Physics in Mind: A Quantum View of the Brain by Werner R. Loewenstein

Physics in Mind is a book about how to incorporate quantum mechanics in a coherent account of how the brain works. It is a laudable venture, but one prone to failure in the ambush of dualism that awaits those who try to explain the mind - a loose scientific concept - with quantum notions. And, even more problematically, those who try to explain consciousness with quantum mechanics. But let me start a few weeks ago.

I frowned when I was ap- proached to review Physics in Mind. Not because of the title, but because of the subtitle, A Quantum View of the Brain. Nevertheless I accepted the challenge, as I like to think that I am open to ideas, even those I think are not well formulated or wrong or that I do not understand or that defy the status quo.

As a scientist, I am not looking for confirmation bias; that would be intellectually lazy. However, I do not like the idea of bringing in quantum mechanics to explain how our brain works, simply because while we are making efforts to finesse models with explanatory power, the inclusion of quantum mechanics ideas is like adding mud to the football pitch - a Latin-American expression that sums up just how unhelpful something can be.

Obviously I feel terribly conservative saying that quantum mechanics does not yet have or may never have a place in the explanation of the brain’s mechanisms. Brain is psychology, biology, chemistry, physics, no doubt, but what I truly believe, and my reading of this book corroborates, is that the inclusion of quantum mechanics at this stage of our understanding of cognition and consciousness only adds confusion. To be fair, Werner Loewenstein does a great job of offering the reader a scientifically clear and understandable explanation of quantum mechanics. He provides a solid historical perspective on its relevance to both biology and physics, although neuroscience is much less mentioned and not really referenced.

And despite the fact that I enjoyed reading much of this engaging and witty book, I regret to say that I ultimately found it to be rather plagued by those witty metaphors. I must also point to two other things that made me uncomfortable: the use of the word “demons” to refer to biological entities (a concept largely dropped in the 18th century) and the anthropomorphisation of biological concepts, specifically evolution, which here is embodied with intentions and emotions. And to go three for two - although it might not be possible to kill three birds with one stone - I have to take issue with Loewenstein’s systematic use of the word “consciousness” in chapters where the topic is either a brain process and how to explain it with the use of quantum mechanics, or a cognitive process suffering the same fate.

Finally, however, Loewenstein arrives at coherence - not because he starts to sound lucid but because he lets this concept from quantum mechanics take over. And rightly so, since coherence is a powerful idea that seems to be gathering support in the study of biological systems at microscopic but yet supratomic level; that is, that light can be captured by a process employing quantum coherence to harvest energy extremely efficiently. In plants, this is called photosynthesis. In animals, Loewenstein says, the photopigments in the retinal layer use quantum coherence as the only way to capture one photon and cascade that fact as neuronal information. He then goes on to speculate that quantum mechanics actually plays at the level of brain tissue and brain networks, which is a much harder claim to support experimentally, and it makes Schrödinger’s cat uncomfortable. It certainly made me close the book with uneasiness.

If I were you, I would buy this book to experience all those feelings and more. Unless, of course, you prefer to read only things you are in agreement with, in which case I would buy another book.