples of appearances will mainly be visual appearances, because we understand them better than auditory, tactile or olfactory appearances.
Natural language is better at describing objects than appearances.
This is for two reasons. First, appearances are represented in thought by something like pointers to the appearance itself. Second, appearances are fleeting and can't be fully re-examined. Our robot's language of thought could use pointers to pictures, e.g. gifs. Suppose we did that.