Divine Action in the World, Part 3

| By Alvin Plantinga

In part 2 or this series, philosopher Alvin Plantinga began examining classical science based on Newtonian physics. Here in part 3, he continues his discussion that classical science alone is not sufficient to “prohibit” God from acting in the world. One must also add the philosophical concept of determinism or a closed-universe to get a truly hands-off theology. But those concepts are not strictly a part of science itself, but rather unnecessary add-ons that we are not obliged to accept.

In this four-part series, we provide the video of Professor Plantiga’s lecture as well as a written version of his presentation.


So then, to get hands-off theology or anti-interventionist theology, we need more than just classical science as such. Classical science as such does not give that to us. It does not preclude God acting specially in the world. These theologians and philosophers say that, but the fact of the matter is that it’s not true; to get hands-off theology, we need more than classical science.

We need to add that the physical universe is closed. That’s what we have to add, or alternatively, we have to add determinism, which will come to the same thing here where the natural, the common definition of determinism is this: the natural laws plus the state of the universe at any one time entails, determines, the state of the universe at any other time.

You get the idea? So, you have got the state of the universe, the whole universe, at one time—a complete description of it; a description that says where each particle is and what its velocity is and what its direction is and what its mass is and so on (all these parameters); you have got a complete description. That, together with the laws of nature, will entail the state of the universe at any other time, will imply the state of the universe at any other time so that if you were sufficiently smart, (I doubt anybody here is that smart) and you knew exactly what the universe was at that time ‘t’, you could just deduce what it is at any other time, in the past as well as in the future.

Here is a paradigmatic statement for this way of thinking, this deterministic way of thinking. Pierre Laplace said,

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 even 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—given a mind like that, 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 well as the past would be present to its eyes.


Napoleon is alleged to have asked Laplace, “But what about God in your system?” and he is reputed to have responded, “I have no need of that hypothesis”. But that’s the thought—his thought is the universe is such a sort that if you have a detailed knowledge of any one bit of it at any one time, that if you knew the state of the universe at any one time, and you knew all the physical laws, and you were really smart, you could just deduce what it would be at any other time.

Right, and that’s what we could think of as determinism, and of course, if determinism were true, then God would not act specially in the world. If determinism were true, it would follow that God never acts specially in the world, because if he did act specially in the world at some time, then that great mind that Laplace talks about would not be able to conclude that God is doing that from knowing what the universe was like at some other time.

I think the thing to say here is that this Laplacian picture including determinism is accurate only if the universe is causally closed, only if the material universe is causally closed. Only if God does not act specially in the world, because if God did, then that great Laplacian mind would not be able to make these calculations. So we could think of the Laplacian picture as the Newtonian picture plus closure, plus the idea that the physical universe is causally closed, and this is the picture that’s guiding the thought of Bultmann, Macquarie, and Gilkey—these theologians.


I think there are two interesting ironies in their saying this. The first irony is that as a matter of fact, classical science doesn’t have this implication at all. It doesn’t imply that God doesn’t or couldn’t act specially in the world. It doesn’t imply that at all because the classical scientific laws together with the conservation laws are statements about what closed systems are like, and any system in which God did something (created a full grown horse let us say) would not be a closed system, and thus would not be one of the systems the law is talking about.

The other irony is that in the name of being scientific enough, these theologians were urging on us a picture of the world that was scientifically out-of-date (by a long time) when they were urging it. Classical science had already been superseded by quantum mechanics and relativity theory—both general relativity and special relativity. So they were urging on us, saying “Well God can’t act specially in the world.” They were urging this on us first by misunderstanding classical science and then secondly, by failing to realize that classical science is not the eminent kind of science anymore. So, I am inclined to think they should be ashamed of themselves.

So, we can think of the laws as describing how things go when the universe is causally closed, when it is subject to no outside influence. Here is a statement from J.L. Mackey. J.L. Mackey is himself no friend of theism, not a Christian or a believer in God at all, but what he says here seems to me to be correct:

What we want to do here is to contrast the order of nature with a possible divine or supernatural intervention. The laws of nature, we must say, describe the way in which the world, including of course human beings, works when left to itself, when not interfered with. A miracle occurs when the world is not left to itself, when something distinct from the natural order as a whole intrudes into it.

If you ask yourself now what then would the form of the natural laws, what kind of form would they take, if Mackey or something like Mackey were right, then it would go like this: NL—for natural laws—when the universe is causally closed, that is when God is not acting specially in the world, then P, where P would be the way we ordinarily think of the law.

It would go like this: When the universe is causally closed: then for any two particles or any two physical objects they attract each other with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them, and the same for the other laws; they would all have a preface "when the universe is causally closed". That seems a quite good description of the laws of nature, and it fits well with the Newtonian picture, and so far the natural laws offer no threat to divine special action, including miracles.

So, I say there is in classical science as such no objection to special divine action or to human free action. In the same way as this deterministic or Laplacian picture precludes divine action, it also precludes human free action in the world (we could talk about that in the discussion period if you like, but I don’t want to talk about it now because I don’t have that much time). Classical science, just as such, does not make any objection to special divine action or to human free action. To get such an objection, we must add that the universe is causally closed—that is a metaphysical or theological add-on, not part of classical science. Classical science as such is perfectly consistent with special divine action including miracles, walking on water, rising from the dead, creating ex-nihilo a full-grown horse, and so on. There is no science-religion conflict here at all; there is only a religion-metaphysics conflict.

From a presentation sponsored by Biola University’s Center for Christian Thought, and delivered February 12, 2012 at EV Free Church, Fullerton, CA. Used by permission.


About the Author

Alvin Plantinga

Alvin Plantinga is the inaugural William Harry Jellema Professor of Christian Philosophy at Calvin College, as well as emeritus John A. O'Brien Professor of Philosophy at the University of Notre Dame. He received his B.A. from Calvin College and his PhD from Yale. He taught at Calvin College for 19 years prior to his 28 years at Notre Dame. Acclaimed for his work on metaphysics, the problem of evil, and the epistemology of religious belief, he has written books such asGod and Other Minds (1967), Does God Have a Nature? (1980), Warranted Christian Belief (2000), and most recently,Where the Conflict Really Lies: Science, Religion, and Naturalism. (2011). Dr. Plantinga is best known for his Christian epistemology that justifies belief in God without external evidence, his “free will defense” to the logical problem of evil and his evolutionary argument against naturalism.