 The Leibnizian principle that “there are never two things in nature which are exactly alike and in which it is impossible to find a difference that is internal or founded on an intrinsic denomination” is enunciated in the Monadology (G 6: 608), as well as in the Correspondence with Samuel Clarke (G 7: 372). Leibniz had abandoned his earlier view that two entities could be distinguished by place alone when he came to his view of real substances as infinitely complex and unique and space as ideal. Kant found the Principle arbitrary. To insist that any two objects presented to us in experience must be qualitatively different in some respect was, Kant said, to take appearances for intelligibilia (KRV A 264/B320). We cannot have two concepts — concepts of two things — that are alike in all their specifications, but we can certainly have two empirical objects that are exactly alike. Why should we not be able to imagine two identical water droplets? (20:280). It is sufficient for there to be two that they present themselves to us (veridically) in our visual space as two. Leibniz’s blunder on this score was, for Kant, an indication that Leibniz had failed to grasp an important feature of sensory experience, namely that it, unlike thought in general, is always spatial.