65. Quantum Mechanics

but if I wasn't here documenting the story

would that mean that the plot did not exist?

Oh, would it not be absurd if there was no objective state?

What if the unobserved always waits, insubstantial,

till our eyes give it shape?[1]

The Copenhagen interpretation of quantum mechanics, proposed by Bohr, maintains, inter alia, that an entity is not “real” until it is observed by a conscious observer. This has lead to widely-held belief in physics that: 

In quantum theory physical reality is dependent on the observer and hence on human consciousness.[2]

This view derives from not distinguishing the domain of categorisable phenomena from the domain of categories created by observers in the process of categorising. If this distinction is recognised, then the Copenhagen interpretation becomes (less mysteriously): a phenomenon is not categorised until observed. It is not that physical reality is dependent on the observer, but that the categorisation of perceivable phenomena is dependent on the categorising process. The categorial identity of a phenomenon — of perceivable difference — requires interaction with a categorising system.[3]

The belief in the notion of nonlocality derives from the findings of multiply replicated experiments since Aspect (1982) which demonstrate that a property of one particle can depend on a property of another. If the particles in question are photons moving away from each other at the speed of light after a collision, then it is thought that there are only two alternative explanations: either there must be faster-than-light signalling between the particles, or the particles must be connected in some way. Since faster-than-light signalling is ruled out by the theory of Relativity, and would introduce a host of logical paradoxes, it is claimed that the experiment demonstrates that the notion that reality is separable into distinct localities is false — at least at the most fundamental level of the quantum. 

If the distinction is made between the domain of categorisable phenomena and the domain of categories, then such experiments can, instead, be understood as demonstrating findings about the categorisation process. For example, the experiments demonstrate that, at the most fundamental level known, tested by the most rigorous methods known, categories are relative: mutually dependent, mutually defining. Further, the Copenhagen interpretation of quantum mechanics might be taken to suggest that the domain of phenomena, of perceivable difference, has zones of uncategorisability, or of unresolvability.[4] That is, it may suggest that some phenomena, at least, are not categorisable until observed. 

Footnotes:

[1] Peter Hammill Our Eyes Give It Shape from Singularity (2007).

[2] Robinson (2005: 120).

[3] That is, a value is related to a phenomenal token by a categorising system, where each value is the carrier of one or more attributes (an instance of one or more categorial types).

[4] At least with known methods of detection and categorisation.

ChatGPT revised:

Our Eyes Give It Shape

but if I wasn't here documenting the story
would that mean that the plot did not exist?
Oh, would it not be absurd if there was no objective state?
What if the unobserved always waits, insubstantial,
till our eyes give it shape?
— Peter Hammill, Our Eyes Give It Shape (2007)

The Copenhagen interpretation of quantum mechanics, associated with Bohr, maintains — among other things — that an entity is not “real” until it is observed by a conscious observer. This has led to a widespread belief in physics that:

In quantum theory, physical reality is dependent on the observer and hence on human consciousness.[2]

This interpretation arises from a failure to distinguish between two domains: (i) the domain of categorisable phenomena — that is, perceivable difference — and (ii) the domain of categories constructed by observers in the act of categorising. If this distinction is made, the Copenhagen interpretation becomes less metaphysically troubling: not that physical reality depends on observers, but that categorisation — the attribution of type or value — does. A phenomenon is not categorised until it is observed.

That is, the categorial identity of a phenomenon — its identification as an instance of a type — requires interaction with a categorising system.[3] Observation is the act by which potential categorial values are collapsed into actual instances.

A similar confusion surrounds the interpretation of quantum nonlocality. Since the Aspect experiments (1982), it has been accepted that the value attributed to one particle can depend on the value attributed to another, even when the particles are spatially separated. If the two particles are photons moving apart at the speed of light following a collision, then only two explanations appear possible: either (a) faster-than-light signalling is occurring, or (b) the particles remain connected in some way. As (a) would violate Relativity and introduce paradox, (b) is taken to mean that reality is nonlocal — that separability is an illusion, at least at the quantum level.

But again, if we distinguish the domain of categorisable phenomena from the domain of categories, an alternative understanding emerges. These experiments can be understood as demonstrating constraints not on phenomena per se, but on the process of categorisation. Specifically, they show that at the most fundamental level tested, categories are relative — mutually defined, mutually dependent.

Further, the Copenhagen interpretation might be understood to imply that the domain of perceivable difference includes zones of uncategorisability — or at least zones where categorisation remains unresolved until interaction occurs.[4] Some phenomena, in other words, may not be categorisable — may not instantiate a value — until observed.

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Notes

[1] Peter Hammill, Our Eyes Give It Shape, from Singularity (2007).

[2] Robinson (2005: 120).

[3] That is, a value is related to a phenomenal token by a categorising system, where each value is the carrier of one or more attributes — an instance of one or more categorial types.

[4] That is, with current methods of detection and categorisation.