The world we live in, which created us as well, is a special place. It is special because it is made up of an extraordinary variety of diff...
The world we live in, which created us as well, is a special place. It is special because it is made up of an extraordinary variety of different types of components with myriad properties. This feature of our world seems natural, but it is by no means a trivial consequence of the material system of the universe.
The universe is composed of only a few different types of fundamental building blocks, but it is also possible that there are even fewer types of fundamental elementary particles than we know today. Extrapolating our understanding of the universe, we might even conclude that the universe is composed of only one type of many building blocks.
But if we just remain within the limits of our current knowledge, we can still be amazed at the diversity of the simplicity of our world. Our world is not just a set of elementary particles existing independently of each other, nor even the simplest complex substance, a cloud of hydrogen atoms, but a cavalcade of many different material systems with many different properties.
Where do these different properties come from, and how are the seemingly infinite different material properties created in a universe consisting of only a few types of fundamental constituent elements?
The trivial origin of properties
New properties can arise in complex material systems by the interaction of the constituent elements to form a bound system, whereby the constituents lose their original properties and form a new material structure with entirely new properties.
In this case, the origins of the new properties of the newly formed material system are usually easily explained and understood, for obvious reasons. The interactions that give rise to such complex systems are usually already well known in terms of their characteristics and functioning, and the appearance of new properties is considered a natural consequence of this bounding process.
New properties appear in a trivial way, for example, when a water molecule forms - such as polarity or the V-form - that are not characteristic of its constituent elements. With the formation of the water molecule, the hydrogen and oxygen molecules lose their original properties, and a new structure, a stably bound molecule formed by the interactions that create the connections, with trivial, obvious, well understood and explainable new properties.
Most of the properties of material systems are trivially generated properties. However, material systems can often have new properties that cannot be explained trivially.
The origin of emergent properties
New properties can arise in composite material systems in such a way that the constituent elements interact with each other without losing their original properties, while creating a material system with new properties. In this case, it is more difficult to explain and understand the non-trivial reasons behind the origin of the new properties in the newly formed material system. Such properties resulting from this process are called emergence.
Emergent properties are characteristics of composite systems consisting of many elements, where the building blocks are related to each other, but do not form a tightly bound structure.
For example, the properties of a material system built of water molecules, water in the liquid state have properties that are not features to its constituent element, the water molecule, such as viscosity or surface tension. These properties are created in an emergent way. A composite system, liquid water formed from a multitude of loosely connected water molecules. The water molecules retain their original properties and create a system with emergent, non-trivial new properties.
In our world, wherever loosely complex, multi-element systems exist, emergent properties almost always, and therefore naturally, emerge.
Emergent properties are unique properties of matter, intrinsic to the diversity of our world, and fundamental components of the complexity of our universe. For example, we consider the highest manifestation of matter, the appearance of consciousness, to be an emergent property.
Where do emergent properties come from and how are they created?
Emergent properties typically emerge in complex, loosely interconnected, multi-element systems, where the elements that form the system retain their original properties, retain individuality and autonomy, but function in a community, together, by interacting with each other.
According to the current definition, emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors that emerge only when the parts interact in a wider whole.
Science currently uses this deductive, descriptive kind of definition to define emergence.
In scientific literature, the emergent property is also usually associated with the self-organization of the building elements. Although self-organization is a frequently occurring causally related factor in the appearance of an emergent property of a system, self-organization is not strictly necessary for the emergent property to appear.
Without self-organization, for example, rainbow or gas pressure appear as emergent properties. It also implies that emergent properties are not only characteristic of scientifically defined complex systems, i.e. systems with adaptability, it is sufficient if the system consists of an appropriate number of elements that are in some way related. The relation, however, can be completely passive. Sometimes it can be enough if the building elements creating the emergent property are located in the same part of space.
