Spontaneity and the Generation of Rational Beings in Leibniz's Theory of Biological Reproduction

Spontaneity and the Generation of Rational Beings in Leibniz's Theory of Biological Reproduction DANIEL C. FOUKE IN 1712 Leibniz reiterated what had become one of the central principles of his metaphysics after the mid-168os: "It is the nature of a created substance to change continually according to a certain order which spontaneously leads it... through all its states in such a way that one who is omniscient sees all its past and future states in its present state" (GP 4: 518) 9Leibniz attributed no little explanatory power to this doctrine of spontaneity (e.g., GP 4: 48o-87, 52o-~ 4, 554-7x), and it might be expected that in a world in which everything is composed of spontaneously developing beings which "have something vital and a species of perception" (GP 4: 482-83), where biology is in a sense at the root of everything, it would be easier to explain the biological reproduction of humans than in the alternative worlds conceived by Leibniz's philosophical contemporaries. The explanation most consonant with Leibniz's metaphysics would seem to be that it is divinely pre-established that at the moment of biological conception the organism which pre-exists in either the sperm or egg of the parents begins a spontaneous development into a mature human with a rational soul. It might be expected that this development, like all developments in the Leibnizian world, is produced by the individual nature from its previous states, so that what was previously nonrational now becomes rational by its own power. Yet Leibniz is reluctant to adopt such a view, and frequently entertains explanations which seem contrary to the demands of his own metaMythanks to Don Rutherford, Dan Garber, and the editor and referees of the Journal of the HistoryofPhilosophyfor their helpful comments on earlier drafts of this paper. [33] 34 JOURNAL OF THE HISTORY OF PHILOSOPHY ~9:1 JANUARY 1991 physics. This paradox requires explanation, suggesting that there is more to Leibniz's system than standard expositions indicate. l. SPONTANEITY AND THE NATURAL ORDER The doctrine of spontaneity is closely connected to Leibniz's conviction that the natural order must reflect the metaphysical perfection of God. The context in which Leibniz introduces metaphysical perfection implies that the concept is intended to express the perfection of God as manifested in his creative acts. In the Discoursde m~taphysiqueLeibniz applies the concept with particular emphasis on the manner in which God's creative wisdom is to be conceived as a balance between means and ends. This balance is to be interpreted as the production of maximum variety by means of the simplest system of laws consistent with that variety. Leibniz expresses this concept through a number of analogies: the "excellent geometer who knows how to find the best contructions of a problem," the "good architect who manages his resources in order to build in the best fashion," the builder who balances his expenses "with the grandeur and beauty required." "It is true that God has no costs... since God can bring a real world into existence by mere decrees. But when the issue is wisdom, decrees or hypotheses count as expenses in proportion as they are more independent of one another, for reason desires to avoid a multiplicity of hypotheses or principles somewhat as the simplest system is always preferred in astronomy" (DM 4~ [sect. 5]). The notion of metaphysical perfection is primary for Leibniz and provides a criterion by which to judge metaphysical systems. But how to apply the criterion is less than transparent. The requirement of maximum variety consistent with greatest order appears to be absolute: God must create a world in which "all the orders of natural beings form but a single chain, in which the various classes, like so many rings, are so closely linked one to another that it is impossible for the senses or the imagination to determine precisely the point at which one ends and the next begins."' However, maximal variety produced by simple means would not be an adequate manifestation of God's perfect wisdom unless it were realized in the particular form of an intelligible self-contained system. This interpretation of metaphysical perfection motivates Leibniz's criticisms...