Darwin’s Conjecture - Generalising Darwinism


Jason Collins


July 18, 2013

Over the last couple of months I have been a silent participant in Geoffrey Hodgson and Thorbjørn Knudsen’s reading group for their book Darwin’s Conjecture: The Search for General Principles of Social and Economic Evolution. After finishing the book and following the reading group discussions, I’m not sure I am in a position yet to offer a strong review or critique. But in the meantime, here are some notes about the book.

Hodgson and Knudsen advocate that Darwinism should become the unified evolutionary framework for the social and behavioural sciences. They consider that this has benefits that include establishing the role of variety in the evolution of complex population systems, which economists often aggregate or assume away. It also provides a way of bringing the observed suboptimality prevalent in the natural world into the social context.

To achieve this, they seek to formalise the application of the Darwinian principles. This is the most important contribution of the book. Much of the research on cultural evolution feels, for want of a better word, slippery. When I read works on cultural evolution I often find myself asking what is being replicated? How is it being transmitted? How is it being selected? Is it different from contagion? This is particularly the case where group selection enters the picture. Hodgson and Knudsen tackle these questions by seeking to define what exactly is being replicated and transmitted and accordingly, what is the replicator (the cultural equivalent of the gene) and what is the interactor (the organism or object that natural selection acts upon).

For some chapters, this approach is  useful. The chapter on whether social evolution is Lamarckian (modifications acquired during a lifetime are passed to offspring) is excellent. To assess this claim you need to understand the nature of transmission, which in turn requires definition of the replicator. When and how does the replicator change? Even though I didn’t agree fully agree with their conclusions, their approach allowed a clear assessment of what they were arguing.

Tying down these definitions is not a riskless enterprise, as social evolution does not have a relatively clear entity in “the gene” to select as a replicator. At an individual level, they argue that habits are the appropriate replicator. They prefer habits over memes as they consider it possible to give habits a substrate of biologically inherited instincts, whereas memes are based on habits and instincts and cannot be sustained without them. But why dismiss memes on this basis when they can be given the substrate of habits and instincts (or even a state of the brain) in the same way habits are grounded in biologically inherited instincts? Memes were also attacked on the basis of looseness of terminology, but given the book was designed around formalised Darwinism, why not tighten it? In some respects, I felt as though their discussion on memes was a battle in a long war that I do not know enough about.

Where the authors really started to lose me was when they moved into higher levels of evolution. As is typical when assessing multilevel selection, they noted the Price equation and how it can be used to partition selection at various levels of organisation. But when they laid out their proposed six levels of replicators (genetic, individual, organisational, symbolic, legal, and scientific and technological) across four levels of interactors (individual, organisational, national, scientific and technological organisations), a lot of the crispness of terminology seemed to disappear, along with tools such as the Price equation. The sharpness they brought to the initial chapters of the book faded.

There were a few nice lines in the book.  In dismissing arguments that human intentionality renders analysis of social evolution irrelevant, the authors note that intentionality itself has evolved from similar but less developed attributes among pre-human ancestors. Similarly with artificial selection, it is evolved humans doing the selection

On the flipside, there was also the occasional argument that grated me the wrong way, such as their suggestion that the impulse to produce and acquire in all human societies is a cultural propensity. This is pushing the cultural explanations too far.

Ultimately, the test of their work will be in the application. Although I enjoyed the attempt to tighten the use of some concepts that are often loosely used, it is only when we gain new insights from these tools that the effort will be proved worthwhile. As to whether that is likely to occur, I am not yet convinced (I still have some Steven Pinker like tendencies in this area). I am also reluctant to get sucked into some of the issues in the book as, to my untrained eye, they often appear semantic (as does much of the conversation in the reading group). That is another area where some real-world application will help, with some practical examples to render the material more real.

And as a last word, if you are interested in finding a book as a starting point on cultural evolution, this probably isn’t it. If you have already read a few books in the area, it is worth the effort.