Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Water has emergent properties?

  1. Sep 28, 2013 #1
    What do physicists think about water as an example of something with emergent properties?
    I wonder if the concept of emergent properties has become main stream in modern physics. If so, what happened to reductionism?
    Does this go for water?
     
  2. jcsd
  3. Sep 28, 2013 #2

    Pythagorean

    User Avatar
    Gold Member

    I don't see emergence and reductionism as being mutually exclusive. The emergent properties of water won't occur with one water molecule (or even a couple, really). But we can still explain the emergent properties in reductionist terms (coupling effects between the members of the ensemble). I don't know of any way of predicting all the properties of unknown molecules made by combining known atoms. Certainly we can make educated guesses, but material scientists use a lot of trial and error in the end.

    In modeling nature, there exists mathematical systems that are sensitive to initial conditions and aren't analytically solvable (thus requiring computers to solve numerically) and are fundamentally unpredictable despite being deterministic. Coupling several such elements together leads to new behaviors that there is no way (that I know of) of predicting.
     
  4. Sep 28, 2013 #3

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    No emergent property can arise that are not in accordance with the laws of interaction governing the "small".

    For example, independent measurability of momentum and position of a "particle" is a statistical assemblage effect that can be regarded as an emergent property of matter.
     
  5. Sep 28, 2013 #4
    Pythagorean and Arildno, thank you for your response. Do you use terms like 'emergence' and 'emergent property' in rigidly accurate sense as described in the wiki quote in the OP?

    Pythagorean you state that you don't see emergence and reductionism as being mutually exclusive, but the wiki definition of emergence, as I understand it, excludes deduction from the parts.

    Arildno, you state that no emergent property can arise that is not in accordance with the laws of interaction, but do you mean that these emergent properties are nevertheless not deducible from these laws?

    To be clear, do you believe in so called emergent properties of water, that are in principle not deducible from the most complete knowledge of a lower level?
     
  6. Sep 28, 2013 #5

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Hmm..I wrote "in accordance with", didn't I?

    That's something quite different from "deducible".

    Or what do you think?
     
  7. Oct 1, 2013 #6
    Arildno,
    Do you mean by 'in accordance with the laws of interaction governing the "small"' : 'within the broad boundaries of the laws of interaction, which are leaving a huge bandwidth for the 'not-so-small' to 'create ex nihilo' irreducible properties?
    Or are these laws strict and causing clear predictable effects, so there is no emergent property in the sense of not being deducible in principle from the most complete knowledge of a lower level?
     
  8. Oct 1, 2013 #7

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2016 Award

    Boy, you must have missed Phil Anderson's "More Is Different" essay, and all those papers by Bob Laughlin!

    You may also want to read this:

    https://www.physicsforums.com/showpost.php?p=2207270&postcount=81

    Zz.
     
    Last edited: Oct 1, 2013
  9. Oct 1, 2013 #8

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    "within the broad boundaries of the laws of interaction, which are leaving a huge bandwidth for emergent properties to come up (ex nihilo with something irreducible?)"

    That is PRECISELY what I mean.

    I don't understand what I've placed within a parenthesis; I must say that I cannot regard "deducibility" as a precise enough concept to be of any use. What is deducible for one person isn't deducible for another. And, we do not have any sort of solid knowledge to properly define "maximal deducibility" for humans in general.

    For example:
    Suppose the laws of the "small" allows a RANGE of behaviour for all matter to act according to.
    The behaviour of "The large" must necessarily be in accordance with that specified range, even though, obviously, the actual range of behaviour for "The Large" will show surprising statistical deviancies in what is "common behaviour" on that level, relative to what is "common behaviour" on the scale of "The Small". Such surprising statistical deviancies, for example that for "The Large", it is meaningful and possible, to measure position and momentum of a "particle" independently (and accurately) of each other, is one such "emergent" property.
    In my view, that is.

    (Note that Heisenberg's famed uncertainty relation is, in principle, as valid for "The Small" as it is for "The Large"; in the latter case, it shows that certainty is, indeed, a feature of the macroworld)
     
    Last edited: Oct 1, 2013
  10. Oct 1, 2013 #9

    Pythagorean

    User Avatar
    Gold Member

    Emergence is an ill-defined concept so different fields have slightly different definitions; my assumption, without looking at the wiki page, is that it's from pure philosophy perspective. I come from the nonlinear sciences perspective in which we already classify properties as emergent. This doesn't mean that the properties can't be explained in terms of reductionism, but it's not always automatically apparent how the reduced interactions give way to the emergent properties, so it can't be predicted from the reduced "particle interactions" but once you've seen the phenomena you can start trouble-shooting it and seeing how the reduced particle interactions affect emergent outcomes.

    Typical properties of emergent phenomena are degeneracy and distributed function, which further complicate said trouble shooting. Degenerate means several different kinds of interactions can lead to the same emergent phenomena and distributed means one reduced interaction may play a part in several different emergent properties. This makes troubleshooting hard. For instance, in biology, if you knock out a gene, other systems may compensate for it, so the effects you're seeing you can't directly contribute to lack of the gene as much as compensation by other protein networks. There's still a reductionist explanation, it's just obscured by the complexity of the system.