The current definitions of emergence attempt to define the phenomenon in a descriptive, deductive way, examining the whole system from above. However, we can only be able to properly understand the appearance of emergence if we can interpret the phenomenon from a bottom-up, inductive view of the system, starting from the autonomous, dynamic behavior of the building elements.
To understand the appearance of the emergent properties on an inductive basis, it should be sufficiently enough to take into account two features of the system of elements, which are fundamentally necessary for the emergent property to appear: that the elements retain their identity, and that the system is must be composed of many, someway connected elements. These two primer assumptions are the starting point for an inductive interpretation of the emergent properties.
To inductively understand the phenomenon, let us first examine the origin of gas pressure as an emergent property.
The gas, as a material system, is a chaotic, unorganized collection of countless, independently and freely moving and colliding particles. In such a system, there is always a well-defined pressing force, called pressure, acting on a surface (for example on the wall of a vessel containing the gas). Pressure, as a phenomenon, cannot be interpreted for a single gas particle, exists only for a sufficiently large number of particles that are associated in some way, as they occupy the same space volume, hence, it is an emergent property of the material system.
What physical process results in the appearance of pressure as a phenomenon? Given a sufficiently large number of gas particles, a statistically well-defined quantity of chaotically moving particles will move at a statistically well-defined average velocity, so a well-defined kinetic energy of the particles will be directed at any given time in a well-defined, but not unique direction. This kinetic energy, generated by the statistical randomness arising from the chaotic motion of the particles, exerts a well-defined force when it strikes a surface. This phenomenon, if it is classified suitably, is called pressure.
Pressure is a typical emergent property. The property arises from the basis that the constituent elements of a system composed of many elements when interact (collide) but function independently, some property of the constituent elements (in this case, their motion,) is falling in one direction (in this case, geometric direction) according to statistical randomness. At a given instant, the kinetic energy of the gas particles moving in statistically similar directions and colliding with a surface, is added together and exerts a well-defined force of constant magnitude under given conditions. The emergent property of pressure arises.
With the example of pressure, the emergent properties of temperature, viscosity and density can be interpreted in an equivalent way. These cases are typically characterized by the fact that some property of the constituent parts of the system, based on statistical randomness, takes on a similar value and in this sense falls in the same direction. In the case of temperature, the average kinetic energy of the particles, in the case of viscosity, the average binding force between particles, and in the case of density, the average number of particles per volume, take the same value and therefore fall in the same direction.
It is important to note that direction in the sense used here is not a geometric direction (although it can be), but refers to a characteristic property of the independently functioning structural elements that take on a similar value in a kind.
A similar inductive approach can be applied to the somewhat more complex emergent phenomenon of the appearance of a rainbow. The random but statistically uniform arrangement of raindrops makes mixed light from one direction bounce back in a well-defined way in slightly different directions according to their wavelength. The emergent phenomenon of the rainbow is due to the statistically random uniform distribution of raindrops, a unidirectional property expressed in the distribution in the given multi-particle system.
In each case, the emergent properties analyzed so far have been generated by the convergence of some property of the elements that build the multi-particle system, and derived from a random statistical distribution.
In a somewhat more complex way, but following the same principle, we can also interpret the surface tension of liquids, i.e. the emergent property of moisture.
Inside liquids, the particles that form the liquid are surrounded in all directions by other particles that constitute the liquid. This uniform arrangement ensures a uniform distribution of the cohesive forces acting between the particles. At the boundary of the liquid, however, the situation is different. At the surface where the fluid is in contact with another material system, the cohesive force between the fluid particles is no longer uniform in all directions. At the surface, a different amplitude of force is exerted from the interior of the fluid, which is interpreted as surface tension.
The surface tension is a more complex emergent phenomenon in the sense that it does not just appear from a statistical distribution, but is based on a specific arrangement of particles. A fluid with a sufficiently large, but not infinite number of particles creates a surface at the boundary of a finite amount of matter. The uniformly distributed force acting between the particles of the liquid inside the liquid is no longer uniformly distributed on the surface of the liquid, and a directional difference in the force between the inside and the outside of the liquid is created. At the surface, at the location of this special arrangement, and by this special arrangement, a cumulative force, the surface tension is formed, which is interpreted as an emergent property.
