May 16, 2011

In science, the outcome of natural processes is either random or determined by the laws of nature. And scientific inquiry has proven itself to be very powerful in explaining the world and how it came to be the way it is.

Yet, as a Christian, I believe God is active in the world. All the world is the result of God's creative initiative. How can there be causes that are not determined by the laws of nature that science has discovered?

First, it is important to recognize that science has limits, even within its own domain of natural processes. Some processes in nature appear to be chaotic. They are so sensitive to even the smallest error that we can no longer predict their outcome.

Furthermore, at the atomic scale of matter, at the scale of chemical and biochemical processes, we discover an even more fundamental limit. Making measurements and predictions with perfect accuracy becomes entirely impossible.

This imprecision and randomness is built into the foundations of the world, together with the laws of nature. Even if we knew everything that there is to know about nature at any point in time, we could still not predict with perfect precision what happens next.


Science explains the world from the bottom up, beginning with the parts and ending with the whole. The rules that determine bottom-up causality are the laws of physics and related sciences.

Bottom-up causality explains the movement of planets out of the gravity that acts between them and the sun. It explains chemical reactions out of the electromagnetic force between atomic nuclei and electrons.

Bottom-up causality is the stuff of science as we know it. But, as I indicated above, science has its limits. Some things are left undetermined, which gives them the appearance of randomness.

I wonder whether there can be another kind of causality - the whole acting on its parts, or top-down?

I think that the human experience of free will is strong evidence for it. The existence of free will in human beings is experienced as an obvious fact, and it calls for an explanation. Yet, it cannot be explained by the science that we know.

Free will seems to be impossible to explain with the laws that determine bottom-up causality. Those who believe that bottom-up causality is all there is, and this includes a great many scientists, often conclude that free will is no more than an illusion.


However, there is no need for this conclusion. By being limited in its scope and accuracy, bottom-up causality remains open to additional causes other than the laws of physics.

Therefore, the randomness found in nature is actually important. Human freedom in the natural world is possible because there is both randomness and lawfulness in bottom-up causality.

It is necessary to have both. If all were fully determined by laws, there could be no freedom, as nothing could be done differently. If all were left to chance, human freedom could have no consequences, as nothing could have predictable outcomes.

So the results of scientific investigation do not at all question the reasonableness of the Christian faith. Actually, it all fits together quite nicely. In my opinion, understanding human freedom and of the interplay between top-down and bottom-up causality will be the most interesting question to follow for those interested in science and religion.

(This article was originally published on Brother Joachim's online blog where he writes about science and religion: