Describes the phenomenon that certain properties appear in a group or system that were not (recognisably) inherent in its parts or components.
Groups or systems can, as a whole, show properties that are not apparent in their components. This “appearance” of new properties by combination of elements is called “emergence”.
This concept also extends to the disappearance of properties; for example, both sodium and chlorine are toxic, whereas this property no longer appears in this form in the compound – sodium chloride, i.e. common salt.
In a certain sense, this also applies to properties that are undefined or have no real meaning in singular items but are relevant in groups or combinations. For example, references to differences, can fall under this category, like the following:
Do the horses in this herd have multiple colours?
This questions (or any answer to it, except possibly mu ) makes limited sense for a herd of only one horse.
The principle of emergence limits the possibilities of making logical inferences from the components to the whole (fallacy of composition), as well as conversely from the whole to its components (fallacy of division).
This can also be understood as a limitation to the principle of “dictum de omni et nullo” (distributivity), since this implies that there are properties which are true for all members of a group, but not for a single member (like, in the above example: “multi-colouredness” of the horses in a herd).
The opposite of emergence is resultance, which describes properties of the whole that can be inferred from properties of the components.
The concept of emergence has proven extremely helpful in solving a wide range of logical problems. For example, many of the classical paradoxes can be resolved by considering the properties described as emergent.
An often-voiced criticism against the concept of emergence is the claim that it is based on incomplete knowledge about the components’ properties. With deeper knowledge, emergent properties would presumably become resultant (see also: Determinism).
Whether this is true in all cases is certainly worth some discussion. However, one should at least consider the possibility in individual cases and establish whether a strict definition of emergence would still apply with deeper knowledge, depending on the specific case at hand.