In 1935 Einstein, Podolsky and Rosen published a paper that is now known as the EPR paradox. Formally, an attempt to show that quantum mechanics is incomplete. In practice, the first statement of what would later be called quantum entanglement.
Einstein called it spooky action at a distance. He was convinced the phenomenon was an artefact, and that a deeper local theory with hidden variables stood behind quantum mechanics.
In 2015 Ronald Hanson's team at Delft University of Technology ran a loophole-free Bell test. Electrons in diamond defects, separated by 1.3 kilometres. No loophole left open — locality loophole sealed, detection loophole sealed. Result: Bell's inequality is violated. Local realism is dead.
A measurement, not a disputable news item. Since then it has been replicated in Vienna (Zeilinger), in Munich, at NIST. Same result.
What this does not imply
Nonlocality of quantum mechanics doesn't get you to: the brain is a quantum computer; consciousness is smeared across the universe via entanglement; you can "upload" a mind to the cloud or "tune into" a field. None of those follow from the result.
The standard interpretation error: take a real physical fact (entanglement is real) and bolt a speculation onto it (entanglement operates inside the brain), as if the first supports the second. It doesn't.
What this may imply
Roger Penrose and Stuart Hameroff, since the mid-90s, have been developing the Orch-OR hypothesis: coherent quantum states in neuronal microtubules, whose collapse is tied to moments of conscious choice. Most physicists were sceptical: at body temperature, decoherence should destroy any coherence in picoseconds.
In 2022 Jennifer Frisch (Trinity College Dublin), Monika Hirschak and Tristan Farrow (Purdue) published work showing that microtubules actually exhibit unusually long coherence times under physiological conditions. Far from a proof of Orch-OR. But the hypothesis is no longer ruled out on sight.
An interesting status: a theory that used to sit outside serious discussion now hangs in "testable speculation".
Tononi, IIT, and its problem
Giulio Tononi proposed a different approach — Integrated Information Theory. Consciousness, per Tononi, is a measure of the integratedness of a system, denoted Φ (phi). The more a system behaves as a whole rather than as independent parts, the higher its Φ.
The theory is elegant. Its main weakness is computational. The exact Φ of a system the size of a brain is uncomputable: complexity grows exponentially. Critics (Scott Aaronson) also point out something else: IIT makes strange predictions for artificial systems — for instance, that a simple logic-gate grid has consciousness above a human's. Tononi acknowledges the problem without abandoning the frame.
Normal territory for an honest theory. It makes predictions you can criticise.
What I think
Three levels of certainty.
Established: quantum mechanics is nonlocal (Delft 2015 and after). Information is physical (Landauer 1961, experiment 2012). Consciousness correlates with integrated brain activity, not with volume (Tononi and Tucson labs).
Preliminary: microtubules may sustain coherence longer than previously thought. Orch-OR becomes discussable, if still unproven.
Speculation: if gravity is emergent (Verlinde), the universe is a neural network (Vanchurin), and consciousness is integrated information (Tononi), then these three claims may be describing the same phenomenon from different angles. Precisely, speculation. Speculation you can start testing.
Quantum consciousness right now is a set of measurements, not a finished theory. Each of them, for now, is still alive.