ConclusionThis simple four stage model helps us to analyse the mechanics of meme replication, and the different requirements a meme must satisfy to spread successfully. It moreover helps us to situate and to systematize a more intuitively developed list of objective, subjective, intersubjective and meme-centered selection criteria. Although the four stage model suggests a formula for calculating memetic fitness, the theory is as yet insufficiently developed to unambiguously determine the parameters of the equation. However, the list of selection criteria does produce a range of qualitative predictions, which can be empirically tested.