They have come a long way, those replicators. Now they go by the name of genes, and we are their survival machines.
He's calling them replicators because anything that survives and replicates can form a building block of a unit that can be completely different to our believed perceptions. Read Chapter 11 'Meme' (he's actually coined this term in 1976) and has written a brilliant chapter on Meme and explains how memes are building blocks of something different to a DNA but, in any case, have a lot of similarities to it.
