Physics Violations

Overview

Almost all functionalist theories associate consciousness with a pattern distributed across time. To do so, they must invoke a framework beyond contemporary classical or quantum physics whose fundamental equations are all non-Markovian, i.e. based on the current state only. In other words, they rely on current physics being invalid and arguably should focus their efforts on developing and testing novel physics, rather than speculating about consciousness.

For instance, a global workspace algorithm must keep track of where information came from in individual modules, so that this insight remains present when broadcasting the information in the future, otherwise we would not know what type of broadcasts 'qualify' for consciousness or not. However, the fundamental equations of relativity and quantum field theory do not create links to historic events like this. Future states depend only on the current state and the equations governing their evolution. Wherever that information is to be 'kept track of', it lies outside the understanding of physics.

Finding patterns within the historic causal graph is a computational problem, and as such, it requires access to the data in which those patterns exist. That would mean something in nature must have access to all of the historic interactions that need to be considered. An adjacent concern is that actually finding complex patterns in causal graph maps to the subgraph isomorphism problem, a computationally challenging problem to solve in the general case (NP-complete). Where does this computation take place in the proposed physical system? If the system embodies it, in some analogue computing sense, this requires explaining and likely introduces substrate dependencies that conflict with traditional views of functionalism.

Responses

But contemporary physics does contain non-Markovian equations - perhaps the functions of consciousness are related to those. For instance, equations governing viscoelastic materials make references to past events over various historic intervals, and collision integrals introduce memory kernels in the Boltzmann equation.
BUT: All non-Markovian in contemporary physics are non-fundamental. They represent simplifications of fundamental equations, such as Maxwell’s equations for electromagnetism, Einstein’s equations for relativity, and the broader framework of classical field theory in classical physics, or the Klein-Gordon and Dirac equations of Quantum Field Theory. All the fundamental theories are Markovian, and science treats these fundamental theories as a deeper truth closer to the ontological reality.
Non-Markovian equations emerge only as coarse-grained simplifications. Such references to past events are only an 'epistemic' form of memory, where we, as modelers, need to keep track of history because we've averaged out microstates. There is no true ontological memory defined in the equations of contemporary physics, where the universe itself remembers past states.
Perhaps consciousness is fundamentally outside the fundamental equations of physics. It is a different type of phenomenon - something strongly emergent or something spiritual in some way.
PERHAPS, BUT: Such extraordinary claims require extraordinary evidence. Unless consciousness is epiphenomenal and illusory, in which case there isn't anything meaningful to emerge anyway. If consciousness is a meaningful phenomenon, it must find its roots somewhere in the equations of physics or a different sort of world is being posited to our best current understanding. This is an avenue to pursue, but must acknowledge the boldness of its claims and make them explicit, e.g. in what sense a different form of causality or ontology is envisioned vs contemporary physics, what different predictions are made relative to those equations.
We know contemporary physics is incomplete, e.g. there is no established reconciliation of quantum physics with gravity. Perhaps the true underlying theory, if we ever get there, will be shown to be Markovian in nature, providing a realist underpinning to functionalist theories of consciousness. For instance, perhaps particles somehow carry their history of past interactions with them as they travel.
PERHAPS, BUT: If this is the argument, functionalists should be explicit that their claims specifically contradict contemporary laws of physics and rely on future novel insights. For instance, if particles carry their history, where do they do this? If they carry information within the framework of physics, then that information must be stored physically. But particles are too simple to store an ever-increasing volume of information describing every single past interaction and too simple to conduct computations over it to look for particular patterns. They are literally too light to encode the weight of this information. If this notion is true, where are the predictions and incredible technologies based on leveraging it for data storage...

Overview

Responses

Further reading