It has been found in mice that the anesthetic xenon’s potency across its many isotopes varies depending on the spin property of that particular isotope, with no other atomic or molecular properties being able to account for this difference in potency. The findings from Li [Li et al, 2018] which demonstrate that spin can significantly affect anesthetic potency seems to be supporting evidence that consciousness is related to quantum effects. Spin is intrinsically a quantum property – if anesthetic potency is dependent on variations of spin, then it seems to implicate that quantum effects must be included in the mechanism of xenon’s anesthetic interaction to disrupt consciousness. However, before we can make the claim that this concretely demonstrates that consciousness must necessarily involve quantum effects, this mechanism needs to be further explored, as its influence on consciousness could be direct or indirect.

To elaborate, if all classical mechanisms were ruled out and the anesthetic interaction could only be explained by an innately quantum mechanism (between spin and an existing quantum system such as the microtubule), then there still would be a handful of different mechanisms and properties under the general category of quantum physics that could potentially be affected and correspond directly with phenomenological consciousness being disrupted (such as spin, a superpositioned state, entanglement, or collapse of the wave function). Experimental evidence may prove that consciousness necessarily involves quantum phenomena, but proving exactly which phenomena is a different question.

On the other hand, the debilitating effect on consciousness could be more indirect, meaning quantum spin could disrupt a pre-requisite process that is indirectly necessary for creating the conditions required for a more classically based consciousness to take place. Theoretically, there’s also the possibility that the exact mechanism which causes this spin-based disruption to occur might be understood as a classical interaction. For example, it is well known to physicists that an atom’s spin and ‘magnetic moments’ are interrelated properties – as described by the Dirac equation – meaning that a classical magnetic field can be produced by the quantum angular momentum of its charged particles [Dirac, 1928; Griffiths, 2005]. A potential mechanism could then be a xenon isotope’s spin generating a disruptive ‘magnetic moment’, which could classically impact the natural EMR frequencies oscillating in microtubules through this magnetic force – an interaction that would be akin to the underlying processes that cause the “Zeeman effect” [Griffiths, 2005]. Another possibility could be that this same magnetic process instead detrimentally impacts the coherence and binding of ordered water molecules to a microtubule’s inner lumen – a property which has previously been found to play a vital role in giving microtubules the conductivity required for their capacity to host electromagnetic radiation within its filamentary structure [Sahu & Bandyopadhyay et al, 2013a].

These theoretically supposed indirect ways in which quantum spin could impact consciousness through classical means however don’t withstand the realities of existing experimental evidence. If this disruption (in either case of the above examples) were due to the effects of magnetism, then one would predict that spin half (½) particles – which behave as fermions and create ‘magnetic moments’ as opposed to integer-spin bosons which don’t possess this same magnetic quality [Dirac, 1928; Griffiths, 2005] – would have a higher anesthetic potency due to their intrinsic magnetic force; this isn’t the case. In the xenon study, the fermionic isotopes had a lower anesthetic potency than their bosonic counterparts [Li et al, 2018]. This provides supporting evidence that classical magnetism isn’t implicated in this specific mechanism of anesthesia, as the reverse of the prediction is true. 

So, what is the mechanism that would describe why bosonic xenon isotopes with spin 0 are more aesthetically potent than fermions? My other post here demonstrates that this must be a quantum-on-quantum interaction, showing that consciousness itself is a quantum-based system.