[00:00] That there’s a link between quantum physics&nbsp; and consciousness is an idea that dates&nbsp;&nbsp; back to the very early days of quantum&nbsp; physics, a century ago. Most physicists&nbsp;&nbsp; today don’t believe this link exists and&nbsp; I understand the reservation. Then again,&nbsp;&nbsp;
[00:14] it’s true that we don’t actually know how the&nbsp; human brain creates conscious experience so&nbsp;&nbsp; it is possible that quantum effects do play&nbsp; a role. Interestingly, we’ve recently seen&nbsp;&nbsp; new evidence supporting this idea, and no&nbsp; it’s not microtubules. Let’s have a look.
[00:30] This idea goes back to physicist Matthew&nbsp; Fisher. In 2015, he proposed that the&nbsp;&nbsp; brain might use nuclear spins for quantum&nbsp; information processing. A nuclear spin&nbsp;&nbsp; is a quantum property of an atomic nucleus,&nbsp; different from the electron spin. Concretely,&nbsp;&nbsp;
[00:46] Fisher thinks the spin relevant for&nbsp; consciousness is that of phosphorus-31. In the human body, some phosphorus appears in&nbsp; clusters called Posner molecules. These are&nbsp;&nbsp;
[00:58] interesting because they can protect the&nbsp; nuclear spins from the noisy biological&nbsp;&nbsp; environment. This means they could&nbsp; maintain their quantum properties,&nbsp;&nbsp; which is usually difficult in warm, wet,&nbsp; and messy environments like living tissue.
[01:14] This is the major issue with all these&nbsp; ideas that consciousness has something&nbsp;&nbsp; to do with quantum effects: That you need a&nbsp; way to explain why the quantum effect can be&nbsp;&nbsp; present in the first place. Roger Penrose and&nbsp; Stuart Hamaroff say the microtubules do it.&nbsp;&nbsp;
[01:30] Fisher has the idea it’s the nuclear&nbsp; spin of these molecule groups. That,&nbsp;&nbsp; I have to admit, is a much cleaner&nbsp; way to encode quantum behaviour. And in contrast to Penrose and Hameroff,&nbsp; he also has an idea for what it’s got to&nbsp;&nbsp;
[01:44] do with consciousness. Fisher says that if&nbsp; two of these molecules carry entangled spins,&nbsp;&nbsp; and later break apart in different places,&nbsp; they could release calcium ions in a correlated&nbsp;&nbsp;
[01:56] way. Calcium is important for signaling&nbsp; between neurons. So, in principle, quantum&nbsp;&nbsp; correlations could influence neural activity. In principle, ok, but what about reality?&nbsp;&nbsp;
[02:08] In one recent paper, a group of scientists&nbsp; did a calculation for how long these phosphate&nbsp;&nbsp; molecules can retain quantum properties in the&nbsp; brain. Fisher himself estimated about 3 weeks&nbsp;&nbsp;
[02:24] which seems somewhat ridiculous. A different&nbsp; group later corrected this to half an hour.&nbsp;&nbsp; The new calculation now says something in the&nbsp; range of a few hundred seconds. So this is not&nbsp;&nbsp;
[02:38] proof that there is a link between quantum&nbsp; effects and brain activity in general or&nbsp;&nbsp; consciousness in particular, but that maybe&nbsp; the idea is not as crazy as we once thought. Stop losing money on a pile of separate AI tools.&nbsp; Quick pause because today's video sponsored by&nbsp;&nbsp;
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[04:04] In another paper, a group of scientists&nbsp; found that chemical reactions of this&nbsp;&nbsp; phosphate molecule with lithium isotopes depend&nbsp; on the nuclear spin. The relevance of this is&nbsp;&nbsp; not directly about brain signalling,&nbsp; but it lends credibility to the idea&nbsp;&nbsp;
[04:20] that the nuclear spin plays a role, probably&nbsp; because it interacts with the electron spin. And then there is a third paper whose authors&nbsp; conjecture that these phosphate molecules are&nbsp;&nbsp; the reason why psychedelic drugs act the&nbsp; way they do, which would basically be a&nbsp;&nbsp;
[04:37] direct link to consciousness. They have no&nbsp; direct evidence for this, but they argue that&nbsp;&nbsp; the drugs generate the right conditions for&nbsp; these particular molecule clusters to form. What are we to make of this? Ok. Let me be honest.&nbsp; I think this is 100% bullshit. The problem is,&nbsp;&nbsp;
[04:55] I can’t tell you why. I just look at these papers&nbsp; and think it sounds like bullshit. And then I&nbsp;&nbsp; think this is not a very scientific reaction is&nbsp; it? So I try to be open minded and tell you about&nbsp;&nbsp; it. But well, this is what I think: It’s bullshit. There is also the issue that so far no one&nbsp;&nbsp;
[05:12] has actually established that these particular&nbsp; molecules are present in the human brain to begin&nbsp;&nbsp; with. This isn’t as easy to find out as you’d&nbsp; think. We know that they exist in human bones,&nbsp;&nbsp; but in the brain they would be produced&nbsp; temporarily to take part in some signaling&nbsp;&nbsp;
[05:28] process. So you can’t figure out whether they&nbsp; were present from, you know, slicing up people's&nbsp;&nbsp; brains after they’ve died. Also kind of raises&nbsp; the questions why my bones aren't conscious.
[05:40] So is the origin of consciousness in&nbsp; some quantum processes? Probably not&nbsp;&nbsp; in this simple sense. But is the&nbsp; brain doing chemistry we still&nbsp;&nbsp; do not fully understand? Absolutely. And&nbsp; if phosphorus turns out to be important,&nbsp;&nbsp;
[05:54] I apologise in advance to everyone who thought&nbsp; the soul would be made of something more poetic. Thanks for watching. See you tomorrow.