We could also interpret surface tension as an emergent property by finding a common feature in the characteristics of property of the independently functioning elements in a system of many elements, in this case an asymmetry-related cumulative force, which gives rise to the emergent property.
In loosely complex systems, in which emergent properties are typically manifested, interactions, feedback mechanisms, and self-organizing processes between the building blocks that influence the behavior of the elements may also appear. In this case, it is often this interaction between the constituent elements, a feedback loop gives rise to the emergent property.
This type of emergent behavior is the emergence of large-scale atmospheric phenomena such as hurricanes for example.
The gas particles that form the atmosphere move chaotically. This movement is essentially based on statistical randomness, with no particular direction. Density differences based on temperature differences cause vertical air motion and the resulting pressure differences cause horizontal air motion in different directions in the atmosphere. The formation of large-scale hurricanes, however, is driven by a more significant global effect, the Coriolis force, which is generated by the Earth's rotation. The Coriolis force is a weak force at the Earth's surface, significantly weaker than the kinetic energy of atmospheric particles. However, the Coriolis force is a force with a global effect, acting in a definite direction. When random temperature-based motion causes more particles to move in the same direction as the Coriolis force, or even more so, density differences based on temperature or pressure differences cause air to move in the direction of the Coriolis force, the motion is compounded by a locally weak but significantly strong on a larger scale Coriolis effect.
The gas particles that move together in this way first may have an insignificant size compared to the size of a large hurricane, but they move in a sufficiently specific direction. This initially small system of co-moving mass can be continuously amplified by the positive feedback created by the Coriolis force and density differences, which can lead to the characteristic shape, size and strength of a hurricane.
In the case of a hurricane, we can see that an external force causes a well-defined characteristic of the independently functioning elements in a system built up of many elements to fall in one direction, move in the same way, accumulate and organize themselves into a circular motion of increasing scale and strength. The phenomenon is well known and can be simulated by computer modeling to represent the emergent behavior of the atmosphere.
Another feedback-based phenomenon is the emergence of traffic jams on freeways due to the movement of cars in the same direction.
A typical reason for freeway traffic jams is that in steadily moving traffic, even a slight slowing of the speed of a car causes the driver of the car following the slowing car at an insufficient distance to slow down even more than the car in front of it due to inattention and reaction time delay, in order to avoid collision. The effect is the same for the following cars, with the enlarged result. Hence, an initially small slowdown can cause serious disruption or congestion in traffic.
The formation of traffic jams is caused by certain behaviors of participants acting independently but interacting when moving in the same direction of traffic, the reaction time of action and the delay in changing movement falling in one direction, and an accumulation of deceleration occurs. This phenomenon is a well-known emergent behavior of cars moving together, and can be well simulated by computer modeling.
A similar emergent behavior is a characteristic pattern of movement of animals that move in clusters.
Animals organizing into groups is a typical evolutionary behavior that provides a survival advantage. These animals instinctively seek proximity to each other and maintain an average species-specific distance between each other. As the group moves, members also tend to maintain a typical distance, while random or externally induced changes in direction and speed may occur at some members. Such changes in movement, if sufficiently large, may also cause neighboring members to change their movements in an attempt to maintain distance. Over time, according to the individual and species-specific response time, the number of group members changing their movements increases, while the group progresses the movement to synchronize again to similar direction and speed. The result of this process is the characteristic group movement pattern, specific to the given species.
This specific, direction-changing movement is an emergent property of the group. In a group with many members, the behavioral characteristic of animals acting independently but influencing each other by keeping a distance, while moving, a property of movement accumulates over time to a specific direction and organizes the group.
