Darwin’s Theory of Evolution is primarily talked about with regards to Genetics, but in fact he intended it to be substrate neutral. He included passages in his book "The Descent of Man” to that effect, for example “The survival or preservation of certain favoured words in the struggle for existence is natural selection”. Darwinian principles have been applied successfully outside of genetics to a long list of fields, including Psychology, Economics, and Computer Science. Memetics is simply the application of Darwin’s theories to the evolution of human culture.
Only three characteristics are needed in a system for adaptive evolution to emerge. You need a population that’s capable of replication, variation in what’s copied, and selection pressure where only the fittest survive. In genetics the replicators are genes, which randomly mutate during cell division, with the genes conferring the most advantage to their hosts being more likely to survive, by being passed on through reproduction. In memetics the replicators are memes, which mutate through human creativity, with the memes conferring the most advantage to their hosts being more likely to survive, by being remembered and shared. When there are conditions of scarcity with competition for resources, what determines the winners and losers in evolution is Richard Dawkin’s trinity of replicator attributes: Fidelity, Fecundity, Longevity.
Fidelity is how faithfully the original is copied during replication. In the case of genes there are only small differences, but with memes they can be altered beyond recognition. If nothing of the original remains, it hasn’t really been replicated at all, yet if each copy is identical as with a document stored on your computer, there is no mechanism for it to evolve and adapt to the environment. Under conditions of uncertainty, random mutation is a robust strategy, guaranteed to eventually explore all options given enough time. Whereas if the best evolutionary paths can be inferred, intelligent design may confer an advantage. For example we can guess that starting a fire with a wet sponge wouldn’t work, so we don’t have to waste resources testing it on the way to inventing the match. Genetic mutation by contrast is extraordinarily wasteful, but can avoid missing non-obvious solutions.
Fecundity is the ability to produce offspring, a measure of fertility, or shareability. This is a function of both transmission – how easy is it for the replicator to be copied – and of assimilation – how easy is it for its contents to be encoded in the host. Viruses that we’ve already developed an immune response to, have diminished ability to spread. Memes that are consistent with our existing identity, are more likely to be accepted and incorporated by us. This is a feature of the replicator itself, but also contextual to the environment in which they are copied. When conditions shift, it can lead to mass extinction events and opportunities to fill new ecological niches. Finally longevity is important: more time gives more opportunities to replicate. For example viruses that can avoid the immune system for longer, have more chances of spreading by infecting others. Memes that are memorable, are more likely to be top of mind when there is an opportunity to share, but also stick around for more such opportunities.
Wherever there is replication, variation, and selection, evolution will emerge, and only the fittest will survive. There’s no moral, or subjective consideration here: fittest doesn’t mean “best”, “strongest”, or “most desirable”, it simply means “best suited to the environment”. We developed intelligence because that’s what helped us survive, but many plants and animals thrive with far simpler decision-making. If our environment shifted to no longer reward intelligence, something so resource intensive would quickly (on evolutionary timescales) fade away.