The problem of understanding God as he is pictured by both Christian Theologians and Christian philosophers while at the same time maintaining a completely rational universe has to do with free will and value. Augustine's concept of grace appears to solve the problem, but it does not, it merely ignores it. First, if an omniscient God knows in advance the outcome of all events and of every decision, does that make free will a chimera? More importantly, does that make science an exercise of futility. Is man merely a race of automatons going through the paces set up by his master? Second, can there be such a thing as good and evil. I don't mean in the sense that Augustine refuted, by saying that evil is not a positive thing but a privation. I mean as a value placed on some act. If God made the world, is it good only because he made it? Could a perfect God make a world that would not be determined good? These are the questions that . Leibniz attempted to solve while still maintaining a completely rational universe.

Therefore I am far removed from the opinion of those who maintain that there are no principles of goodness or perfection in the nature of things, or in the ideas which God has about them, and who say that the works of God are good only through the formal reason that God has made them. If this position were true, God, knowing that he is the author of all things would not have to regard them afterwards and find them good, as the Holy Scripture witnesses.

What is implied by this statement is that God must have made a choice concerning the universe he created and the criterion for that choice must have been something objective, some varying feature of the variety out of which he was going to choose. This is particularly true since whatever he chose had to be the best possible or else it would imply an imperfection in God. Thus we arrive at the first of a set of principles through which we can understand a created rational universe, the principle of divine perfection. This is the principle whereby we can understand the criteria by which God chooses from among the available variety that which is best. That criteria . Leibniz said, is the simpleness of means and the richness of effects.

When the simplicity of God's way is spoken of, reference is specially made to the means which he employs, and on the other hand when the variety, richness and abundance are referred to, the ends or effects are had in mind. Thus one ought to be proportioned to the other, just as the cost of a building should balance the beauty and grandeur which is expected.

Leibniz was a contemporary of Isaac Newton. In fact both are credited independently of inventing the infinitesimal calculus. Thus it was necessary that his description of the world be consistent with Newtonian science. And it is important too, that it be consistent with the assumptions and implications put forward by Spinoza. Remember he was not trying to refute Spinoza, he was attempting to improve on him by providing a description of reality which was consistent with Spinoza but that also allowed for free choice for both God and man. Since he saw that concept of cause, as in Spinoza's works, tied God to necessary actions, to actions that were fixed by their causes and thus making choice impossible, he replaced it with the conception of "sufficient reason." God's choices are not the result of cause, they are the result of sufficient reason. Thus, when God chooses from the multiplicity of possible worlds, he is not caused by necessary laws as Spinoza had put it. But this opens a new question. How can one, considering the evil men experience in this world, accept such a view? Why does God in his infinite power allow the beauty of the world to be marred by evil actions? He answered this question simply enough but posed the problem of why, of what determines what should be allowed and what should be commanded. . Why, in other words, does God allow specific actions not all good to occur?

...for if the action is good in itself, we may say that God wishes it and at times commands it, even though it does not take place; but if it is bad in itself and becomes good only by accident through the course of events and especially after chastisement and satisfaction have corrected its malignity and rewarded the ill with interest in such a way that more perfection results in the whole train of circumstances that would have come if that ill had not occurred,if all this takes place we must say that God permits the evil, and not that he desired it, although he has cooperated by means of the laws of nature which he has established. He knows how to produce the greatest good from them.

In order to make sense of what Leibniz has in mind we need to understand his idea of a complete individual conception. First, he used the term substance in much the same way as Aristotle did, meaning specific entities that we could talk about. Yet he also intended to meet all of the requirements that Spinoza had for his conception of substance and at the same time to expand it to show that both God and man have true free will. So he used the concept of substance in both Aristotelian and Spinozistic senses. Treating the concept in Aristotelian terms, he returned to the Islamic idea of the existence of possible substances.

Every true predicate of a substance, he said, that is everything that can be said about a substance that is true, is true in the nature of the substance. If you reflect back you will see that this is implied by the Spinozistic philosophy if you apply it to his concept of everything that exists as modes of Gods existence. What this leads to is the idea that if you knew everything that could ever at any time be said about something then you would know immediately everything that was ever going to happen to it. In this way he could speak of an infinite number of substances rather than the single substance of Spinoza. . Leibniz called this the complete individual conception of the substance.

