Thanks to Joe Webster and Tom Lovejoy for setting the ball rolling on this classic question. Here are a few thoughts to keep it in play. Do add your own … Remember: I’m no expert on this, just a fellow investigator.
Joe asked: “Does the lack of determinism in quantum mechanics allow for the possibility of choice? If so, how can the human process of making a decision affect the outcome of a “measurement”, in the sense of quantum physics?”
Tom commented: “I have been struggling with this question for a long time. If God knows everything, including the future and everything that will happen, doesn’t that make free will impossible? And would that mean that we live in a deterministic universe, where our actions and choices are purely the result of stimulus and other things (a butterfly flapping its wings on the other side of the planet, slightly changing the weather, making a raindrop splash into your eye and putting you into a bad mood… Etc)?
To start with Tom’s comments:
- in classical theology (going back to Augustine in particular), God’s knowledge is understood as being from outside time. so it is not “fore-knowledge” and does not prejudice our free will. A “block universe” cosmology, in modern terms, coheres with this.
- some more modern theology understands God as continually creating within time (“process theology”), in partnership with us. John Polkinghorne would espouse this view, and see God as voluntarily giving up his timeless omniscience in so doing – a “kenosis” like that shown in the incarnation.
- NB the butterfly example comes from chaos theory, and is in fact anti-deterministic I think. It describes how a small cause can have a great and apparently unconnected effect but this effect is unpredictable, certainly in terms of any feasible calculation, and probably in principle given that the system shows high complexity.
Now to go back to Joe’s question:
- I’m not a physicist, but my understanding is that those who study quantum mechanics are divided as to whether the world at quantum scale “really” is marked by superpositions and indeterminacy, or whether these are a consequence of our inability to observe it sufficiently well.
- In the latter case, the underlying reality is still classical, but we are not able to know it in the usual way, and need to use probabilistic methods etc. The issues about free-will are the same.
- In the former case, the underlying reality is indeed “open”. Our actions in measuring, like other interactions, resolve the open-nesses. So is this is a way in which our free-will can be exercised?
- I suspect that this is insufficient to allow for free-will, which requires a top-down agency as well as a bottom-up mechanism (or else it is just a case of one complex indeterminate system affecting another one). Polkinghorne here looks to David Bohm’s theory of “active information”, positing an actually existent “noetic” realm, which would include maths for instance, which allows the whole to have a causal effect on the parts in complex systems. This is far from worked-out as a theory, but is developed in scientific rather than philosophical terms. Theologically this would provide a correlative mechanism for free will and indeed divine providence.