By Jim J. McCrea
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Within the rational order of reality, things or events have their own proper ability to cause other things or events. The universe has innumerable causal chains, in which within a given chain one thing causes another which causes another and so on. This understanding of causality makes human reason and science possible. It may be argued by materialists that if this is so, it would leave no room for the action of God in the universe since everything in the universe acts according to natural causality. However, if we look at the nature of *chance,* this is not so.
Consider three causal chains: A, B, and C; in which A1 causes A2 which causes A3 etc.; in which B1 causes B2 which causes B3 etc.; and in which C1 causes C2 which causes C3 etc.
However, the causal chains may *intersect.* The intersection of causal chains happens all the time in the universe. Although each term in a causal series is caused by the one preceding, the intersection of different causal chains themselves do not come under natural causality. It is not a natural cause that determines their meeting. It is a purely fortuitous event. As this does not come under natural causality, it leaves an opening for the First Cause of All, God, to determine their meeting. As a result it is possible for God to be continually intervening in the natural world while leaving natural causality intact and not continually resorting to miracles.
The 20th century Catholic philosopher, Jacques Maritain, gives an example here of the intersection of three causal chains and the fact that their intersection is not the result of a cause in this universe and which has no ontological unity.
Maritain says:
"Chance, a fortuitous event, presupposes the mutual interference of independent lines of causation. Chance, and this is the basis of the ancients' notion of it, is the result of an irreducible pluralism, the plurality of the causal series which meet at a given moment. It is not the fact that it cannot be foreseen that constitutes chance. A fortuitous event can be foreseen, if its constituent factors are sufficiently simple. But it is a fortuitous event notwithstanding, since it is a mere encounter.
You may remember Aristotle's example. Is it true to say that a man is killed by brigands because he has eaten too salt viands? What is the link here between cause and effect? He has eaten too salt viands, becomes thirsty, and goes out to a spring. Behind the spring brigands are in hiding who profit by the opportunity to murder him. There is a chain of causes and effects. Is the entire chain necessary? To understand the conception of chance which is far more difficult than is often supposed, we shall examine this instance of it. There are here three series of causes. One extends from the salt food to the thirst. It is normal and in the natural order of things that salt food should cause thirst, the thirst excite the desire
to drink, and the desire lead to the action. In another series there is a preliminary condition that there should be no water in the house. Moreover, there must be a spring near. And its existence in the vicinity must itself have a cause, namely the presence in a particular locality of underground water which in turn depends upon an entire series of geological facts. There is a third series of causes which accounts for the presence of the brigands at that particular place. Their presence there depends, for example, on their having hidden in the woods from the pursuit of the police, and this is itself the result of previous crimes they have committed. Thus three independent causal chains meet, and the man's death is the result of their meeting. Each of the causes here operative continues or would have continued to act in its own line. The brigands would have continued their career of robbery, the spring its causal action, erosion of the earth's surface, evaporation, and had the victim not met his death, the drink he had taken would have produced a particular physiological effect upon his organism.
Every event in each series of causes has therefore its cause within the series. But the encounter between an event of one series, for example, the presence of the brigands and events of the other two, the existence of the spring and the desire to drink has not as such any cause in the entire universe. That is to say there is no nature, no natural agent predetermined by its structure to this encounter of the three events, nor any created intelligence that designed it.
The illustrative diagram makes clear the irreducible multiplicity in which chance consists. Each of three causal lines diverges from the rest as we trace the series backwards, so that the farther back we go in each series, the more remote are we from the possibility of finding a cause pre-determined to the meeting of the three series and accounting for it.
That is to say the encounter of the three causal lines at a given moment is indeed a contingent fact but not a contingent being. This is the difficult and important point to grasp in the theory of chance. The encounter has no being, save in thought. Certainly it exists. But it is not an essence. It is a pure coincidence, and possesses no ontological unity requiring to render its existence intelligible an active structure preordained to it. It is neither a genuine being, nor a genuine unity and therefore does not possess a genuine cause, in the ontological sense which I have explained."
From "A Preface to Metaphysics: Seventh Lecture"
Jacques Maritain was one of the foremost Catholic philosophers of the 20th century.
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Addendum:
One asks: cannot chance be predicted mathematically, and what is the significance of that?
To understand the theory of chance, we must distinguish what is necessary from what is accidental.
The fact that a second billiard ball picks up the momentum that a first loses upon collision with it, is essential. However, the numbers that the billiard balls have (e.g. speed, direction, and position) are accidental (non necessary). It is these numbers that determine whether the balls collide or not.
With this in mind, all real beings have what is known as *Poincare resonances.* A Poincare resonance is a point in a thing where its equations divide be zero. As a result, the behavior of it is undetermined. It is set "free" at that point. God as prime mover then can decide what its trajectory it, and adjust its numbers while respecting the physical laws of the thing (while not resorting to miracle). With such adjustments on things, God can decide whether causal line intersect or not.