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Can biological processes be explained using physical laws?

  1. Jun 20, 2015 #1
    Do we understand how the physical laws of the universe created biology?

    How can we explain cell division, consciousness, evolution, as a product of matter operating in a universe governed by laws?
  2. jcsd
  3. Jun 20, 2015 #2
    There is a general term for this called 'emergence'.
    Quite complex dynamic systems can and DO evolve from an intrinsically simple set of rules.

    It is not limited to biological systems, but those are a very good example, probably the best example.
  4. Jun 20, 2015 #3


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    According to all experiments done so far, all parts of life follow the same laws of physics. Biological systems (or even large molecules) are too complex to calculate their behavior from scratch with fundamental physics only, but there is no reason to expect a deviation. Effective models can describe those larger systems very well. Chemistry and biology are/have such models.

    What do you mean with "created biology"? If you refer to abiogenesis: there are still many open questions, but the gaps get smaller and smaller over time.
    A huge number of atoms, arranged in such a way that something happens that we call "cell division".
    Depends on the definition of consciousness.
    Even more atoms involved. Way too many to track them individually.
  5. Jun 20, 2015 #4
    It's pretty incredible really isn't it, to think that something as unimaginably complex as a human being can arise according to preset laws.

    It makes me think about emotions and awareness. What are these things? Are they just an illusion? It's mind boggling to think that these things are just the result of atoms assembling themselves together.
  6. Jun 20, 2015 #5
    Trillions of atoms in a very specific configuration which at a macroscopic level are configured that way because :that way: produced a self replicating system, (which we call life).
    The very first self replicators are unknown and would have been simple(ish) organisms of course, but since then, natural selection neatly explains how it is that ever more complex creatures developed.
  7. Jun 20, 2015 #6
    So there is nothing 'inherent' about things at all, if that makes sense.

    If I look over at my friend Fred, Fred doesn't actually exist at all. He is just the result of atoms assembled into a system that I interpret as my friend Fred.

    Deep stuff!
  8. Jun 20, 2015 #7
    Fred exists and Fred is an assemblage of atoms which has the characteristic you define as human.
    However Fred is not a random mix of atoms, he is a highly complex set of interacting systems, (as well as probably being a great guy to know)
  9. Jun 20, 2015 #8
    But when people think of concepts like a soul, or just that feeling that people are 'people', more than just a physical mass, that isn't true. That is a subjective interpretation and not 'truth'.
  10. Jun 20, 2015 #9
    The aim of science is discover plausible explanations for things which are observable and measurable, (and make testable predictions)
    Ideas like 'soul' and 'feeling' are not measurable/observable things and therefore science does not attempt to do so.
  11. Jun 20, 2015 #10
    Absolutely fascinating.
  12. Jun 27, 2015 #11
    Importantly here we don't know whether or not laws are "preset"* but that this context fades against the fact that evolution is contingent. If you started Earth all over again, you wouldn't get the same result, including us. [Lenski's long term experiment demonstrates that, for example.]

    * E.g. symmetries and symmetry breakings like causality (relativity) may be forced in order to have any physics at all, at least it is difficult to envision physics without them. But the set of symmetries and symmetry breakings that makes the standard model or particles may not be so constrained but was set by coincidence, at least one can envision particle models with differing masses.

    Emotions and awareness are demonstrated biological traits, evolved because they increased the fitness of the population at the time and potentially kept because they still do so, or don't do sufficient harm, or else are 'locked in' by contingency. I wouldn't worry too much about how they work, but enjoy them while I have them.

    The same can be said for evolution as for the area of abiogenesis, remaining questions will always be at hand. But lately we can say so much more on abiogenesis, because while there were proposed or seen problems, akin to the original chicken-and-egg problem of DNA and protein synthesis, they have all (which I know of) fallen in the last year. While we do not yet know all the details of the darwinian pathway of small, survivable steps life emerged along, something that is shared by all phylogenies, we do know that there are no stumbling blocks.

    For a similar example, bats are known to have complex echolocation when they use it to catch prey. They can modify the strength to resolve the prey as they come closer without drowning the return signal in a high volume return "scream". How did they evolve that, while not starving to death meanwhile? It now turns out that when you live at the equator, the insect prey is large enough (I think was the resolution) that you don't need the volume control that other bats have evolved in temperate zones. Darwinian chicken-and-egg problem resolved by more data.

    Coincidentally, the Astrobiology-15 conference has a session on testing pathways. It seems to attract science on the most likely pathway, the "fuel cell" theory. It emerged as a theory after studies of the cell, more precisely chemiosmosis, and what type of geosystem could realize it. A recent result claims further that there is a physical constraint so that chemiosmosis can only evolve in those geosystems. That is, even if cells emerged elsewhere, they have to evolve metabolic efficiency (need chemiosmosis) in those settings, a fact (besides others) that makes the settings the most likely emergence environment.

    But the upshot is, even if there is still no consensus on the theory of emergence, there is now predictive, well tested theories and observations, and astrobiology (the science of abiogenesis) is now, unless I am mistaken, so called "normal science".

    Re cell division, it is a basic property of membranes, you can see it when you blow bubbles. There is a recent paper that likely demonstrates, by some abiotic enzyme cycle building membrane components, that cell growth and division are purely physical processes at heart, so that early cells (which encapsulation in fuel cell theory starts out as passive and mineral like, as pores in chemical garden effluent encrustations) likely coopted what was at hand. [But I haven't read it yet.]
    Last edited: Jun 27, 2015
  13. Jun 27, 2015 #12


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    Yes but if you look at Fred as the sum total of all that made him come to be, you should also keep in mind that he's had 3.5 billion years of trial and error to assemble himself. :smile:
  14. Jun 27, 2015 #13


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    At present, we believe can "in principle" explain everything using the known laws of physics, except for consciousness (which we are not even sure how to define).

    But people are trying.

    Could we build a conscious robot?
    Owen Holland

    Last edited: Jun 27, 2015
  15. Jul 4, 2015 #14
    Re consciousness, there is a biologically motivated theory of it now, Graziano's. It solves both the weak (when conscious) and strong problem (how conscious), and I hear that it is the only one that does so. Seems initial testing has been passed, and if it has no rivals the problem is solved.

    The definition becomes "attention of attention", i.e. there is a locus in (at least) primate brains that monitors attention (the transfer of information from sensory parts to parts more related to motor functions) and a further one that monitors that or in other words is attentive of what we are attentive of. E.g. we know somewhat what we are attentive of. (And that is presumably why we have to make up stories of what we do up to 7 s after the brain has decided on an action. Else we would run up against the emotional problem that the story telling "attention of attention" part has no control whatsoever but "consciousness" is just along for the ride despite feeling in control.)
  16. Jul 10, 2015 #15
    This question confuses me. What would be the alternative?
  17. Jul 10, 2015 #16


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    Well, the alternative - by process of elimination - would be supernatural. But since that falls outside the scope of this forum, I would have thought that this entire thread should have looked more like this:

    Q: Can biological processes be explained using physical laws?
    A: Yes.
    Thread locked.
  18. Jul 10, 2015 #17


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    Agreed, the OP has been answered.
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