In the section of the Critique of Pure Reason entitled The Amphiboly of Concepts of Reflection Kant writes:Suppose that an object is exhibited to us repeatedly but always with the same intrinsic determinations . In that case, if the object counts as object of pure understanding then it is always the same object, and is not many but only one thing . But if the object is appearance, then comparison of concepts does not matter at all; rather, however much everything (...) regarding these concepts may be the same, yet the difference of locations of these appearances at the same time is a sufficient basis for the numerical difference of the object itself. Thus in the case of two drops of water we can abstract completely from all intrinsic difference , and their being intuited simultaneously in different locations is enough for considering them to be numerically different. (shrink)