Ever since the indeterministic and “non-local” aspects of Quantum Mechanics (QM) were discovered by scientists, some have theorised that such physics could underlie the human brain, thus either accounting or allowing for free will (contra classical and deterministic models of the brain) and other aspects of the mind that appear to transcend a mere sequence of local and causally-linked biochemical reactions. J. C. Eccles did this in the 1950s. The discussion of his ideas and others of the time by Dr Eric Mascall in Christian Theology and Natural Science (1956), when compared with relevant works of today, shows that in many ways little has changed in this area of study. Others teams of renowned and respected scientists have posited similar ideas since then, including L. M. Ricciardi and H. Umezawa; Roger Penrose and Stuart Hameroff; Mari Jibu and Kunio Yasue; Karl H. Pribram, George Miller and Eugene Galanter; and Henry Stapp, Jeffrey Schwartz and Mario Beauregard.
QM involves “indeterministic” or “coherent” effects in matter. This means, among other things, that probabilistic wave-like interference leads to particles no longer being thought of as billiard-ball-like objects with specific positions and velocities. Instead, they have probability distributions in space and time, and so their interactions can never be completely predicted. Weirder still, the whole range of “possible” properties at one point in time contribute to the probability of particular properties occurring at a later point in time, but only one possible configuration ends up being observed or measured at any point in time! This latter process is called “state reduction” or “waveform collapse”. The former process, with its fuzzy, unresolved picture of reality and accompanying “Schrodinger equation”, is firmly deterministic. (This is often not realised.) Nevertheless, the unpredictability abovementioned is not merely a limitation of measurement. The “later” (reduced) state is genuinely not exactly or specifically determined by the “former” state.
The main objection to QM mind-brain propositions is based on the purportedly insufficient size of these effects relative to classical ones in the brain, due to its high temperature (and thus its hegemony of thermalising interactions) leading to constant and widespread “decoherence” of atomic scale QM fuzziness. However, apart from this claim being debatable, it ignores the possibility that even vanishingly small QM effects could have larger effects if the brain is partly governed by “chaos-style” physics, i.e., the “butterfly effect”. That some element of this might be occurring in the brain is suggested by two things. One, the non-linear operation of neuronal interactions and sequences due to their “web-like” patterns. Two, the apparently unpredictable, spontaneous and trans-rational aspects of consciousness such as creativity. However, it must be noted that chaos theory is still classical and deterministic in itself, so it cannot explain or allow for free will on its own. Also, it obviously can have little or no contribution to normal, rational thought, since the latter inherently requires predictable and consistent outcomes not sensitive to “insignificant” initial variations in input. Nevertheless, wherever rational reflection is not the sole component of decision-making, QM may provide a sufficient “loophole” for physical indeterminism without any empirically detectable “counterflow” (i.e., physical events not explicable in terms of purely physical laws of cause and effect). Of course, such possibilities would not automatically imply free will in the fullest sense, since they do not necessarily involve a personal agent determining an outcome (first in the brain), but instead may imply nothing whatever is responsible for determining the specific outcome or “choice” as it subsists in the brain. This brings us to the two separate categories of QM mind-brain theories.
The QM mind-brain theories of Penrose and others who think in the same vein make consciousness a Quantum Effect. On the other hand, that of Stapp and others makes it an independent Cause, a non-physical “observer” or “measurement” phenomenon which itself creates the state reduction (or waveform collapse), making certain outcomes more likely via “attention density” and the concomitant Quantum Zeno Effect. Stapp refers to the QM physical evolution as Process 2, and the reduction of the quantum superposition of possible states to one observed state as Process 1. This theory is far less materialistic and reductionist and so more “threatening” to the average scientist. It also does not explicitly answer the question of how consciousness “decoheres” or reduces a QM brain state non-physically, given that all other such events require the interaction of photons etc. Instead it seems to claim that all other examples of reduction are not really real till we consciously observe them! While strictly non-falsifiable, as all possible falsifications would require conscious observation, this idea seems very strange, recalling Einstein’s question to a colleague, “Do you really believe the Moon is not there till you see it?”
