Chance, quantum physics and methodological naturalism

Worst of all, the whole scheme [of methodological naturalism –DHC] works only with deterministic “laws.” Consider the decay of a radioactive nucleus, which cannot be predicted by scientific laws as we know them. The individual event of decay, in contrast to statistical prediction for many instances of decay, lies outside the domain of “law,” and so there is no way of saying whether it is “natural” or “preternatural” or “supernatural.” Biblical teaching indicates that God does it. And scientists cannot find a deterministic secondary cause, so they have no “natural” explanation at all. An event that has no secondary cause but only a primary cause, namely God, is usually considered “supernatural.” And yet myriads of such quantum mechanical events are happening every second. In terms of frequency, they are “normal” and “natural.” Conceptually, the distinction between natural and supernatural threatens to breaks down. This breakdown implies that the recipe for “methodological naturalism” has difficulties.

But methodological purists may attempt a rescue operation: Chance with a capital C fills the gap in naturalism. Chance is treated as a part of “nature.” That is one way of choosing to talk. … it also raises the question of whether methodological naturalism, in some forms, involves intrinsically the appeal to Chance as a substitute god. Such a move presupposes the absence of God, rather than presenting a coherent argument. (Vern S. Poythress, Chance and the Sovereignty of God, 130-1)

Quantum physics is a mysterious field of physics dealing with subatomic particles, even those smaller than electrons. The strange nature of quantum mechanics is such that weird phenomena such as tunneling and entanglement exists for these small particles. There is a real sense of indeterminacy in this field, expressed most clearly in the Heisenberg Uncertainty Principle, where the uncertainty regarding momentum is inversely proportional to the uncertainty concerning position, of any one particle. Accordingly, the issue of chance and indeterminacy will come up in that particular field.

Vern Poythress, in attempting to reject methodological naturalism, uses a particular application of quantum principles in nuclear physics, concerning the radioactive decay of an atom, to disprove methodological naturalism. He argues that the indeterminacy of the decay of one radioactive nucleus results in there being no "deterministic secondary cause," and thus there is no real natural explanation at all for the decay of one radioactive nucleus. Thus, methodological naturalism is falsified, unless chance is taken to be a god.

Now, while I fully believe in the full sovereignty of God, Poythress' argument is not helpful here. The 'indeterminacy' of whether a radioactive nucleus decays can be taken to mean there is no secondary cause deciding whether any one particular radioactive nucleus decays or not, or rather the secondary cause does not operate in a deterministic manner. Take as an analogy the Boltzmann distribution of gas particles, which shows the statistical distribution of the energies of all gas particles. Any one particle will have a definite energy, but one does not know the particular energy of a particle when one measures the energy of the gas particles as a group (which translates to the temperature of the gas). Likewise, we perceive the distribution of radioactive decay of radioactive nuclei as an exponential decay curve, but do not know when any one particular radioactive nucleus will or will not decay. What is important here is that just because there is no determining secondary cause does not imply that there is no secondary cause at all.

This solution is not to make chance a "god," but merely to state the indeterminacy inherent in our knowledge of such small particles. Just like looking at gas molecules in a Boltzmann distribution, so likewise we look at nuclei of radioisotopes. Even if we could remove the high energy gas molecules, this does not change the distribution of the energies of the gas molecules from a Boltzmann distribution but rather a new Boltzmann distribution curve would form. So likewise, the thought experiment of putting two nuclei that would decay within the first half-life together would not result in two nuclei decaying within the first half-life, but that one will decay and the other would not.

The indeterminacy of an individual particle is situated in the determinacy of statistics. Therefore, Poythress' argument against methodological naturalism fails. Statistics is not a god of 'chance,' but an actual mathematical and scientific field. It no more indicates a lack of secondary causes than the use of statistics in dice rolling indicate the absence of secondary causes.