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I think 'emergent property' just means it's something that depends on the particular configuration of a set of elements that vanishes if you just look at the el

I think 'emergent property' just means it's something that depends on the particular configuration of a set of elements that vanishes if you just look at the elements in isolation. E.g. words are an emergent property of the elements of an alphabet. It is kind of hand-wavy and you often find the phrase 'holistic' in the same paragraph as 'emergent', which reflects that it's a kind of pushback against entirely reductive approaches, but it really just means that if you want to reconstruct a complex entity (like an automobile) you can't just count up the parts, at each stage of reduction you need to save this set of information describing the relationships between elements if you ever want to reconstruct the overall system from the most fundamental components. It's essentially just an abstraction, I think. The justification is that you can wrap up complexity into hierarchies of little black boxes that have predictable behavior. E.g. https://guava.physics.uiuc.edu/~nigel/courses/569/Essays_Spring2018/Files/gupta.pdf https://guava.physics.uiuc.edu/~nigel/courses/569/Essays_Spr... >"The idea of emergence in physics is pervasive especially in condensed matter and cold atom physics. For example, superconductivity and superfluidity are both described by a condensate, which is an emergent state of matter with finite fraction of particles in the ground state and long range order." The suggestion here (further developed in above paper) is that spacetime is also a kind of 'effective description' based on some other underlying microscopic organized structure, which is a theory that's likely hard to test.

nemo44x 4y ago
> just means it's something that depends on the particular configuration of a set of elements that vanishes if you just look at the elements in isolation Sort of like how all the parts of an engine, even when connected, do nothing if fuel isn’t being pumped through. We can not proclaim we have knowledge of the engine by simply understanding many of its parts but failing to grasp how fuel moves through it. And instead say when these parts are together motion “emerges” and believe we are profound.
- tsunagatta 4y ago
  Linear and highly predictable systems like automobile engines are not really comparable to chaotic systems like the weather or the universe: they demand separate modes of analysis. Emergent behavior is one of these lenses of analysis that is useful for chaotic systems, so it is natural that trying to make comparisons to an engine don’t really work with it. For a simple physical system that is chaotic, i.e. does display emergent behavior, good examples I’ve heard are things like triple pendulums, or the currents of water in a river.
- empyrrhicist 4y ago
  I mean, couldn't you absolutely say you know more about an engine than before by invoking emergence? A skilled mechanic ignorant of physics could measure fuel flow and heat produced under different conditions, and try to figure out how the pieces fit without ever understanding the Carnot cycle - it's a useful way to describe what we know, even when we know it's not a complete picture. We haven't stopped studying consciousness after having concluded that it's a phenomenon that emerges from brains and their neurochemical environment by studying the pieces. I feel like your critique is fundamentally misguided.
magicalhippo 4y ago
Here's an article[1] trying to define the term a bit more rigorously. Here we discuss a sharp definition of the narrow concept of emergence in physics; we give a mathematically precise meaning to the notion of ‘qualitative difference.’ We propose the following: An emergent behavior of a physical system is a qualitative property that can only occur in the limit that the number of microscopic constituents tends to infinity. Which is essentially the opposite of what you mention (vanishes when looking at the microscopic constituents). [1]: https://www.nature.com/articles/npjquantmats201624 https://www.nature.com/articles/npjquantmats201624
- photochemsyn 4y ago
  Interesting article. It mentions phase changes here: > "Critical phenomena represent another distinct form of emergent properties." A single water molecule won't undergo observable sharp phase changes from ice to water to steam as the temperature is increased, so the emergent property vanishes when looking at the (isolated) microscopic constituent.

nemo44x 4y ago

> just means it's something that depends on the particular configuration of a set of elements that vanishes if you just look at the elements in isolation Sort of like how all the parts of an engine, even when connected, do nothing if fuel isn’t being pumped through. We can not proclaim we have knowledge of the engine by simply understanding many of its parts but failing to grasp how fuel moves through it. And instead say when these parts are together motion “emerges” and believe we are profound.

tsunagatta 4y ago
Linear and highly predictable systems like automobile engines are not really comparable to chaotic systems like the weather or the universe: they demand separate modes of analysis. Emergent behavior is one of these lenses of analysis that is useful for chaotic systems, so it is natural that trying to make comparisons to an engine don’t really work with it. For a simple physical system that is chaotic, i.e. does display emergent behavior, good examples I’ve heard are things like triple pendulums, or the currents of water in a river.
empyrrhicist 4y ago
I mean, couldn't you absolutely say you know more about an engine than before by invoking emergence? A skilled mechanic ignorant of physics could measure fuel flow and heat produced under different conditions, and try to figure out how the pieces fit without ever understanding the Carnot cycle - it's a useful way to describe what we know, even when we know it's not a complete picture. We haven't stopped studying consciousness after having concluded that it's a phenomenon that emerges from brains and their neurochemical environment by studying the pieces. I feel like your critique is fundamentally misguided.

magicalhippo 4y ago

Here's an article[1] trying to define the term a bit more rigorously. Here we discuss a sharp definition of the narrow concept of emergence in physics; we give a mathematically precise meaning to the notion of ‘qualitative difference.’ We propose the following: An emergent behavior of a physical system is a qualitative property that can only occur in the limit that the number of microscopic constituents tends to infinity. Which is essentially the opposite of what you mention (vanishes when looking at the microscopic constituents). [1]: https://www.nature.com/articles/npjquantmats201624 https://www.nature.com/articles/npjquantmats201624

photochemsyn 4y ago
Interesting article. It mentions phase changes here: > "Critical phenomena represent another distinct form of emergent properties." A single water molecule won't undergo observable sharp phase changes from ice to water to steam as the temperature is increased, so the emergent property vanishes when looking at the (isolated) microscopic constituent.