Memes have many different meanings to people and are a complex subject, but in the simplest sense they can be thought of as ideas that are replicators.  The reality, however, is much deeper than that because, in essence, they embody much of the abstract, explicit, and implicit knowledge we possess.  They are, in fact, an emergent phenomenon of our reality that enables information to flow in ways that are partially analogous to the evolutionary process.  Memes have profound cultural implications and, depending on the type of meme, they can lead to the growth of knowledge or its inhibition.

Similar to genes, memes contain information that humans are essentially the hosts for.  Unlike genes, memes need to include their own replication mechanism to survive.   David Deutsch's conception of memes states that they exist in two different forms: a mental representation and a behavior.   A meme is therefore selected for its ability to cause behavior that gets it replicated into new hosts, and so forth.

Deutsch divides memes into two different categories, rational and anti-rational.  A rational meme relies on the recipient's critical thinking to cause it to be replicated, while an anti-rational meme relies on disabling the recipient's critical thinking to get it replicated.  A scientific theory with great explanatory power, like the theory of evolution, is an example of a rational meme, while a belief that all vaccinations are bad would be an example of an anti-rational meme.  Both are abstract mental representations and both cause behaviors that encourage their replication.  Evolution as a theory gets replicated because it explicitly explains so much, while the anti-vaccination meme gets replicated because it appeals to emotions such as fear and suspicion that override more rational explanations.  This dichotomy of rational and anti-rational memes has profound implications within the context of cultures and their evolution.

The evolution of culture is the central ingredient of our growth in knowledge and civilizational progress.  Much of human history has been characterized by slow progress where humans have existed in static cultures that were dominated by anti-rational memes and therefore changed very little.   We are currently in an unstable period where Western civilization is transitioning from static societies to more dynamic societies consisting of more and more rational memes.

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