Where the Conflict Really Lies: Science, Religion, and Naturalism (12 page)

But the right hand conjunct of (6) is obviously false: clearly there is a possible world that (i) shares its past with the actual world, (ii) is not causally closed (because, perhaps, God acts specially in it) and (iii) does not share its future with the actual world. Therefore determinism, which entails (6), is false. Indeed, given the usual view that propositions of the form
necessarily p
are noncontingent, either necessarily true or necessarily false, (6) is necessarily false; hence determinism, which entails it, is also necessarily false.

Mackie’s suggestion seems a good description of the laws of nature, and certainly fits nicely with the Newtonian picture.
²³
So thought of, the natural laws offer no threat to special divine action. Miracles are often thought to be problematic, in that God, if he were to perform a miracle, would be involved in “breaking,” going contrary to, abrogating, suspending, a natural law. But given this conception of law, if God were to perform a miracle, it wouldn’t at all involve contravening a natural law. That is because, obviously, any occasion on which God performs a miracle is an occasion when the universe is not causally closed; and the laws say nothing about what happens
when the universe is not causally closed. Indeed, on this conception it isn’t even possible that God break a law of nature.
²⁴
For to break a law, he would have to act specially in the world; yet any time at which he acted specially in the world would be a time at which the universe is not causally closed; hence no law applies to the circumstance in question and hence no law gets broken.

Objection: why can’t we just as well say that the law is P itself, rather than what (LN) says it is? Why can’t we say that Newton’s law is just the result of deleting that proviso “when the universe is causally closed” from the above formulation of it? And then wouldn’t divine action have to involve breaking a law, in which case there really is conflict between classical science and special divine action?

Reply: we can certainly think of laws like that if we wish; it’s a free country. If we do, however, then classical science as such doesn’t imply that the laws as ordinarily thought of—Newton’s law, for example—are actually
true
; it doesn’t imply that they are exceptionless generalizations. What classical science does imply is that these laws hold when the material universe is causally closed; but again, it is no part of classical science to assert that the material universe
is
causally closed. So taking laws this way, special divine action would indeed be “breaking” a law, but it would be no part of classical science to assert that the laws are not broken. Once again there would be no conflict between science and divine special action, including miracles.

What we’ve seen so far is that classical science doesn’t entail either determinism or that the universe is in fact causally closed. It is therefore entirely consistent with special divine action in the world, including miracles. Hands-off theologians can’t properly point to
science—not even to eighteenth- and nineteenth-century classical science—as a reason for their opposition to divine intervention. What actually guides their thought is not classical science as such, but classical science plus a gratuitous metaphysical or theological addition—one that has no scientific credentials and goes contrary to classical Christianity.

The Newtonian picture isn’t sufficient for hands-off theology; so what is it that guides the thought of these hands-off theologians? The Laplacean picture. Here the classic statement, naturally enough, is by Pierre Laplace:

We ought then to regard the present state of the universe as the effect of its previous state and as the cause of the one which is to follow. Given for one instant a mind which could comprehend all the forces by which nature is animated and the respective situation of the beings that compose it—a mind sufficiently vast to subject these data to analysis—it would embrace in the same formula the movements of the greatest bodies of the universe and those of the lightest atom; for it, nothing would be uncertain and the future, as the past, would be present to its eyes.
²⁵

Note that this great mind would have to have quite remarkable powers of computation: the classical three-body problem—the problem of giving an analytical solution for the equations of motion for three bodies—has not so far been solved, let alone the classical n-body problem for large n. Note also that this demon (as she has
come to be called) would have to know the initial conditions with enormous—indeed, perfect—accuracy:

In a game of billiards suppose that, after the first shot, the balls are sent in a continuous series of collisions, that there are a very large number of balls, and the collisions occur with a negligible loss of energy. If the average distance between the balls is ten times their radius, then it can be shown that an error of one in the 1000th decimal place in the angle of the first impact means that all predictability is lost after 1000 collisions.
²⁶

What, exactly, must be added to the Newtonian picture to get the Laplacean picture? Determinism plus
the causal closure of the physical universe
.
²⁷
Although this addition is not at all implied by the physics (as I said, it’s a philosophical or theological assumption), it was and is widely accepted, and indeed so widely accepted that it is often completely overlooked in contexts where it is crucial.
²⁸
That the universe is indeed closed, once more, is not testified to by classical science nor a consequence of it. In touting the prowess of his calculating demon, Laplace was just
assuming
that God couldn’t or wouldn’t act specially.
(He was also assuming that the laws of physics are
deterministic
or non-probabilistic and
complete
, in the sense that they apply at every time to every configuration of particles.) He wasn’t getting this idea out of the physics, even though it has been widely accepted and often thought to be somehow enforced by classical science. And it is this Laplacean picture that guides the thought of the hands-off theologians. If it is true, as Gilkey suggests, that these theologians, like Martin Luther, can do no other, then it is the Laplacean picture that has them so firmly in its grip.

It is also the Laplacean picture—the laws of classical science plus the causal closure of the physical universe—that leaves no room for divine action in the world. Recall that the laws are of the form

(LN) When the universe is causally closed (when God is not acting specially in the world), P.

The Laplacean demon assumes that the universe is causally closed. But then she assumes that the antecedents of the laws are satisfied, and therefore she assumes, for each of the natural laws, that its consequent is true. Given the consequents of the laws and the state of the universe at any one time (and given that the laws of nature are complete and deterministic), the state of the universe at any other time is a necessary consequence. Hence, given the laws God originally sets for the universe together with causal closure and the state of the universe at any one time, she can simply deduce the state of the universe at any other time.

