"Memes," the suggestion that ideas and other bits of culture can act like parasites by spreading from mind to mind without regard to the invaded host is a particularly compelling idea. It has caught on with a lot of people outside of biological science, but biologists have been generally skeptical of it. The problem has been that theories of memes did not take the characteristics of the host into consideration, and we have a strong sense from biological data that the host of transmitted information probably has to have some control over the processing of the information that they receive and transmit. The notion that our obvious strong propensity for social imitation also allows memes to enter us almost without resistance, then control us to force us to spread them seems a bit much.Aunger has formulated the meme theory in a way that resolves these problems. He is very careful in his reasoning compared to other popular books on memes and cultural transmission. He shows why cultural transmission is important, pulling from some of the same fascinating data as cultural selectionism researchers such as Boyd and Richerson. Cultural transmission matters because culture doesn't track with environmental, ecological, or genetic patterns. He then makes the crucial distinction for a true meme theory. He distinguishes the idea of a replicator and a duplication mechanism, and builds a model of memes specifically as replicators.Cultural selection theory holds that culture plays a role in biological evolution, but doesn't neccessarily consider bits of culture tobe composed of self-copying replicators. The reason the distinction is important, Aunger makes clear, is that if they truly can be seen in that way, then they add an additional causal force for culture to take on a life of its own to transmit itself through us. This is the causal force that other meme authors have taken for granted, and Aunger makes it explicit and potentially testable.In building his model of memes, Aunger finds that the definition can and should be made more specific, as a kind of complex residing in the brain rather than an arbitrary collection of artifacts, behaviors, and ideas. This model of memes gets around the problem of beliefs not being truly arbitrary by making it at least possible to connect the acceptance of memes back to our evolved computational engines as described by evolutionary psychologists.This is a very rigorous and well-considered argument that finally takes real anthropological and biological data into consideration rather than simply making vague analogies of culture patterns to infection patterns of microbes, or providing a too-facile explanation for things we don't agree with (those guys were just infected by "religion memes," but we're immunized from that.")I think this book is a landmark in the literature of modelling the transmission of human culture, and if the empirical testing it suggests bears fruit, it may well change the way we view human belief in general and have significant implications to epistemology.On the downside, while this book is non-technical, it is academic in tone and is unlikely to have the same popular appeal as Brodie's dramatic "Virus of the Mind" or Susan Blackmore's very provocative "Meme Machine." On the other hand, it heralds a potential start for a real science of memetics, addressing the truly important questions (such as "do we have memes or do they have us ?") which those others books attempted to answer but assumed the answer from the start rather than framing the question in empirically testable terms and a more specific definition of a meme, potentially telling us how well memes act act as true replicators.