Wednesday, 31 August 2011

Natural production and natural elimination

There's a chapter about "Generalised Darwinism" in my Memetics book. Here's a promotional video about one topic within that area:


Hi, I'm Tim Tyler - and this is a video about natural production and natural elimination. This pair of concepts represents an alternative to selection and drift when it comes to visualising and modelling the process of evolution. They are extremely basic concepts which arise naturally when attempting to generalise the Darwinian framework.

An understanding that culture evolves along Darwinian lines has led many of those involved to wonder what other systems exhibit Darwinian dynamics.

It has also prompted a revisiting of the foundations of evolutionary theory. I have a whole chapter about Generalising Darwinism in my new memetics book. Here I will describe some of the more significant results.

Natural selection beyond biology

Most people are familiar with the idea of natural selection. However, many people associate the idea with life - and with living systems. In fact natural selection represents the action of a more general principle that also applies systems which are not alive.

The truth of this has long been appreciated. For example, here is Richard Dawkins, writing on page 12 of The Selfish Gene:

Darwin's survival of the fittest is really a specific case of a more general law of survival of the stable. The universe is populated by stable things.
In fact, the familiar process of natural selection is not confined to biology. It affects everything that comes into existence. Whether or not it comes into existence via a copying process is irrelevant. Some abiotic examples of the effects of natural selection include:
  • Pebbles tend to be made of hard materials;
  • Islands tend to include hard rocky outcrops;
  • Planets tend to have circular orbits.

New fundamental concepts

Evolution is often visualised in terms of natural selection, sexual selection and genetic drift. However, when generalising Darwinism, there is another useful perspective, which can be obtained by considering evolution to be the result of a balance between the forces of production and elimination. This idea is best introduced by considering the following new categories:

  • Natural production - refers to things coming into existence.
  • Natural elimination - refers to things going out of existence.
These are extremely basic and fundamental principles. They neatly encapsulate the aspects of evolution that do not involve copying. They thus apply to both biotic and abiotic systems. To illustrate these principles with some abiotic examples:

Examples of natural elimination

Some examples of natural elimination:

  • Stars that are observed are the ones that have not previously burned out or exploded;
  • Atoms that are observed tend to be the stable ones - the ones with long half-lives;
  • Mountains tend to be covered in hard rocks - soft rocks there tend to get washed away.

Examples of natural production

Natural elimination is balanced by natural production. Some examples:
  • Stars are produced by balls of gas condensing;
  • Atoms are mostly produced from other atoms - by the processes of fission or fusion;
  • Mountains are produced by tectonic plate motion and erosion.

Observed frequencies

The frequencies of the things we observe in the world arise as a result of a mixture of processes of production and elimination. Things that are produced frequently and are difficult to eliminate are often observed - whereas things that are produced infrequently and are easy to eliminate are rarely observed. In my book I include a table of examples of these phenomena - including "tall coin stacks" - which are produced rarely and destroyed easily - and "pebbles", which are produced easily and destroyed relatively rarely.

If production rates exceed elimination rates, the number of entites grows - while if elimination rates exceed production rates, the number of entites shrinks. These ideas thus fit very naturally into the framework provided by population genetics.

Note that the approach here can be applied to anything with a measurable frequency. The entities do not have to form a natural kind. They do not need to be to be discrete or particulate either.

For example, you could consider the category of: "men over six feet tall". Production takes place during adolescence, and elimination takes place through death, limb loss, sex changes or degenerative osteoporosis. The results may be more interesting if dealing with natural kinds, but any system where you can measure the frequency with which something occurs can be analysed in this way.

Use in biology

Natural elimination and natural production are most familiar in the context of biological systems. There, production typically takes place at birth, and elimination takes place at death. If birth rates exceed death rates the population grows while if death rates exceed birth rates, the population shrinks. In living systems, natural elimination is selection by death. Natural elimination is a bit different from natural selection, thoug. For one thing, it makes no attempt to exclude genetic drift. The nearest familiar concept in biology to natural production is probably sexual selection. However, sexual selection is not a very general principle. It isn't just sexual organisms that are able to produce varying numbers of offspring. Instead the concept of differential reproductive success is sometimes used. Natural production is a more general concept than this though - since it can be applied to both biotic and abiotic systems.

Another way of considering the difference is to see that natural production is a kind of mirror image of natural elimination - in that production creates and elimination destroys. However, there isn't really any corresponding mirror concept for the idea of natural selection.

Since biological processes involve copying, what is naturally produced is constantly being magnified, while things that are naturally eliminated play an ever-diminishing role. Thus, iterative application of natural production and natural elimination can result in adaptive evolution.

Framing things in terms of natural selection and sexual selection reflects the way in which these ideas were discovered historically - but sexual selection is not a very general concept. Thinking in terms of natural elimination and natural production results in a more general and broadly-applicable framework - one that extends deeply into many kinds of abiotic systems.

Fundamental revisions

When taught at all, natural selection is currently taught in biology classes. Natural elimination and natural production should probably be taught first in physics (or mathematics) classes. These are pretty basic explanatory principles, broadly comparable in scope to the idea of entropy, or to self-organisation.

This material may seem very basic - and it is. However, it is not so basic as to be obvious. Something like it does need teaching to children in science classes - with presentation along the lines given here, and with natural selection in biology being given as an example of the results of these principles being applied to a system which involves copying.

For more about this topic, please see my book on Memetics - which is out now.


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