Dennett is a philosopher by profession, who has only dabbled in evolutionary biology and cognitive science. Nonetheless, he has written the most complete and far-reaching book on cultural evolution since Joseph Heinrich’s “The Secret of Our Success”. Dennett carries on the mantle of Richard Dawkins’ theory of memes and pushes it further, but first he looks at the evolutionary origins of humanity and specifically our brains. Mutations in DNA almost never happen, it is a one in a billion type event, and still mutations are the backbone of all evolution. Furthermore, it is only the still-rarer “positive” mutations that will eventually survive and replicate. “In every generation, in every lineage, only some competitors manage to reproduce, and each descendent in the next generation is either just lucky or lucky-to-be-gifted in some way. The latter group was selected (for cause, you might say, but better would be for a reason). This process accounts for the accumulation of function by a process that blindly tracks reasons, creating things that have purposes but don’t need to know them.” This means that, though reasons exist, there are not necessarily corresponding “reasoners” or as Dennett puts it, in nature there most often is “competence without comprehension.” There maybe reasons for a behavior, but that does not mean that the organism doing the behaving is itself aware of those reasons- the reasons are free floating. Natural selection only requires “(i) variation in the characteristics of members of the population, (ii) which causes different rates of reproduction, and (iii) which is heritable.” Dennett continues with the evolution of the brain specifically. He stresses that unlike computers, to which they are often compared, brains are analog, brains are parallel (they execute millions of “computations” simultaneously), brains are carbon-based, but, most importantly, brains are alive (and therefore are subject to the laws of natural selection). A brain is “made of cells that are themselves autonomous little agents with agendas, chief of which is staying alive, which spawns further goals, such as finding work and finding allies.” Neurons are helped in this by their own plasticity, although they are specific, they are also mutable. Finally, Dennett is ready to explore memes, which are “culturally transmitted items that evolve by differential replication- that is, by natural selection” but are “transmitted perceptually, not genetically”. Foremost among all memes are words. They are the building blocks of all human culture. “Words are autonomous in some regards; they can migrate from language to language and occur in many different roles, public and private. A word, like a virus, is a minimal kind of agent: it wants to get itself said…. An informational thing doesn’t have a mind, of course, any more than a virus does, but, like a virus, it is designed (by evolution, mainly) to provoke and enhance its own replication, and every token it generates is one of its offspring…. Words are affordances that our brains are designed (by evolutionary processes) to pick up.” Importantly, while some of this is happening at the conscious level, a lot is happening imperceptibly and through no one’s design. “As a general rule of thumb, any artifact found in abundance and showing signs of use is a good whatever-it-is; following this rule, you can tell the good ones from the not so good ones without knowing exactly why the good ones are good.” Why are words so successful? “The capacity of language to direct attention to nonpresent things and circumstances is a huge enhancement.” It is what has separated humans from all other known living creatures. As David McFarland has argued, “communication is the only behavior that requires an organism to self-monitor its own control system.” Dennett also begins to tackle the idea of the “self” and the idea of consciousness. “Our access to our own thinking, and especially to the causation and dynamics of subpersonal parts, is really no better than our access to our digestive processes; we have to rely on the rather narrow and heavily edited channel that responds to incessant curiosity with user-friendly deliverances, only one step closer to the real me than the access to the real me that is enjoyed by my family and friends.” Rather than describing the state of consciousness as firmly black or white, Dennett proposes it is more shaded, while admitting, at this stage in neurobiology, it is very hard to know for sure. “We won’t have a complete science of consciousness until we can align our manifest-image identifications of mental states by their contents with scientific-image identifications of the subpersonal information structures and events that are causally responsible for generating the details of the user-illusion we take ourselves to operate in.” Culture, however, is beyond the realm of any one individual. It is the accumulated knowledge of the species at large. “The idea of distributed comprehension- the idea that we as a group might understand something that none of us individually could fully understand” is what human civilization rests upon. He quotes Alfred North Whitehead, “civilization advances by extending the number of important operations we can perform without thinking about them.” It actually advances as we create further competences without comprehension. It advances with the division of knowledge and the division of labor. “This distribution of partial comprehension is not optional. The edifices of social construction that shape our lives in so many regards depend on our myopic confidence that their structure is sound and needs no attention from us.” This is a sprawling book and any summation can hardly do it justice. Much of its joy is in its many detours and asides. Dennett concludes be reminding us, “there is not just coevolution between memes and genes; there is codependence between our minds’ top-down reasoning abilities and the bottom-up uncomprehending talents of our animal brains.”
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