Finally in the examinations of the examples, the emergence of consciousness is certainly also an emergent property of the functioning of neurons, since supposedly a single neuron is not self-aware. Although we do not know the mechanism of the emergence of consciousness, if it is indeed an emergent property of the working neurons, its emergence, given the proposed inductive origin of emergent properties, may also be produced by the convergence and accumulation of some feature of the functioning of independently operating but interacting neurons.
The hypothesis of the emergence of consciousness based on resonance of neuronal activity corresponds well to the inductively described mechanism of emergent properties.
Now we can try to form an inductive definition in general of the appearance of emergent properties: if in a system with many elements a parameter (characteristic) of the independently functioning but related elements fall in one direction or change according to a mathematically describable pattern, then the effect of this specific property can accumulate in the system as a whole, and by this accumulation, a fundamentally new property appears as emergence in the system, which is, hence, specific only to the whole system.
By examining the behavior of the individual elements that create the system, it is usually difficult to deduce which properties will fall in one direction and accumulate at the level of the system as a whole. This is the reason why emergent properties are difficult to predict.
The classification of emergent properties
At the empirical level, emergent properties are usually classified deductively into two groups, distinguishing between weak and strong emergence.
Weak emergent properties are actually considered to be those properties that can be derived from the behavior of the elements that build up the system in a way that is well understandable. Weak emergent properties usually are not predictable for the reason mentioned above, but once a property has emerged, the origin of its emergence can be understood by examining the system’s building blocks.
Strong emergent properties are considered to be those properties whose appearance cannot be well explained or understood even with knowledge of the behavior of the building elements that form the system.
This distinction is confusingly subjective, as it is perceptibly based on the level of actual knowledge.
In a somewhat more objective way, but still apparently linked to actual knowledge, emergent properties can also be distinguished on the basis of practical simulatability. According to this definition: weak emergence is a type of emergence in which the emergent property is amenable to computer simulation or similar forms of after-the-fact analysis. If not, it is called strong emergence, which it is argued cannot be simulated or analyzed.
Although this definition seems to be a refinement of the first definition of the classification of emergent properties and not a different definition in principle, the generalization of simulatability seems to be a suitable way to classify emergent properties objectively, by their essence.
Following this generalization, the suggested definition is: the emergent property is weak if it can be generated in a fundamentally different material system, other than the original one, if it can be simulated. In addition, strong emergent property can only be created by emulation, i.e. the emergent property only appears in the original kind of material system, it cannot be created in a fundamentally different material system naturally by any way.
The essence of this proposed definition is the objective distinction that does not originate from the lack of actual knowledge, but based on the objective existence or impossibility of the simulatability.
However, even by using this definition, it is still an open scientific question whether a material property actually exists that can only be manifested in a particular material system, and any other material system is incapable of producing the property naturally. Does strong emergence actually exist according to this definition?
It is a scientific presumption that if an emergent property in a material system is a consequence of evolutionary processes, it might be possible that the emergent property cannot be simulated in another kind of material system. The emergent properties of complex systems, i.e. systems capable of adaptive behavior, such as the behavior of the stock market, also seem not to be reliably simulated, hence it is a strong emergence.
The following definition may therefore be suitable for the proposed objective classification of emergent properties, which is not based on our actual knowledge, but on the essence of emergence: if an emergent property can be simulated, can be created in a different material system, it is weak emergence. A strong emergent property can only be emulated, it can be created only in the original kind of material system.
This definition also raises a fundamental philosophical question. What is the consequence of the existence or non-existence of strong emergent properties in the universe according to how it was defined here? The emergent properties of evolutionary and complex systems are explicitly difficult to simulate, but the question is defining in nature. Does a strong emergent property exist or cannot exist regardless of our ever-existing knowledge?
Whatever the right answer to this question is, it has fundamental consequences for our world. If there is no strong emergent property in reality according to the proposed definition, then the entire universe can be simulated, even if not replicated, still can be created in other material systems.
And if indeed strong emergent properties exist, what are those, why can they exist in the universe, and what are the reasons for their existence?
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