We proceed to the fourth article thus:
1. It seems that divine providence does impose a necessity on what it provides. An effect happens by necessity if it follows inevitably from a cause which exists or pre-exists through itself. The philosopher proves this in 6 Metaph., text 7. Now divine providence pre-exists, since it is eternal. Its effects also follow inevitably, since it cannot be frustrated. Divine providence therefore imposes a necessity on what it provides.
2. Again, every provider makes as certain as possible that his work shall not fail. Now God is all powerful. He therefore ensures what he provides by means of the certainty of necessity.
3. Again, Boethius says (4 De Consol.6): "the destiny which is unalterably decreed by providence confines the actions and fortunes of men by the indissoluble connections of causes." This implies that providence imposes a necessity on what it provides.
On the other hand: Dionysius says (4 Div. Nom., lect.23): "the corruption of nature is not due to divine providence." Some things, indeed, are contingent by nature. Divine providence does not therefore impose necessity on things to the exclusion of contingency.
I answer: divine providence imposes necessity on some things, but not, as some have believed, on all things. Providence ordains things for an end, and except for the divine goodness which is an end separated from them, the principal good in things themselves is the perfection of the universe. Now the universe would not be perfect if things did not exhibit every grade of being. Divine providence therefore produces every grade of being. It has accordingly prepared necessary causes for some effects, so that they may occur through necessity, and contingent causes for other effects, that they may occur contingently, each according to the condition of its proximate cause.
On the first point: the effect of divine providence is not merely that a thing should happen in some way. Its effect is either that it should happen contingently, or that it should happen through necessity. Whatever divine providence decrees shall happen inevitably and through necessity, happens inevitably and through necessity. Whatever it intends to happen contingently, happens contingently.
On the second point: the order of divine providence is immovable and certain in this, that everything that God provides happens in the manner in which God provides it, whether through necessity or contingently.
On the third point: the indissolubility and unalterability of which Boethius speaks refer to the certainty of providence itself, which fails neither to provide its effect nor to provide it in the manner which it decrees. They do not characterize the effects as occurring through necessity. We must bear in mind that necessity and contingency properly depend on the manner in which a thing exists. Its mode of contingency or necessity, therefore, really depends on the manner in which God provides it, since God is the universal provider of all that exists. It does not depend on the manner in which any particular provider provides it.