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Hameroff, the author, also subscribed to the quantum brain hypothesis, along with Roger Penrose; an idea which was widely dismissed as wildly implausible, if I

Hameroff, the author, also subscribed to the quantum brain hypothesis, along with Roger Penrose; an idea which was widely dismissed as wildly implausible, if I recall correctly. The topic itself is fascinating though.

igorlev 14y ago
Anytime I hear microtubules I instantly think Penrose and The Emperor's New Mind
ktizo 14y ago
It was dismissed as implausible at the time due to the assertion that there was no evidence for biological processes being anything other than classical. Now there has been found a wide range of quantum biological effects, from the action of chlorophyll to the mechanism of our sense of smell, so it seems a lot less implausible than it used to.
- andreasvc 14y ago
  I think it is still implausible because of the vast difference in scale between quantums and neurons, several orders of magnitude. Quantum effects don't manifest themselves on a macro-scale. I don't know precisely how quantum effects help our sense of smell or with photosynthesis as has been claimed, but I reckon it has to do with localized effects. The idea that quantum effects across the brain work in concert to create a single, global consciousness is quite a bit more far fetched, if not preposterous. But if you have a particular reference saying it's considered more plausible nowadays I'd love to hear about it.
  - ktizo 14y ago
    Quantum effects don't manifest themselves on a macro-scale. We certainly used to think so, not so much any more. http://physicsworld.com/cws/article/news/2003/sep/03/entanglement-goes-macroscopic http://physicsworld.com/cws/article/news/2003/sep/03/entangl...
Dn_Ab 14y ago
It is still widely dismissed. And while coherence seems to be relevant for a particular stage of energy conversion in photosynthesis and also in allowing sensitivity to magnetic fields, the mechanisms for leveraging these are incidental. They are used passively to achieve an effect and not actively to perform computations as would be required for Penrose's hypotheses. To claim the brain leverages quantum effects at biological scales is going far but still plausible. But to say that quantum computations are going on in the brain and are expressed at the level of thinking we acheive (evinced by claiming that we are not Turing machines), that is something that would require a lot of data to support (something that this theory sorely lacks). Much of what we know about quantum mechanics and neurobiology would have to be redressed. Indeed if such were true there would be indirect evidence - I expect we would find quantum mechanics, heck ordinary probability theory, more intuitive for example . Far more interesting are the epigenetic like effects that occur in memory formation.
- andreasvc 14y ago
  > claiming that we are not Turing machines There are independent arguments for that position, namely that it's quite likely that the brain does not everywhere operate digitally, with well-defined discrete states. And even if it did in a trivial sense because the whole of physics operated that way it wouldn't really help with describing how the brain works (wrong level of abstraction).

igorlev 14y ago

Anytime I hear microtubules I instantly think Penrose and The Emperor's New Mind

ktizo 14y ago

It was dismissed as implausible at the time due to the assertion that there was no evidence for biological processes being anything other than classical. Now there has been found a wide range of quantum biological effects, from the action of chlorophyll to the mechanism of our sense of smell, so it seems a lot less implausible than it used to.

andreasvc 14y ago
I think it is still implausible because of the vast difference in scale between quantums and neurons, several orders of magnitude. Quantum effects don't manifest themselves on a macro-scale. I don't know precisely how quantum effects help our sense of smell or with photosynthesis as has been claimed, but I reckon it has to do with localized effects. The idea that quantum effects across the brain work in concert to create a single, global consciousness is quite a bit more far fetched, if not preposterous. But if you have a particular reference saying it's considered more plausible nowadays I'd love to hear about it.
- ktizo 14y ago
  Quantum effects don't manifest themselves on a macro-scale. We certainly used to think so, not so much any more. http://physicsworld.com/cws/article/news/2003/sep/03/entanglement-goes-macroscopic http://physicsworld.com/cws/article/news/2003/sep/03/entangl...

Dn_Ab 14y ago

It is still widely dismissed. And while coherence seems to be relevant for a particular stage of energy conversion in photosynthesis and also in allowing sensitivity to magnetic fields, the mechanisms for leveraging these are incidental. They are used passively to achieve an effect and not actively to perform computations as would be required for Penrose's hypotheses. To claim the brain leverages quantum effects at biological scales is going far but still plausible. But to say that quantum computations are going on in the brain and are expressed at the level of thinking we acheive (evinced by claiming that we are not Turing machines), that is something that would require a lot of data to support (something that this theory sorely lacks). Much of what we know about quantum mechanics and neurobiology would have to be redressed. Indeed if such were true there would be indirect evidence - I expect we would find quantum mechanics, heck ordinary probability theory, more intuitive for example . Far more interesting are the epigenetic like effects that occur in memory formation.

andreasvc 14y ago
> claiming that we are not Turing machines There are independent arguments for that position, namely that it's quite likely that the brain does not everywhere operate digitally, with well-defined discrete states. And even if it did in a trivial sense because the whole of physics operated that way it wouldn't really help with describing how the brain works (wrong level of abstraction).