The most basic element in evolution, whether biological or cultural, is replication. There are two steps involved in replication: the preservation of the information that is copied, and the means by which it is transmitted. This chapter asks in what form cultural information might be preserved.

In evolution of any form, what evolves is essentially information. Genes are a means of preserving biological information, and the format that they use is DNA. We know where to look for the units of biological selection (within organisms) and we know what form that information takes (DNA). In culture, however, things are not yet so obvious, and this is a real stumbling block for many who first encounter the meme hypothesis. It is all very well to suggest that culture “evolves” via memes, just as biology does via genes, but where exactly are these memes to be found and – most fundamentally – what are they?

The second half of this book looks in detail at the problem of memes' location, but this chapter concentrates on the issue of memes' underlying basis. Just as the course of genetic evolution has been shaped by its ultimate reliance on DNA, so the course of cultural evolution must ultimately be dependent on the nature of the information that is being selected. There was a time when Mendel's gene hypothesis was undermined by the absence of any real understanding of how heredity worked.