The concept of “objective,” which applies as a norm to all rational cognition, has its roots in the theory of concepts. “Objectivity” arises because concepts are formed by a specific process and, as a result, bear a specific kind of relationship to reality.
The conceptual faculty is an instrument that reduces units by omitting measurements. Or: concepts are a human method—of integrating perceptual data. Or: concepts are a device of our consciousness—to deal with existents. All these formulations point to a crucial fact. Concepts do not pertain to consciousness alone or to existence alone; they are products of a specific kind of relationship between the two. Abstractions are products of man’s faculty of cognition and would not exist without it. But a faculty of cognition is concerned to grasp reality and must, therefore, adhere to reality.
On the one hand, there is a uniquely human contribution to the conceptual level of awareness, …
Read the rest in Objectivism: The Philosophy of Ayn Rand.