According to Pinker, group selection “adds nothing to conventional history” as an explanation of cultural change. Rather than arising from processes of random mutation and indifferent selection, he argues, cultural traits arise and spread as a result of the complex intentions and interactions of agents: “Conquerors, leaders, elites, visionaries, social entrepreneurs, and other innovators use their highly nonrandom brains to figure out tactics and institutions and norms and beliefs that are intelligently designed in response to a felt need”. Pinker insists that natural selection isn’t natural selection unless mutations are random: “unless the traits arose from multiple iterations of copying of random errors in a finite pool of replicators, the theory of natural selection adds nothing to ordinary cause and effect”. In short, the variability that natural selection acts upon must be randomly generated rather than deliberately generated – and, in that sense, intelligently designed.
As Pinker himself observes, however, nobody ‘owns’ the theory of natural selection. On our view, the process by which variable forms are intelligently generated and intelligently selected is not a theoretically banal alternative to natural selection, but rather a special variety of natural selection, in which the generation and selection of variability is accomplished via cognitive systems (themselves evolved). As we see it, the theoretical utility of the concept does not derive from the randomness of the variability (or from the indifference of the selective process), but rather from the efficiency of explanation it affords. In any case, deliberate alterations in artifact form are arguably just as “random” as genetic mutations – both are subject to a host of constraints within which new variants can occur.
While we agree with Pinker that the multifarious intentions of agents shape the emergence and spread of cultural traits, these are merely aspects of the proximate causation in cultural evolution and do not preclude the possibility of selection by consequences. Moreover, a comprehensive account of cultural evolution should really consider all of Tinbergen’s Four Whys. Consider the problem of explaining why the moving pistons in a car drive the main axle. A proximate explanation is that the pistons in an internal combustion engine deliver power to the car’s wheels via a series of mechanical devices such as a crankshaft and gearbox. (And of course these features were ‘designed’ that way.) An ultimate explanation is that vehicles equipped with this arrangement actually move and the design was selected for. But a more complete explanation must also consider developmental questions concerning the nature and sequencing of the car assembly process, such as how pistons, crankshafts, gearboxes, and axles come to be installed and connected up. And we also need to consider the constraints on design imposed by prior forms of motor vehicle construction, which are essentially questions about phylogeny.
If the ‘ultimate’ perspective adds explanatory power in the biological domain (it is more efficient to talk about how singing is a behaviour that was selected for in male songbirds because it served to attract females in the ancestral past, than to give a blow-by-blow account of the fates of every songbird in evolutionary history) then it should also add explanatory power in the cultural domain (if the design of a product involved thousands of iterations of generate-and-test then it is more efficient to talk about how a particular design feature is adapted to, say, a particular commercial environment, than to detail the fates of the myriad intermediate forms along the way). Perhaps the reason why Pinker finds it hard to recognize this is that intelligent design is commonly associated with supernatural theories of creation that have no place in science. If so, that impediment to understanding can surely be dismissed. To appreciate that designed creations evolve does not expose us to the charge of theistic creationism.