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The Origin of Life and the Hidden Role of Quantum Criticality
KentuckyFC writes One of the great puzzles of biology is how the molecular machinery of life is so finely coordinated. Even the simplest cells are complex three dimensional biochemical factories in which a dazzling array of machines pump, push, copy, and compute in a dance of extraordinarily detailed complexity. Indeed, it is hard to imagine how the ordinary processes of electron transport allow this complexity to emerge given the losses that arise in much simpler circuits. Now a group of researchers led by Stuart Kauffmann have discovered that the electronic properties of biomolecules are entirely different to those of ordinary conductors. It turns out that most biomolecules exist in an exotic state called quantum criticality that sits on the knife edge between conduction and insulation. In other words, biomolecules belong to an entirely new class of conductor that is not bound by the ordinary rules of electron transport. Of course, organic molecules can be ordinary conductors or insulators and the team have found a few biomolecules that fall into these categories. But evolution seems to have mainly selected biomolecules that are quantum critical, implying that that this property must confer some evolutionary advantage. Exactly what this could be isn't yet clear but it must play an important role in the machinery of life and its origin.
I did my Ph.D. in physical chemistry, focusing on electron transport in DNA, proteins, and other organic molecules. I read the arxiv paper and found it almost incomprehensible from this perspective. There is no reference to existing models of electron transport in biological systems(*), and it's not clear that their "generalized fractal dimension" for a protein has anything at all to do with electron transport. While it's possible that this approach is just so revolutionary that it doesn't need to be grounded in what's already known/believed about this field, it's more likely that this is just pseudoscience. Further supporting this hypothesis is the existence of phrases like "Why life persists at the edge of chaos is a question at the very heart of evolution" in the text. Serious science doesn't need that kind of hype in the paper.
*except at the end where they reference a couple experimental papers that tangentially relate to this topic
While these biological phenomenon may appear difficult for some people to comprehend, they aren't really all that complex at all.
Really? So you can predict how proteins fold? Which drug candidates will interact with which proteins and what effects they will have? How about just modeling the interaction of a protein and water? These all fall under NP-complete, which is a pretty much the epitome of complexity.
The OP is not 100% wrong, but as others have pointed complexity is not just subjective. There are systems with greater complexity than others, regardless of the beholder.
It's a mistake to say that, because someone has eyes which can be forced to focus on a distant object, those who can't see it are on a lower rank. This is exactly what leads us to marginalize some people who are deaf, or color blind, or too tall etc.
Furthermore, sometimes complexity signals a field not well understood. Someone, somewhere, somehow will come up with an elegant and simple view which will render the previous complex one useless (like e.g., the heliocentric view versus the geocentric). IOW simple is harder and comes from more powerful minds.
My apologies: I used the CS definition when referring to Parent's using computer programming as an analogy: "This is true for your analogy as well". For the discussion about biology I just said quantifiable, but there are a bunch of different ways to approach complexity in biological systems, some rigourous, some not, and even Mr. Complexity and Self Organization Himself (Kauffman) would use different ones depending on the problem he is currently looking at. For quantum criticality, the one wikipedia gives for physical systems: "complexity is a measure of the probability of the state vector of the system" is a good start. For systems biology or genetics, an information theory approach would be better.
What is the step count cutoff on complexity? Please quantify that for me. If you can't give me a formula that works across the board (you, after all, are using CS in a discussion about biology), it's subjective.
The subjectivity is bound by a constant factor. That's why big O notation works in the first place.
As a former molecular biologist who happens to be in the middle of a course on the design/synthesis of biomolecular electronics (biological semiconductors, conductors, LEDs, solar etc.), I wonder if the solution isn't as simple as this:
Essentially all biomolecules are synthesized by enzymes. Most are acted upon by enzymes or have some enzymatic activity during their functional life. Quantum criticality could be a useful property to enhance binding and catalysis at enzyme clefts (or other active sites) by enhancing charge/electron transitions in/on a molecule. Criticality may allow transitions and thresholds to be sharper, snappier, more selective.
"Quantum criticality" is just a label we give to a group of mechanisms (and the structures that encourage them) based on some test. I might label the many things that scare my friend's neurotic but otherwise imposing German Shepard as "Fido-phobic". This category might even be scientifically interesting -- if pulling pranks or stealing from my friend were major scientific goals at this point in time. That doesn't mean that squeeze toys that groan, rubber cubes that bounce erratically, and electric toys that "awaken" at random or after a delay share a fundamental property. They simply have properties that have interesting effects toward a certain goal (keeping her dog from interfering in our hijinks)