  Unfortunately, Leibniz's reasons for drawing these consequences are not in all cases obvious. Why should PII follow from the complete individual concept account of substance? If we consider the CIC as that which allows us to pick out and individuate any individual substance from an infinity of substances, then we realize that, if the individual concepts of two substances, a and b, do not allow us (or God) to distinguish the one from the other, then their individual concepts are not complete. That is, there must always be a reason, found within the complete individual concept of substances and issuing from the free decree of God, that a is discernible from b. And this fact points to another important fact about the interpretation suggested above: it is not only the case that each substance has a complete individual concept–the essence of the substance as it exists in the divine mind–but for every essence or complete individual concept there is one and only one substance in a world. (The argument here is essentially that which was given above in the section describing the relation between PSR and PII; namely, what reason could God have had for instantiating two substances with identical CICs?) Further, why should it be the case that substances can only arise naturally in God's creation of the world and end in his annihilation? If one takes quite literally Leibniz's claim that the CIC contains within it all predicates true of the substance past, present, and future, then one might be able to say that this must include truths extending back to the creation and forward either infinitely or to the end of time. This argument might be somewhat weak in itself, but it certainly would seem to follow from Leibniz's logical notion of substance and one of the other consequences, namely, that each substance is a mirror of the entire universe. If this is the case, then a substance, insofar as it is a mirror of the entire universe, must have within its complete individual concept predicates that extend back to creation and forward in time. At first glance, it is also not readily apparent merely from the CIC and doctrine of marks and traces why a substance cannot be constructed from two substances or be divided into two new substances. Let substance x have within its complete individual concept predicates g, h, i… which are true of it past, present and future. Suppose x were to be divided into xα and xβ. One might imagine that both new substances would have all of x's pre-division predicates in common and unique predicates thereafter. But the relevant part of Leibniz's logical notion of substance is that the CIC is sufficiently rich to allow us (or God) to deduce from it all predicates past, present and future. Leibniz's implicit suggestion is that the pre-division predicates would not allow the logical deduction of branching or divided substances. If g, h, i,… imply lα, mα, nα, they cannot also imply lβ, mβ, nβ. A similar argument works against the possibility of the fusion of two substances. Further, if we already grant PII, then it should be clear that the substance having within its CIC predicates g, h, i, … lα, mα, nα, and the substance having within its CIC predicates g, h, i, … lβ, mβ, nβ are numerically distinct substances and not simply one substance in its pre-division phase that has multiplied. Since substances can only naturally arise during God's creation of the world and since substances cannot undergo fusion or fission, it is obvious that the number of substances must remain constant. Finally, if it is the case that it is of the nature of a substance to have a notion so complete that one can deduce from it all its predicates past, present, and future and if substances exist from the creation of the world, then it would seem (relatively) natural to conclude that each substance contains within it a kind of story of the entire universe from its own particular perspective. While more will be said below, what Leibniz is suggesting here is a set of doctrines that he will develop in greater detail: the worlds apart doctrine, the mirroring (or expression) thesis, and the doctrine of universal harmony.