Leibniz presents a theory of harmony and perfection in the universe, in
which non-material substantial forms or patterns of predetermined
dispositions make the world what it is. The ultimate source of this
intelligent ordering of the universe is of course God, but God does not
need to intervene in the world because He has already set the perfect
pattern in motion by creating within each thing a substantial form or
soul having a predisposition to behave according to the overall Plan of
Harmony. Leibniz believes that his line of reasoning cannot be avoided,
and he attempts to solve the mind/body problem presented by Descartes.
First, he reasons a metaphysical need for a non-material, spiritual or soul substance, which is the real unity above and guiding material substance. Since matter is infinitely divisible, there can be no real unities in material substances. Since matter is but a collection of parts, only substantial unities could be what is real. The infinite multitude of material divisions can only come from true unities of a higher order than the multitudes derived from them. Leibniz says, "it is impossible to find the principles of a true unity in matter alone or in that which is only passive, since everything in it is only a collection or mass of parts" (3). Only substantial atoms, real indivisible unities, could be the true sources of material action.
These substantial unities are what Leibniz calls `metaphysical points', being non-material and possessing vitality and perception. He explains that "physical points are indivisible only in appear- ance.. only metaphysical or substantial points (constituted by forms and souls) are exact and real" (NSON 11). These substantial points are the first principles of composition and to what any analysis of parts refer. Only the true unities could derive the multitude of physical parts, and unities are needed to organize matter.
Leibniz recalls the `substantial forms' of traditional philosophy. He is looking for the basic metaphysical forms which form the world order. These `forms' for Leibniz are "primitive forces," the basic forces of nature or the original activity of things. And for Leibniz, these forces of nature are not without feeling and appetite. They are what should be called the soul. Thus, the soul is an intelligent and active force determining the course of nature and world events.
There is not just one soul (even though I think we could speak of God as the Great Oversoul), but there are a multitude of souls having a force within the world. These souls are each independent of each other, and yet they are somehow harmoniously related. There is also a hierarchy or grades of souls, some having more of the light of Divinity, which is basically intellect. Leibniz does view that parts of nature other than man do have souls, but their souls are subordinate to, or made for, the souls of minds (i.e., man).
Leibniz reasons that souls must be created perfectly in their beginning and go on forever as they are predetermined, because true unities would not be capable of just being born at any time or from anything, except of course by the power and miracle of God. True unities could never be created from parts, so they must be created from nothing or from God in some beginning of time. There is no final extinction of souls, just as there is no actual beginning. Souls exist and keep existing as they essentially are. He says that "every organized substance has no beginning... its apparent gener- ation is only a development and a kind of augmentation" (NSON 6).
But what do souls do after the death of [their] bodies? It would be unreasonable to assume that they exist useless in a chaos of non-matter. Souls must keep on surviving in the world of form and matter, in order for them to have any meaning. Yet, Leibniz argues against the theory of metempsychosis, the transmigration through time of souls from bodies to other bodies. He instead believes in the transformation or development of bodies and souls according to their inner blueprint.
Souls tend toward perfection within this perfect universe, and yet the perfection they tend toward is the blueprint given to them by God. In other words, God defines the perfection of souls, and all we can know of this perfection is what actually occurs. For Leibniz, souls are perfect in the eyes of God, since God created each rightly, and thus this world is perfect.
Each soul has an original constitution, a predisposition, a pattern of fate or perception. All perceptions of the mind are determined by the particular disposition of that soul created by the perfect God. It is this God-given internal structure or dispositional force within the soul that automatically produces everything - perceptions, actions, and events. Each soul, or "source of action", has within it a God-given blueprint for its own realized perfection, and because God perfectly designed these many internal constitutions or predispositions, all of the souls will act in harmony with all the others. This is essentially a "clockwork" metaphysical model of the universe and the wills within it.
This is Leibniz' answer to the ongoing problem of mind-body correspondence. Descartes clarified the metaphysical position of two independent substances, mind and matter, but he could not adequately solve the problem of their communication and union. One kind of solution, which Descartes held, is that the mind somehow influences the body, and vice versa. Another solution is the "system of occasional causes", which makes recourse to the "general Cause", that is, to God's almighty power and the His universal miracles. Both of these general positions are rejected by Leibniz. Instead, he presents a kind of "clockwork design" argument, which is that God pre-set the internal structure within the soul of minds and bodies to behave in a manner harmonious to each and with all else in the universe.
Thus, mind and bodies do not influence eachother, nor are they [divinely] adjusted to eachother; but they are manufactured perfectly to act in accordance with harmony. There is no communication between mental and physical substances, which Leibniz admits could not occur without divine help, but instead harmonious occurrences of mind and body are set in advance by their internal natures, and thus there is no need for any further divine intervention. Is this not merely a theory of predetermination?
Leibniz rejects the theory of mechanical actions and cause-effect influences between minds and bodies, even though he maintains a notion of predeterminism. We are free in that we are independent of influences from other souls, since each soul is only governed by its internal nature. For souls destined to following higher laws, "no changes of matter can make them lose the moral qualities of their personality" (NSON 8). Each immortal soul is "regulated by its own nature, protected from all external accidents... sufficient unto itself, containing the infinite, expressing the universe" (NSON 16).
Thus, each independent soul is essentially connected to the overall harmony of the universe, and all of the souls, in effect, harmonize with eachother and the universe as a whole. Leibniz states, "we must say Each soul is in harmony with the rest of the universe, because each soul is "representative of the universe", so "the series of representation produced in the soul will correspond naturally to the series of changes in the universe itself" (NSON 15).
And thus, we have Leibniz' hypothesis of harmony. It appears to me to be a theory of predeterminism based upon the analogy that machines act in a set manner determined by their internal constitution or design. Leibniz believes in a predisposition of the soul. Each soul then acts only according to their disposition, which would appear to lead to a world of many souls acting independently of eachother, without any perceptual window to eachother or any will to conform or adjust to external forces. Yet, Leibniz' solution to this consequential anarchy is that God, the Creator, has from the beginning predetermined the internal nature of each soul in such a way that each soul will act in harmony with all others, that "God has from the first created the soul or any other real unity in such a way that everything arises in it from its own internal nature through a perfect spontaneity relatively to itself, and yet with a perfect conformity to external things" (NSON 14).