Enneads V.7: Do Ideas of Individuals Exist?
Leibnitz's Doctrine of the Indiscernibles
(Fourth objection): Granting that the ("seminal) reasons" of the individuals are different, why should there be as many as there are individuals which achieve existence in any one period? It is possible that identical "reasons" might produce individuals differing in external appearance; and we have even granted that this may occur when the ("seminal) reasons" are given entirely. It is asked, is this possible when the same "reasons" are developed? We teach that absolutely similar things might be reproduced in different periods; but, within the same period, there is nothing absolutely identical.
THERE ARE DIFFERENT IDEAS FOR TWINS, BRETHREN, OR WORKS OF ART.
3. (Fifth objection): But how could ("seminal) reasons" be different in the conception of twins, and in the act of generation in the case of animals who procreate multiple offspring? Here it would seem that when the individuals are similar, there could be but one single "reason." Not so; for in that case there would not be so many "reasons" as there are individuals; and, on the contrary, it will have to be granted that there are as many as there are individuals that differ by specific differences, and not by a mere lack of form. Nothing therefore hinders us from admitting that there are different "reasons," even for animal offspring which show no difference, if there were such. An artist who produces similar works cannot produce this resemblance without introducing in it some difference which depends on reasoning; so that every work he produces differs from the others, because he adds some difference to the similarity. In nature, where the difference does not derive from reasoning, but only from differing ("seminal) reasons" the (individual) difference will have to be added to the specific form, even though we may not be able to discern it. The ("seminal) reason" would be different if generation admitted chance as to quantity (the number of offspring begotten). But if the number of things to be born is determinate, the quantity will be limited by the evolution and development of all the "reasons," so that, when the series of all things will be finished, another period may recommence. The quantity suitable to the world, and the number of beings who are to exist therein, are things regulated and contained in the principle which contains all the "reasons" (that is, the universal Soul), from the very beginning.