And this would leave no room for special divine action. If God ever acted specially, that Laplacean demon would be unable to make those calculations. If God acted specially, there would be a time
t
such that the state of the universe at
t
doesn’t follow from the consequents of the laws together with the state of the universe at any other
time. Therefore, if the demon tried to calculate what happens at
t
by using the laws and what happens at some other time
t*
, she would get the wrong answer. (Of course it also follows directly from causal closure alone that God doesn’t act specially in the world.) This picture (think of it as a proposition) does not entail that God
cannot
act specially in the world. Even if the physical universe is causally closed, it isn’t a necessary truth that it is, and presumably God, being omnipotent, could act specially in it if he saw fit. What the picture entails is only that as a matter of fact he
does not
act specially.

This picture also has an important implication for human freedom. For if the universe is causally closed, the consequents of the laws together with S(
t
) (where
t
is, let’s say, a million years ago and S(
t
) is the state of the universe at
t
) entail the current state of the universe, S
_{(just now)}
. So suppose S
_{(just now)}
includes my going to the kitchen for a drink. If so, and if the Laplacean picture is correct, it was not within my power to refrain from getting a drink then. For it would have been within my power to refrain from going to the kitchen then only if it had been within my power, then, to perform some action
A
(where refraining counts as an action) such that if I had performed
A
, then either the consequents of the natural laws would have been different from what in fact they are, or S(
t
) would have been different from what
it
was, or the physical universe would not have been causally closed. It would have been within my power to avoid that action only if either the laws, or the state of the universe a million years ago, or the causal closure of the universe were within my power—only if I could have done something such that if I
had
done that thing, then either the physical universe would not have been causally closed, or else either the laws or that state of the universe would have been different from what in fact they are. It seems likely that none of these things is within my power. Therefore it is plausible to think that my action of going to the kitchen for a drink was not a
free action.
²⁹
Hence the Laplacean picture implies (or strongly suggests) that no human actions are free.
³⁰

Whether determinism is incompatible with human freedom depends on the nature of the laws. If the laws are no more than Humean descriptive generalizations, if they merely record what actually happens, then there is no reason to think that determinism
is
incompatible with human freedom. For consider some law
L
that bears on what I do: perhaps
L
together with other things entails that I will raise my hand at
t
. If
L
is no more than a complex descriptive generalization, then it describes a situation that includes, among other things, my raising my hand at
t
. But so far this is entirely compatible with my having the power to refrain from raising my hand at
t
; the mere fact that I
do
raise my hand then doesn’t imply that I wasn’t able to refrain from raising it then. (Of course if I had refrained from raising my hand,
L
would have been false and hence would not have been a law.) The same goes for a conception of laws like that of David Lewis: a set of exceptionless generalizations that is maximal with respect to a combination of strength and simplicity. Here (as in the previous case) laws would supervene on particular matters of fact. And on this conception of law, as in the previous case, it is entirely possible that I have the power to refrain from performing an action
A
such that the laws together with the state of the universe
at some time
t
entail that I perform
A
. Again, if I were to do so, then some proposition
L
that is in fact a law, would not have enjoyed lawhood, because it would not have been an exceptionless generalization. (Laplace, of course, was thinking of those laws as the laws of classical science; and presumably it is not within the power of any human being so to act that a proposition that is in fact a law of physics would not have been a law of physics.)

Although the Laplacean picture implies that human beings are not free; it’s worth noting that the same definitely does not go for the Newtonian picture. Just as the Newtonian picture leaves room for divine action in the world, so it also leaves room for human free action. What is crucial here is that the Newtonian picture does not imply that the material universe is causally closed; but then, just as it is compatible with the Newtonian picture that
God
act specially in the world, so it is compatible with that picture
that human beings
act freely in the world. For suppose—along with Plato, Augustine, and Descartes and many contemporaries—that human beings resemble God in being immaterial selves or substances.
³¹
Then just as God, who is an immaterial being, can act in the hard, heavy, massy physical universe, so too, perhaps, can human beings; God could confer on them the power to cause changes in the physical universe. Perhaps my willing to move my arm causes neurophysiological events in my brain, which in turn cause my arm to move. Classical physics and the Newtonian picture, therefore, unlike the Laplacean picture, do not imply either that human beings cannot act freely or that God does not act specially in the world.

Laplace’s picture is accurate only if the universe is closed: only if God doesn’t act specially in the world. We could think of the Laplacean
picture as the Newtonian picture plus closure. This Laplacean picture, clearly enough, is the one guiding the thought of Bultmann, Macquarrie, Gilkey, et al. There is interesting irony, here, in the fact that these theologians, in the name of being scientific and up to date (and who wants to be thought unscientific, or obsolete?), urge on us an understanding of classical science that goes well beyond what classical science actually propounds (and, as we’ll see in the next chapter, they also urge on us a picture of the world that is scientifically out of date by many decades).

As we have seen, however, classical science doesn’t assert or include Laplacean determinism. The laws don’t tell us how things always go; they tell us how they go when the relevant system is causally closed, subject to no outside causal influence. In classical science, therefore, there is no objection to special divine action (or for that matter to human free action, dualistically conceived). As we have also seen, to get such an objection, we must add that the universe is causally closed, which is not itself part of classical science. Accordingly, classical science is perfectly consistent with special divine action, including miracles. So far, therefore, we haven’t found a religion/science conflict; what we have is only a conflict between religion—Christian belief, for example—and a particular metaphysics according to which the universe is causally closed.