Does QM have anything to do with God? Physicist Stephen Barr apparently thinks it does, and expresses that view in “Does Quantum Physics Make it Easier to Believe in God?” at the BQO site. Personally, I think he is talking nonsense.
Barr even admits to some difficulties with arguing what his title says:
Not in any direct way. That is, it doesn’t provide an argument for the existence of God. But it does so indirectly, by providing an argument against the philosophy called materialism (or “physicalism”), which is the main intellectual opponent of belief in God in today’s world.
As it happens, I recently posted my own reasons for not being a materialist. And those reasons had nothing at all to do with whether there is a God or whether there is such a thing as the supernatural.
Materialism is an atheistic philosophy that says that all of reality is reducible to matter and its interactions.
That’s pretty much the view of materialism that I disagreed with in my post, the idea that everything is reducible to matter. But it is the reductionism, not the atheism, that I see as misguided. I see “atheistic” in Barr’s definition as a throwaway word. If you eliminated that word, it would not change anything. But theists like to put in such throwaway words, because they raise the passions of the theists who are their primary audience.
It [materialism] has gained ground because many people think that it’s supported by science. They think that physics has shown the material world to be a closed system of cause and effect, sealed off from the influence of any non-physical realities — if any there be.
I am always puzzled by arguments about cause and effect. It should have already been obvious to Newtonians, that every event has infinitely many causes and in turn causes infinitely many effects. The idea of discrete causes with discrete effects is naive, and it did not require QM to tell us that.
The meaning of “cause” is vague and often argued. Hume thought that causation was the same as constant conjunction. I am more inclined to say that what we mean by “cause” comes from our human experience of what we can cause by our own actions. And what makes an action our own is already controversial, as the many debates on free will illustrate.
Fortunately, science can get by without a precise meaning for “cause”. We mention causes in our informal descriptions, but the term “cause” does not show up in the equations.
Barr goes on to talk about the probabilistic nature of QM. And that leads to:
This is where the problem begins. It is a paradoxical (but entirely logical) fact that a probability only makes sense if it is the probability of something definite. For example, to say that Jane has a 70% chance of passing the French exam only means something if at some point she takes the exam and gets a definite grade. At that point, the probability of her passing no longer remains 70%, but suddenly jumps to 100% (if she passes) or 0% (if she fails). In other words, probabilities of events that lie in between 0 and 100% must at some point jump to 0 or 100% or else they meant nothing in the first place.
Sigh! Such confusion. Unfortunately, confusion about probability is very common.
I take the view that probability theory is a part of abstract mathematics. And in mathematics, we are always dealing with abstractions rather than “something definite.” Much confusion results, when people assume that probabilities are things that exist in the real world. The proper way to use probability, as I see it, is to think of us as using a mathematical model (in this case, a probabilistic model) of something in the real world. To use Barr’s example, to say that Jane has a 70% chance of passing the French exam is to posit that as an assumption in the mathematical model we are using. Our modeling might be poor, of course, in which case we might come to mistaken conclusions. Our use of “probability” in ordinary conversation tends to be quite casual and often based on poor assumptions. Serious arguments that are based on probability should be expected to flesh out the full details of the mathematical model being used.
Moving on in Barr’s post:
But what if one refuses to accept this conclusion, and maintains that only physical entities exist and that all observers and their minds are entirely describable by the equations of physics? Then the quantum probabilities remain in limbo, not 0 and 100% (in general) but hovering somewhere in between. They never get resolved into unique and definite outcomes, but somehow all possibilities remain always in play. One would thus be forced into what is called the “Many Worlds Interpretation” (MWI) of quantum mechanics.
Hmm, no, one would not be forced into such an interpretation. Another alternative is the anti-realist approach which, roughly speaking, says that the equations of QM have excellent predictive power, so we find them useful. But we should be cautious about trying to interpret every term in the equation as referring to something real. And that anti-realist view is quite consistent with taking probability as a term in mathematical models, rather than as something real.
The upshot is this: If the mathematics of quantum mechanics is right (as most fundamental physicists believe), and if materialism is right, one is forced to accept the Many Worlds Interpretation of quantum mechanics. And that is awfully heavy baggage for materialism to carry.
If, on the other hand, we accept the more traditional understanding of quantum mechanics that goes back to von Neumann, one is led by its logic (as Wigner and Peierls were) to the conclusion that not everything is just matter in motion, and that in particular there is something about the human mind that transcends matter and its laws.
And that is where Barr finds God in QM. But he is jumping to conclusions. From “not everything is just matter in motion” one cannot conclude “there is something about the human mind that transcends matter and its laws.”
In my earlier post on materialism, I gave the example of chairs, as something that is not precisely definable in purely materialistic terms. In particular, we cannot give a precise definition of “chair” in terms of matter in motion. But there is nothing transcendent about chairs, nor about our ability as humans to recognize chairs. It is merely that chairs are a social and cultural construct. That we call something a chair grows out of how we use in and our traditions about using chairs. If I take a particular chair, say the one that I am sitting on, then the laws of physics do apply to that chair as a physical object. They don’t apply to it as a chair, because “chair” is not a term in the laws of physics. There no transcendence. There is only a need to be careful to avoid confusion.
Shakespeare wrote “all the world’s a stage” and in a way, it is. Much of what we deal with in our everyday lives are social-cultural constructs. Think of things such as money, football games, highways, soap operas. Each of those has a physical component, but also depends on our cultural traditions of use. Science talks only of the physical component, but it would be silly to assume that there is something unnatural or transcendent about a football game or a soap opera.