    I would also agree with arildno that deducibility isn't really relevant.
     
    Last edited: Oct 1, 2013
  11. Oct 1, 2013 #10

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    I'd say that "emergent" property would, for example, include a statistical deviancy in behaviour of a subsystem relative to statistical behaviour of the whole system.

    But, it doesn't follow that that subsystem's deviant behaviour isn't in accordance with the principles governing the WHOLE system.

    I would also emphasize ZapperZ's excellent reference.
     
  12. Oct 1, 2013 #11
    Pythagorean,
    I would prefer not go there. I want to keep it 'simple': H2O, does it posses 'emergent' properties or not?. I take it from your answer that you don't believe in emergent properties [edit: with regard to water] of the irreducible kind.

    ZapperZ,
    My question isn't about complex physical systems. My question is about water. Boy, you must have missed the OP.
     
    Last edited: Oct 1, 2013
  13. Oct 1, 2013 #12

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2016 Award

    I didn't! You asked this!

    That's what I was responding to. Or are you saying that you're asking if emergent properties IN WATER has become mainstream in modern physics? This would be odd and highly restrictive, because, after all, why would "modern physics" worry that much about this very narrow application of water?

    You asked a very broad question on emergent properties. I gave you not only a response, but also a direct, clear link.

    You're welcome.

    Zz.
     
  14. Oct 1, 2013 #13
    ZapperZ,
    No, I asked this (you quoted correctly the first time):
    Let me rephrase my question: What do physicists think about water as an example of something with emergent properties? I wonder if the concept of water as an example of something with emergent properties, has become main stream in modern physics. If so, what happened to reductionism?
     
  15. Oct 1, 2013 #14

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    I'm sorry. But you continually use two WORDS "emergent" and "deducible", both of which can be given a number of meanings.
    I'm sure that's not your intention, but that's hpw I read your posts.

    For example:
    Suppose the laws of interactions implies that a particular configuration of the small requires at LEAST 5 "particles".

    Then, for 5-particle systems and beyond, THAT configuration may appear, but NEVER for particle systems of less than 5 particles.
    Is that configuration an emergent property? I think it is.
    Is it in accordance with the laws od interaction? Most definitely!

    Is it LIKELY that a mathematician might be able to compute himself into all 5-particle configurations and be able to identify that particular configuration from his armchair? Not necessarily likely at all!
     
    Last edited: Oct 1, 2013
  16. Oct 1, 2013 #15

    atyy

    User Avatar
    Science Advisor

    Your question is ill-defined because it says "Emergentism. A property of a system is said to be emergent if it is more than the sum of the properties of the system’s parts." You need to clarify

    (1) whether you mean a water molecule or a mole of water
    (2) what you mean by parts
    (3) what you mean by sum
     
  17. Oct 1, 2013 #16

    AlephZero

    User Avatar
    Science Advisor
    Homework Helper

    My take on this is philosophically utilitarian, but it seems consistent with Anderson et al:

    "Emergent" is no more or less than the fact that understanding a system "in the large" needs different conceptual tools than understanding it "in the small".

    Of course as an engineer, I'm quite familiar with the joke about the physicist who tried to design some kitchen shelves by considering the behavior of the subatomic particles in the planks of wood. But that's exactly the point: classical continuum mechanics (described by tensor fields of stress, strain etc) is iIMO an emergent property of quantum field theory, and an engineer's "strength of materials" approach to designing cantilever beams is an emergent property of classical continuum mechanics. A mechanical engineer who designs a kitchen shelf by modeling the wood as a 3-dimensional anisotropic composite material is as big a fool as the apocryphal physicist.

    The fact that historically the three models of the shelf were discovered in the reverse order is beside the point.

    But I don't have any view on how that applies to the specific case of water. Sorry, water isn't my specialist subject
     
    Last edited: Oct 1, 2013
  18. Oct 1, 2013 #17

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    "needs different conceptual tools "

    "Needs" is a very strong word, AlephZero!
    I'll stretch myself into "convenience", but "necessity"?
     
  19. Oct 1, 2013 #18
    Arildno,

    My synonyms for the word 'deducible' are 'explainable' and 'understandable'. For instance the sentence 'some physicists hold the position that water has so-called emergent properties, which are in principle not explainable (or understandable or deducible) from the most complete knowledge of a lower level.'

    Atyy,

    Was it your intent to quote me? You didn't.
     
  20. Oct 1, 2013 #19

    AlephZero

    User Avatar
    Science Advisor
    Homework Helper

    Agreed, and that's the point, IMO.

    Try understanding the behaviour of a chaotic dynamical system without using tools like Poincare maps or Lyapunov exponents, and see how far you get....

    And I would call the Feigenbaum constant an emergent property.
     
  21. Oct 1, 2013 #20

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Isn't it, rather, constraints placed by reality upon such issues like computation time, rather than any LOGICAL need present here?

    This is veering off into philosophy..
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Water has emergent properties?
  1. Property of water (Replies: 3)

  2. Water property (Replies: 1)

Loading...