Mind you (pun intended), the common modern alternative claim that environmental decoherence makes a real, as opposed to apparent, process of consciously-observed (or caused) state reduction superfluous only makes sense if we assume the truth of the many-worlds hypothesis, which is arguably just as non-falsifiable and a priori unlikely. (The many-worlds hypothesis says that state reduction is an illusion, with the deterministic Schrodinger equation describing the totality of a real, fuzzy universe. The only reason we see one specific state at a time is that we as observers are part of each possible state and can thus only be conscious of the one we are in. Hence, there are infinitely many apparently reduced states and versions of us, all unobservable in principle!) Also, quantum decoherence doesn’t really get rid of QM fuzziness, it just broadens it to include the whole universe and all its conscious observers. But why then is each observer conscious of a discrete, substantial self-unity if every universe/observer QM state is not really a “closed off” particular state of affairs but a point on a continuous probability density distribution? To put it another way, since every apparently reduced and particular state that is observed corresponds to only one “point” in a real continuous probability density distribution of states, what is the significance of the probability density itself at each point within that experienced “reduced” state? Since all possible situations within the “omnium” — to quote Penrose’s term for the quantum superposition of all states underlying the many worlds — are in some sense “realised”, what differentiates the very low from the very high probability situations for observers within them? If the answer is nothing, then the only empirical significance the probability distribution has within the environmental-decoherence/many-worlds model is in predicting the chances of “what happens next”. Except the answer to this appears to be “every possible outcome” within the omnium. It may just be my lack of imagination, but this whole approach seems flawed and ontologically promiscuous.
If it so happened the Stapp thesis was basically correct, then its deeply counterintuitive aspect, that state reduction only occurs due to human consciousness, could be ameliorated by the Christian world-view, which posits pre-human and pre-animal consciousness in God and the Angels. Indeed, the common tradition in Christian theological speculation that non-embodied spirits such as angels have some kind of ongoing role in oversight of Creation would then be connected to a particular mechanism whereby they could do this in an active way, yet one that did not involve any counterflow. Since these spirits, unlike humans, would not be limited in themselves by “Process 2” interactions (i.e., those purely in accordance with the deterministic evolution of QM’s Schrodinger equation) as they are not reliant on a physical brain, they might have greater freedom in specifying state reduction by “Process 1” than that given by the Quantum Zeno effect. This would give them enormous freedom to “intervene”, though such intervention would never be empirically verifiable as “miraculous” counterflow unless the sum of their actions deviated in a statistically significant way from QM’s predicted probability distributions. Given that they would be likely to act in a maximally efficient way and that small interventions at the right time and place can have great effect, such observable deviation would be a priori unlikely normally.
One major problem with the theory of Stapp et al., as it applies to free will, is their explanation of Libet’s experiments, which detected unconscious precursors to the consciousness of making a choice. They imply that the conscious choice retrospectively decoheres the brain process and thus effectively causes the prior subconscious process! The problem with this is that the very detection in real time of the prior process has already decohered or reduced the system, leaving no coherence for the conscious will to play with.
However, there are other points about Libet’s experiments that undermine the inference that conscious volition is illusory, including his own observation that conscious will can still over-rule the subconsciously prepared action. This has been amusingly referred to as “free won’t”. There is an even more fundamental problem with Libet’s experiments, the host of similar ones that have followed, and the conclusions drawn from them. They all require preceeding instructions to be understood by participants, and they all involve the choice of timing certain simple actions, such as flexing a wrist or pressing a button, which had no great intrinsic significance. That means the acts of will tested were trivial, relatively unreflective and so effectively arbitrary and spontaneous, and without serious consequence. They were not based on prior complex reasoning and reflection, nor were they intrinsically meaningful, and they were known not to have important consequences. In other words, the human subjects were basically being asked to act like random number generators and were not required to engage the highest mind or brain functions. Therefore, the fact that these particular decisions were largely independent of the conscious mind does not necessarily tell us much about conscious volition generally. And note that the subconscious “urges” that were determinative would not have happened without the prior conscious understanding of instructions given by the experimenters. So, these results prove very little.
In conclusion, there is nothing modern physics has discovered to prove the mind is nothing more than a mechanistic “epiphenomenon” of brain function or that free will is impossible. On the contrary, it has opened up new areas for exploration and undermined materialistic and deterministic accounts of human nature.