---
title: 'The Quantum Brain Theory Nobody Is Talking About'
source: 'https://youtube.com/watch?v=q2T6RMkIyHQ'
video_id: 'q2T6RMkIyHQ'
date: 2026-08-04
duration_sec: 367
---

# The Quantum Brain Theory Nobody Is Talking About

> Source: [The Quantum Brain Theory Nobody Is Talking About](https://youtube.com/watch?v=q2T6RMkIyHQ)

## Summary

This video explores the hypothesis that quantum effects, specifically nuclear spins in phosphorus-containing molecules, might play a role in consciousness. The presenter reviews recent scientific papers that lend some credibility to the idea, while expressing personal skepticism.

### Key Points

- **Quantum consciousness idea** [00:00] — The idea that quantum physics links to consciousness dates back a century, but most physicists reject it. However, the mechanism of consciousness is unknown, leaving room for quantum effects.
- **Matthew Fisher's proposal** [00:30] — In 2015, physicist Matthew Fisher proposed that the brain uses nuclear spins for quantum information processing, specifically phosphorus-31 in Posner molecules, which can protect quantum states in biological environments.
- **Comparison with Penrose-Hameroff** [01:14] — Fisher's idea is cleaner than Penrose and Hameroff's microtubule theory because it offers a mechanism: entangled spins in Posner molecules could release calcium ions in a correlated way, influencing neural signaling.
- **Quantum coherence times** [02:08] — Calculations for how long phosphate molecules retain quantum properties in the brain: Fisher estimated 3 weeks, corrected to half an hour, and the latest calculation suggests a few hundred seconds.
- **Lithium isotope experiment** [04:04] — A paper found that chemical reactions of phosphate molecules with lithium isotopes depend on nuclear spin, lending credibility to the idea that nuclear spin plays a role.
- **Psychedelics and consciousness** [04:37] — Another paper conjectures that psychedelic drugs work by generating conditions for Posner molecule formation, potentially linking directly to consciousness, though without direct evidence.
- **Presenter's skepticism** [04:55] — The presenter admits he thinks the idea is '100% bullshit' but cannot scientifically explain why, and notes that no one has established that Posner molecules exist in the brain.

### Conclusion

While the quantum consciousness theory is intriguing, the presenter remains skeptical due to lack of evidence and the implausibility of long coherence times. However, the brain's chemistry is still poorly understood, and phosphorus might play a role.

## Transcript

That there’s a link between quantum physics  and consciousness is an idea that dates   back to the very early days of quantum  physics, a century ago. Most physicists   today don’t believe this link exists and  I understand the reservation. Then again,  
it’s true that we don’t actually know how the  human brain creates conscious experience so   it is possible that quantum effects do play  a role. Interestingly, we’ve recently seen   new evidence supporting this idea, and no  it’s not microtubules. Let’s have a look.
This idea goes back to physicist Matthew  Fisher. In 2015, he proposed that the   brain might use nuclear spins for quantum  information processing. A nuclear spin   is a quantum property of an atomic nucleus,  different from the electron spin. Concretely,  
Fisher thinks the spin relevant for  consciousness is that of phosphorus-31. In the human body, some phosphorus appears in  clusters called Posner molecules. These are  
interesting because they can protect the  nuclear spins from the noisy biological   environment. This means they could  maintain their quantum properties,   which is usually difficult in warm, wet,  and messy environments like living tissue.
This is the major issue with all these  ideas that consciousness has something   to do with quantum effects: That you need a  way to explain why the quantum effect can be   present in the first place. Roger Penrose and  Stuart Hamaroff say the microtubules do it.  
Fisher has the idea it’s the nuclear  spin of these molecule groups. That,   I have to admit, is a much cleaner  way to encode quantum behaviour. And in contrast to Penrose and Hameroff,  he also has an idea for what it’s got to  
do with consciousness. Fisher says that if  two of these molecules carry entangled spins,   and later break apart in different places,  they could release calcium ions in a correlated  
way. Calcium is important for signaling  between neurons. So, in principle, quantum   correlations could influence neural activity. In principle, ok, but what about reality?  
In one recent paper, a group of scientists  did a calculation for how long these phosphate   molecules can retain quantum properties in the  brain. Fisher himself estimated about 3 weeks  
which seems somewhat ridiculous. A different  group later corrected this to half an hour.   The new calculation now says something in the  range of a few hundred seconds. So this is not  
proof that there is a link between quantum  effects and brain activity in general or   consciousness in particular, but that maybe  the idea is not as crazy as we once thought. Stop losing money on a pile of separate AI tools.  Quick pause because today's video sponsored by  
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In another paper, a group of scientists  found that chemical reactions of this   phosphate molecule with lithium isotopes depend  on the nuclear spin. The relevance of this is   not directly about brain signalling,  but it lends credibility to the idea  
that the nuclear spin plays a role, probably  because it interacts with the electron spin. And then there is a third paper whose authors  conjecture that these phosphate molecules are   the reason why psychedelic drugs act the  way they do, which would basically be a  
direct link to consciousness. They have no  direct evidence for this, but they argue that   the drugs generate the right conditions for  these particular molecule clusters to form. What are we to make of this? Ok. Let me be honest.  I think this is 100% bullshit. The problem is,  
I can’t tell you why. I just look at these papers  and think it sounds like bullshit. And then I   think this is not a very scientific reaction is  it? So I try to be open minded and tell you about   it. But well, this is what I think: It’s bullshit. There is also the issue that so far no one  
has actually established that these particular  molecules are present in the human brain to begin   with. This isn’t as easy to find out as you’d  think. We know that they exist in human bones,   but in the brain they would be produced  temporarily to take part in some signaling  
process. So you can’t figure out whether they  were present from, you know, slicing up people's   brains after they’ve died. Also kind of raises  the questions why my bones aren't conscious.
So is the origin of consciousness in  some quantum processes? Probably not   in this simple sense. But is the  brain doing chemistry we still   do not fully understand? Absolutely. And  if phosphorus turns out to be important,  
I apologise in advance to everyone who thought  the soul would be made of something more poetic. Thanks for watching. See you tomorrow.