This being so, we are able to say that this is the nature of an individual substance or of a complete being, namely, to afford a conception so complete that the concept shall be sufficient for the understanding of it and for the deduction of all predicates of which the substance is or may become subject.

To put this in simple terms since whatever can be said of an individual substance at any time during its existence is necessarily true therefore cannot not be true thus a complete individual conception of that substance includes everything that can ever be predicated to it. Our concept of Alexander the Great as a King does not afford a complete individual conception of him. However God, seeing the complete individual conception of Alexander sees that it includes absolutely everything about him, that he will conquer Darius, even knowing whether he actually died of natural causes or was poisoned. God would know this because he would know the complete individual conception of Alexander and thus everything that would ever happen to him.

This would seem to lead to a fatalism even more inevitable than Spinoza's. However, Leibniz proposed that there are an infinite number of possible substances each with its own complete individual conception. Not all of these possible substances could exist in the same world, however, since the conceptions of some are inconsistent with the conception of some others. This leads to the Leibnizian concept of compossible worlds. Substances that can exist together in the same world he called "compossible" substances. Though there are infinite possible substances, the number of substances that are compossible, that is, that can exist in the same world together is finite. And, there are a large, though finite, number of such compossible worlds each with its own set of compossible substances. It is from this variety of possible worlds that God chose to create the world which he did indeed create. All of the other worlds exist only as possible creations in the infinite mind of God. This world was chosen for existence actively by God only after examining all other possible worlds and it was chosen for rational reasons. This world resulted in the greatest variety with the simplest of means. God did choose well because God sees nothing that is not the very best that is possible. But he did so for rational reasons.

Spinoza said that no substance could be limited by another substance. This was a necessary assumption for a rationally developed universe because if it were not so then one substance would be at least partially developed by its interactions with other substances and not entirely by God. A similar problem became apparent for Leibniz since if God were to choose from among many possible worlds entirely on the basis of individual substances as complete individual conceptions then these substances must exist independently of each other. In other words, the complete individual conception of a substance is a permanent characteristic of a substance and not something developed out of its interactions with other substances and their environment. Thus he taught that all substances are composed of monads.

Monads are infinitely small and infinitely hard. Everything that is consists of assemblies of these. He called monads windowless meaning that they are in no possible way aware of other monads. However, each monad internally comprises the entire universe as seen from its particular point of view. Thus neither monads nor the substances that are built out of them interact with each other. Everything that happens to them, all of the actions that they initiate, are part of their complete individual conception. There is an appearance that substances interact, for example we imagine people interacting, talking, arguing, but it is only an appearance, because each monad experiences its vision of the operations of the universe in solitary. However, since God created all substances and since all substances are aware of the universe from their particular point of view and because God has caused all of the substances to experience things together in perfect unison, it appears as though they are interacting. This is only because the world as created by God operates on the basis of pre-established harmony. As though every monad had its own internal clock and all monads clocks kept perfect time with each other. Some of the confusion in Leibniz description of the world can be eliminated by considering that when he talks about substances as compossible entities he is using the concept of substance in an Aristotelian sense. When he turned his attentio to monads, he was using the concept of substance in a Spinozistic sense. Spinoza's substance could only be one because otherwise it would be limited by others and thus partially determined by them. Leibniz' monads could not be liomited by any others because each was simply a description of the entire universe from the particular point of view of one infinitely small particle which was aware of the universe from its own point of view but totally unaware of any other monad. Thus each monad was equivilant to the single substance of Spinoza.

There were others who could follow Leibniz up to the point but who would then balk because they felt that it sounded like God created the universe, set its clock and then became disinterested. They took the stand that the perfect timing of all of the monads was accomplished through an active God. That God actively maintained the unison of all creatures. These were called occasionalists.

These rationalist views of the universe and God seem a little fantastic to us who live in the twentieth century. In a sense they represent the beginning of a new cultural world. Newton's Principia was written after Leibniz' metaphysics came into popularity in the next century. With this one book Isaac Newton changed the scientific and cultural view of man and his universe to where a reversion to the past would no longer be possible. Taken as a whole the rationalist philosophies seem to be anachronisms of a chaotic period in the development of western thought. But buried in them lie hidden the forces that would drive the west into its future. From this point on philosophers might take issue with, or might collaborate with, but none could ignore Descartes, Spinoza and Leibniz.