There are a plethora of definitions for the meme, with most being variations of Dawkins original notion of a unit (whatever that means) of cultural transmission, where culture may be defined as the total pattern of behavior (and its products) of a population of agents, embodied in thought, behavior, and artifacts, dependent upon the capacity for learning and transmitting knowledge to succeeding generations. None of extant definitions of a meme is sufficient to allow a meme to be clearly recognized, measured, or provide the basis for scientific research. And without the establishment of a scientific basis and the ability to explain, predict, and control phenomena, memetics will remain a functionally useless pseudo-science. A few of the many definitions extracted from the literature include:
A self-reproducing and propagating information structure analogous to a gene in biology.
A unit of cultural transmission (or a unit of imitation) that is a replicator that propagates
in the meme pool leaping from brain to brain via (in a broad sense) imitation; examples:
―tunes, ideas, catch-phrases, clothes fashions, ways of making pots or of building arches Ideas that program for their own re-transmission or propagation.
Actively contagious ideas or thoughts.
Shared elements of a culture learned through imitation from others – with culture being defined rather broadly to include ideas, behaviors, and physical objects.
An element of a culture that may be considered to be passed on by non-genetic means, especially imitation.
Information patterns infecting human minds.
While the internal meme is equivalent to the genotype, its expression in behavior (or the way it affects things in its environment) is its phenotype.
Any information that is copied from person to person or between books, computers, or other storage devices. Many mental contents are not memes because they are not acquired by imitation or copying, including perceptions, visual memories, and emotional feelings. Skills or knowledge acquired by ordinary learning are not memes.
A (cognitive) information-structure able to replicate using human hosts and to influence their behavior to promote replication.
Cultural information units that are the smallest elements that replicate themselves with reliability and fecundity.
A rule of behavior, encoded by functional neuronal groups or pathways. [Behavior is action, whether mental or physical. Ideas such as tying shoe-laces or opening a door represent rules of physical action, i.e., rules of patterned neural-muscular interaction. Concepts such as apple, seven, or causality, represent rules of mental action, or rules of cognition, i.e., rules of patterned neural-neural interaction. Hence, physical movement is governed by memes which represent rules of physical action and thought is governed by memes which represent rules of mental action].
Any kind, amount, and configuration of information in culture that shows both variation and coherent transmission.
A pattern of information (a state within a space of possible states)].
A unit of cultural information as it is represented in the brain.
An observable cultural phenomenon, such as a behavior, artifact or an objective piece of information, which is copied, imitated or learned, and thus may replicate within a cultural system. Objective information includes instructions, norms, rules, institutions and social practices provided they are observable.
A pattern of information, one that happens to have evolved a form which induces people to repeat that pattern.
A contagious information pattern that replicates by parasitically infecting human minds and altering their behavior, causing them to propagate the pattern. Individual slogans, catch-phrases, melodies, icons, inventions, and fashions are typical memes. An idea or information pattern is not a meme until it causes someone to replicate it, to repeat it to someone else. All transmitted knowledge is memetic.
The smallest idea that can copy itself while remaining self contained and intact – essentially sets of instructions that can be followed to produce behavior While Dawkins focused on the meme as a replicator, analogous to the gene, able to affect human evolution through the evolutionary algorithm of variation, replication, and differential fitness, for near-term practical applications the relevant key characteristics of the meme are that it consists of information which persists, propagates, and influences human behavior.