Dream_weaver “Doesn’t the conceptual level operate from the perceptual level?” Not necessary. Think about “dog”-if you are a dog -owner you’d think about your own dog. If not, you may imagine some animal which has essential features of dog, but doesn’t represent any specific perceptual dog. You can even imagine non-existent animal-like unicorn or flying dragon, or an animal you never saw before, only read its description. Think about higher concepts like capitalism, altruism etc… You don’t have any equivalents of such a concepts on perceptual level. Although it is true that concepts are implied in perception, we usually operate with explicit concepts,that is-words."With the exception of proper names, every word we use is a concept that stands for an unlimited number of concretes of a certain kind". The proper function of concepts is an expanding grasp of existence because concept includes all entities which belong to the same species (all dogs) or genus ( all animals) or existence ( all existents).
In Ayn Rand words:
"A concept is a mental integration of two or more units which are isolated by a process of abstraction and united by a specific definition. By organizing his perceptual material into concepts, and his concepts into wider and still wider concepts, man is able to grasp and retain, to identify and integrate an unlimited amount of knowledge, a knowledge extending beyond the immediate concretes of any given, immediate moment. In any given moment, concepts enable man to hold in the focus of his conscious awareness much more than his purely perceptual capacity would permit. The range of man’s perceptual awareness—the number of percepts he can deal with at any one time—is limited…He cannot visualize a hundred trees or a distance of ten light-years. It is only his conceptual faculty that makes it possible for him to deal with knowledge of that kind."
“The Psycho-Epistemology of Art,”
Since we cannot operate on perceptual level, the situation is quite opposite to that which you’ve described. Even by referring to concretes we use concepts. Suppose you see a birch tree and this is a percept. But when you refer to it you refer to birch tree, not to this particular birch tree you saw. It will take hours and maybe days to describe the particular birch tree in all details which distinguish it from all other birch trees and even so you won’t be able to do so without using concepts. Even if you describe it ostensibly-just point out on it and say-that what I mean, you are using at least 4 concepts.