When considering the difference between something and the essence of something, Aristotle seems undecided as to whether this difference is discerned by different capacities of the psyche, or by the same capacity in different relations (On the Soul, 429b, 10-23). Proceeding from the recogni-tion that the state of affairs at issue is such that there are many cases in which there is indeed a difference between something, e.g., magnitude, water, flesh, straight, and its essence, Aristotle finds in the difference or differences at issue a reference to the psyche's capacity to discern the terms of this difference.