← Evidence briefs

Quantum biology and consciousness

What this gives us: a warning. Five red flags for "quantum" claims, including the flag against dismissing it all as woo. And an open question: if consciousness needs quantum physics, classical AI is ruled out by its hardware, whatever it says.

2026-10-02

Checked by our internal skeptic review; corrections welcome.

This brief checks five commonly cited examples. Brackets show how each source was read.

Most sources were read at abstract level only, so every finding here is provisional until the full text is checked.

1. What quantum biology has shown

• DNA proton tunneling is supported by models but has not been measured in cells. Löwdin proposed it in 1963 [metadata only]. Slocombe, Sacchi and Al-Khalili (2022) calculated that tunneling far outweighs classical hopping in one base pair [abstract].
• Enzyme hydrogen tunneling is well supported. Klinman and Kohen (2013) review it [abstract]. Masgrau, Scrutton and colleagues (2006) found one reaction dominated by tunneling, noting: "The role of long-range coupled motions in promoting tunneling is controversial." [abstract]
• Long-lived photosynthetic coherence has largely been walked back. Engel et al. (2007) reported long-lived electronic coherence at 77 K, far colder than life [abstract]. At room temperature, Duan et al. (2017) found it fades in about 60 femtoseconds and saw no sign of a biological role [abstract]. Cao et al.'s 2020 review says the long-lived signals come mostly from vibrations [abstract].
• Radical-pair magnetic sensing in birds is a leading idea, but we found no source showing it at work in living birds. Xu and colleagues (2021) showed that robin cryptochrome 4 is magnetically sensitive as purified protein in the lab [abstract].
• We found no experiment testing DNA entanglement communication. We found theory papers only. One related test we saw only as a search snippet, between a person and cultured cells, did not test DNA. Not finding a study does not prove none exists.

2. Quantum theories of consciousness

Orch-OR (Penrose and Hameroff) says consciousness arises from quantum processes in neuron microtubules [Hameroff & Penrose 2014, abstract].

• The core critique is still disputed. Tegmark (2000) estimated that quantum states in the brain decay within about 10⁻¹³ to 10⁻²⁰ seconds, far faster than nerve signals [abstract]. Hagan, Hameroff and Tuszynski (2002) argued that revised assumptions give 10⁻⁵ to 10⁻⁴ seconds [abstract].
• Donadi et al.'s Gran Sasso test (Nature Physics 2021) narrows the physics. "This rules out the natural parameter-free version of the Diósi–Penrose model." [abstract] That is one collapse model, not all of Orch-OR.
• Kalra et al. (2023) found unexpected effects in lab protein. Energy spread about 6.6 nm along microtubules, and two anesthetics reduced it [abstract]. [OUR REASONING] This is not evidence of quantum computing or consciousness. Hameroff and Penrose are co-authors.
• Babcock et al. (2024) reported collective light emission in tryptophan networks, from theory and lab measurements [abstract]. Its abstract claims nothing about consciousness.
• A Wiest lab study (eNeuro 2024, first author Khan) tested rats. "EpoB-treated rats took an average of 69 s longer to become unconscious as measured by latency to LORR." [abstract] "Unconscious" means losing the righting reflex. [OUR REASONING] The drug could act through ordinary biology.
• Fisher (2015) proposed that phosphorus spins in "Posner molecules" could act as brain qubits [full text, arXiv]. We did not check whether its proposed tests were run.

3. What this means for AI

[OUR REASONING] If consciousness requires particular quantum physics, today's classical digital AI would be ruled out on hardware grounds. That holds whatever its self-report says or its cognition shows. Quantum computers remain a separate open question. If consciousness does not require quantum physics, other theories stay in play, both those tied to biology and those that are substrate-neutral. Neither outcome alone settles sentience or moral status.

4. Red flags to watch for

The same five flags are on How we check a claim, which links back here.

• Watch for "quantum" used to mean mysterious. Ask which effect is meant.
• Watch for a jump from "a quantum effect exists in biology" to "quantum explains consciousness." Enzyme tunneling says nothing about experience.
• Watch for coherence treated as entanglement, and entanglement treated as communication. All three differ.
• Watch for "proven" said about one study, a lab-protein result, or a model. Say "one study found" instead.
• Watch for 'quantum' dismissed as woo across the board. Some quantum effects in biology, like enzyme tunneling, are well supported. Judge each claim on its own evidence.