Ideas Are Not Replicators but Minds Are

An idea is not a replicator because it does not consist of coded self-assembly instructions. It may retain structure as it passes from one individual to another, but does not replicate it. The cultural replicator is not an idea but an associatively-structured network of them that together form an internal model of the world, or worldview. A worldview is a primitive, uncoded replicator, like the autocatalytic sets of polymers widely believed to be the earliest form of life. Primitive replicators generate self-similar structure, but because the process happens in a piecemeal manner, through bottom-up interactions rather than a top-down code, they replicate with low fidelity, and acquired characteristics are inherited. Just as polymers catalyze reactions that generate other polymers, the retrieval of an item from memory can in turn trigger other items, thus cross-linking memories, ideas, and concepts into an integrated conceptual structure. Worldviews evolve idea by idea, largely through social exchange. An idea participates in the evolution of culture by revealing certain aspects of the worldview that generated it, thereby affecting the worldviews of those exposed to it. If an idea influences seemingly unrelated fields this does not mean that separate cultural lineages are contaminating one another, because it is worldviews, not ideas, that are the basic unit of cultural evolution. Does culture evolve like biological lineages do? It is clear that cultural entities (such as ideas, habits, mannerisms, attitudes, and languages, as well as artifacts such as tools and art) evolve in the general sense of incremental change reflecting the constraints and affordances of an environment (Csanyi 1989; Cziko 1997; Gabora 1997; Hull 1988a; Lorenz 1971; Lumsden and Wilson 1981; Plotkin 1997; Popper 1963; Hofbauer and Sigmund 1988a). Ideally we could flesh out a theoretical framework for this process that unifies the psychological and social sciences as did the theory of evolution for the biological sciences. Accordingly, there have been attempts to develop formal mathematical (Boyd and Richerson 1985; Cavalli-Sforza and Feldman 1981; Schuster and Sigmund 1983) and computational (Gabora 1995; Spector and Luke 1996a, 1996b; Baldassarre 2001) models of cultural evolution. Evolutionary theory has been also applied in general terms to units of culture referred to as memes (Aunger 2000; Blackmore 1999, 2000; Dawkins 1976; Dennett 1995; Gabora 1996) as well as to the analysis of growth and change in economics (Borger and Sarin 1997; Borkar et al. 1998; Metcalfe 2001; Rivkin 2001; Saviotti and Mani 1995; Witt 1992), financial  2004 Kluwer Academic Publishers. Printed in the Netherlands. Biology and Philosophy 19: 127–143, 2004.