Saturday, 11 June 2016

Universal Darwinism in a nutshell


Darwinism's domain has expanded dramatically over the last century, to cover culture, development and other fields. This has led many thinkers to wonder how far the Darwinism goes. Universal Darwinism proposes that it goes far. This page offers a brief introduction to the basic ideas involved.


First, some basics: evolutionary theory is based on population thinking. It considers the world as composed of a population, an environment, and operations that act on the population members. It assumes that part of the world can be broken down into a set of similar entities - a population. A finite set of simple operations can then be applied to these entities. Entities can come into existence, go out of existence, make copies of themselves and merge with other entities. They can self-modify, interact with one another and with their environment. They can be filtered and sorted. They can move around and can be moved around. Meta information associated with each operation explains where, when and under what circumstances it is to be applied. The operations are usually applied repeatedly over an extended period of time.


In practice sometimes it is important to consider more than one population. Where multiple populations of entities interact, models of coevolution and symbiosis can be applied. These consist of descriptions of the additional populations, together with more operations describing how the entities from different populations interact.

Simplified models

Many models are simplified and focus on a small set of these operations, often ignoring other ones completely. For example, they may assume that interactions take place randomly, that the population is of infinite in size, or that the environment is fixed. Sometimes the simplifications assist mathematical analysis, other times they make computer simulation easier. Darwinism is not a particular theory, rather it is a toolbox which can be used to construct theories. One thing that is out of bounds is "arbitrary" mutations. Unconstrained mutation predicts everything and is useless. Mutations must be constrained to be naturalistically plausible. Other operations are subject to similar constraints.

Expanded domain

Traditionally, the populations involved consist of living organisms with genes made out of nucleic acid. The organisms involved are usually of the same species. Universal Darwinism expands the domain of evolutionary theory to include a wide range of other types of populations. Often these are conventionally considered to be part of the environment. For example, in culture, populations of cars, books, buildings, coins and words can be considered. In neuroscience, populations can consist of nerve impulses, or axon branch tips. In geology, populations can consist of rocks, streams, mountains or islands. In physics, populations can consist of atoms, molecules, photons or observers.

Often the same kinds of operations that are conventionally associated with Darwinism can be applied in these new domains. Operations involving damage and disintegration clearly apply to a very wide range of entities. Also, many entities persist and can be copied. Copying is sometimes though of as being unique to living organisms, but it isn't so: copying is ubiquitous in nature. The essence of copying is that information in one place winds up in more than one place - and that happens whenever rocks crumble, whenever streams part and whenever starlight hits dust. High fidelity copying is also common. For instance, position is often copied with high precision when entities split.

As a result of these shared operations, many of the parts of evolutionary theory can be applied to gain insights into these other realms. In particular, the concepts of fitness, adaptation and optimality which are traditionally associated with evolutionary biology turn out to apply widely to many types of system.This is Universal Darwinism in a nutshell.

Is the approach useful?

How useful is evolutionary theory in these other domains? It varies. In the case of cultural evolution, the answer is obviously, very useful indeed. In other cases, it often depends partly on how much overlap there is between the operations involved and those found in classical Darwinism. One common issue is limited heredity. With both DNA and culture, high fidelity inheritance systems allow open ended evolution and the accumulation of adaptations. However, with many simple systems, heredity is limited. A rock might inherit its position, momentum, chemical composition and temperature from its parent rock, but there's a limit on the number of times a rock can split into smaller rocks. Additionally, there are ceilings on the information carrying capacity of some entities. The tip of a lightning strike might carry information about charge and position - and encoding position might require a considerable number of bits - but there's still a limit on the amount of information so encoded. Such "information ceilings" represent additional limitations. These limitations don't mean that many standard Darwinian methods are not useful - but they should lead to constrained expectations regarding the scale of any resulting adaptations.

Relevance of population thinking

Another issue is the relevance of population thinking in the first place. With DNA-based organisms, a population of discrete similar entities is often the product of evolution - since the entities involved share a common ancestor. Often they flock together and interact with each other more than with other parts of their environment. In some of the other cases covered by Universal Darwinism, how to divide the world into entities is not always so clear and obvious. Even if the entities involved don't form a natural kind, it can still be useful to divide the world up into pieces and consider how they interact - that is simply standard scientific reductionism. However, the more the world divides neatly into pieces, the easier it will be to apply evolutionary theory to it. Note that even if you can't divide some aspect of the world up into pieces, you can still sometimes gain something by treat it as a single persisting entity - and then applying coevolution models.

Competing theories

A theory is only as good as the best of its competition. How have the phenomena covered by universal Darwinism been treated by scientists historically? We will consider two alternative theoretical frameworks:

  • One competing theory is from physics, or more specifically thermodynamics and statistical mechanics. This is the maximum entropy production principle. Instead of considering fitness maximization, maximum entropy production deals instead with entropy maximization. Maximum entropy production covers similar domain to universal Darwinism and successfully reproduces many of its predictions. However there are differences in emphasis and approach. For example, evolutionary theory has done a lot of useful work on path dependence and genetic drift. It has also made more study of when waste arising from conflict results in deviations from optimality.

  • Another competitor for universal Darwinism is Niche Construction Theory. Like universal Darwinism this deals with heredity transmitted via the environment and selection acting on environmental components. Niche Construction Theory is usually presented as a bunch of add-on components for Darwinism, though. Universal Darwinism produces very similar results by using standard Darwinism with no more axioms or complexity. Instead it treats the environment as a bunch of other Darwinian populations and reuses models of how different populations interact. As such, it would seem to be favored by Occam's razor. If Universal Darwinism is adopted first on these grounds, it is not obvious that there is any further explanatory work for Niche Construction Theory to do.

Deepening as well as broadening

Many biologists have long hoped that we will discover alien life - to illuminate which aspects of biology are fundamental and which are historical accidents. Universal Darwinism provides a very similar kind of illumination. In addition to the broadening of the domain of Darwinism, the new examples of evolution stimulate deepenings, revisions and generalizations of evolutionary theory. For example, cultural evolution stimulates the incorporation of intelligent design and directed mutations into evolutionary theory. I haven't covered these sorts of deepenings in this post - mainly through shortage of space - but several such deepenings are conceptually associated with Universal Darwinism.

Darwinism: what's in a name?

Some debate whether the resulting evolutionary theories should be called "Darwinian". Sometimes certain operations - such as entity copying - are required for the term to be applicable. Other times certain operations - such as inheritance of acquired traits - are forbidden. The term is used here mostly as a way of paying homage to Darwin's pioneering work on organic and cultural evolution. The term Darwinism is commonly used, though it has some associated baggage. In the end this is a terminology issue - the science involved is more significant.

How revolutionary?

Another issue is how revolutionary Universal Darwinism is. On one hand, most evolutionary textbooks need to be completely rewritten to cover the new domains involved. On the other hand Universal Darwinism expands the domain of Darwinism at very little cost in terms of additional axioms or complexity. It is often no more complex and traditional Darwinism. From this perspective it is no revolution at all. Having said that, expansions of the domain of Darwinism often represent revolutions - in the fields which are being invaded. For example, Darwinism represents significant revolutions in anthropology, economics and physics. In biology, the field was significantly transformed after adopting Darwinism. It seems reasonable to expect a similar large impact in other fields.

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