 According to Dawkins, replicators have three basic properties—longevity, fecundity and copy-fidelity. Longevity means longevity of the gene type in the form of copies through descent (Dawkins 1982b: 84; Hull 1980), although the stability of gene tokens is included in the definition in The Selfish Gene (1976: 18). No gene as a physical body lasts all that long. In mitosis, a gene loses half of its substance at each replication. What endures, he says, is not the entity itself but the information incorporated in its structure. It is this information that is copied with such high fidelity. Mutations do occur, but at very low frequencies. Even so, in some organisms, mutation rates must be too high because mechanisms have evolved that search out and repair such errors. Therefore, the genotype is an informational notion; information is equivalent to Aristotelian form. The type is the form of the tokens, in Dawkins’ view.