13. Emergent Properties
Definitions
Property - the name given to the way an organization of matter interacts with its environment.
Consider, for example, the property of color. A leaf has the property greenness because its pigments selectively absorb all the colors of the incoming light save green. We say the proton has the property of positive electric charge because it repels other protons and attracts negatively charged electrons. A property then, as used here, is a description of an objects interaction with the world.
Emergent properties - those novel ways of acting that come into being with the increase in organizational complexity of systems. Emergent properties are constructions of a whole system and do not belong to the component parts of the system.
Emergent properties are collectives that disappear when the communicating relationship within the system is disrupted. Good examples are the properties of pressure and temperature of a gas.
Background
Progress is a value laden term. To say that the world progresses is to declare that change is taking place and that the direction of that change is agreeable to the person making the statement. Much of what is called progress is the emergence of new products, processes and properties that result from the increased complexity of the organization of materials. Often the aim of scientific endeavors is the production of new emergent properties. Technology is the result and it is the proverbial two-edged sword. But if the world progresses at all it is by means of emergent properties.
The point of view taken here is that humans emulate nature by combining simpler systems into more complex ones in the search for new properties.
Discussion
In the beginning there was only the primordial fireball. All was energy and disorganization. Expansion cooling allowed matter to condense and permitted the strong nuclear interaction to organize atomic nuclei. Then the force of gravity began its work. These forces along with the weak nuclear interaction and electromagnetism constitute the forces that fabricated our emergent universe.
All through the subsequent history of the universe derivative emergent properties have appeared as new systems formed.
As examples the following table lists some systems and some of the emergent properties associated with them.
| Self-Organizing System | Emergent property |
| The atomic elements | Chemical reactivity |
| Atomic and molecular aggregates | Weight, temperature, density, smell |
| Sugar carbohydrates | Sweetness |
| Orientation of polar molecules | Magnetism |
| Volume of gas molecules | Pressure, temperature |
| Transparent Body | Refraction |
| DNA | Self-replication |
| The biological cell | Life |
| Biochemical systems | Enzymatic catalysis |
| Chloroplasts | Photosynthesis |
| Many biological systems | Sexuality |
| All living organisms | Homeostatic actions, reproduction, assimilation and growth, response to stimuli |
| Some insect groups | Social interactions |
| Some animal groups | Flocking, schooling, herd formation |
| Nervous system | Sensation |
| Neural cell aggregate | Brain function |
| Brain | All subjective experience |
| Human population | Mortality patterns |
| Human social system | Cooperation among individuals |
Thresholds for emergent properties
Some properties emerge only when sufficient masses of matter are involved. For example, diffusion, convection and conduction of heat take place among large numbers of molecules. A large number of neurons must be linked for consciousness to emerge. For a human social system to show cooperative behavior there must be a minimum of two individuals.
The whole subject of necessary thresholds for emergence to take place is an area for future research.