Logic enables us to avoid and correct such mistakes at the conceptual level. Although logic requires that our concepts be properly grounded in perception, we cannot use logical methodology to manage our perceptual and sensory processes, since these are automatic and involuntary. Logic's principal function is to show us how to perform valid integrations of concepts, to build a conceptual hierarchy properly. In addition, logic enables us to check out a concept that we have already formed, to trace it back down the hierarchy by a process known as "reduction" (). Thus we can relate our most abstract concepts to concrete experiences of reality.