Language for Talking, and Thinking, About Evolution

A lot of people recognise that the language we use to talk about evolution is, if taken literally, quite inaccurate. The following are some musings, hastily written up, on how to more accurately describe what is going on. I haven't thought these things through much, and I haven't really looked at whether the suggested alternatives would be suitable for practical situations (like considering whether they are too unweildly or not).

Use 'Situation' instead of 'Environment'

We talk of the creature's environment setting up the selection pressures. Properly understood, there's nothing wrong with this. At the same time, I think the conception of 'environment' most people have can mislead them when thinking about this. The term 'environment' can conjure up the environment of the landscape around the creature, the other plant and animal species. That it can tend to obscure is that the other members of the same species are part of the environment, and that the results of the creatures own behavior is also part of its environment. I think it can also obscure the fact that the environment is not just the physical place, but the unfolding and changing environment over time (over time the selection pressures will change). For these reasons, I think the reality is better captured by the term 'situation'. The creature's situation sets up the selection pressures.


Use 'Optimize' rather than 'Increase'

We tend to say that evolution works to increase a entity's fitness. I think there are two reasons why this can be misleading. It implies that there is some one dimensional value that is being increased... which is okay if you understand that value as an "abstract" fitness. It's just that it doesn't capture well the multidimensionality of the factors that actually make the difference to survival and propagation. "Increase" also suggests a ladder and some path of progress... but this is a bit misleading. For fitness is always relative to the current environment, and what is fit will change as the environment changes. It is not so much that we have steadily increasing fitness, but that the system's fitness "tracks" the changes in the environment. (this is not to say that because 'localized changes' don't always lead to greater general sophistication the biosphere will not end up creating greater complexity over time). For this reason, I think that it is better to talk of creatures fitness being continually optimized rather than continually increasing.


Talk of Natural Selection and Evolution as Products Not Forces, and of optimization potentials instead of implicit goals

When we talk of evolution at work, we tend to say things like "evolution created eyes so animals could hunt their prey". This language is inaccurate because it implies there's an active force pushing, or trying to push, the evolution in a particular direction. But natural selection and evolution is not so much a force that does things, but the product of certain types of situations.

It's the product of situations containing the three factors of variation, heridiblity of that variation, and, basically, competition for survival. When these three factors are present, natural selection and the evolution of forms are the consequences. That is, the natural selection process and the evolution of forms are emergent phenomena.

I started reading Stuart Kauffman's At Home in the Universe last night, and I think there is some of this confusion about evolution in his consideration of how self-organising systems relate to evolutionary processes, though I don't have time to go into the details here (so you can ignore this statement if you want :-)).

We talk of creatures, or evolution itself, evolving some feature for some purpose. This is really just a way of talking and is quite inaccurate. Creatures can't direct their evolution like this, and neither can evolution itself. Evolution does not have goals, and even if it did, it doesn't have any foresight that it could use to reach them. (thinking about evolution as if it did have goals and/or foresight seem to be very common problems). We can much more easily see this when we understand that natural selection is an emergent phenomenom, and I think part of the reason this problem occurs is because of seeing it as some sort of force at work.

It seems difficult to talk of evolution without talking about goals. We talk of evolution as coming up with solutions to problems (it's goals are to solve those problems). What's really going on, however, is that a particular situation provides certain opportunities for creatures to evolve in certain ways. That is, in any given situation, there might be various ways that a creature could potentially evolve that would improve its fitness. If the appropriate mutations happen to occur, the species will move in one or more of those directions. So it's not so much that there is a problem to solve -- a goal to be attained by solving it -- but that the environment possesses opportunities that creatures can happen to evolve towards. I would describe these opportunities as optimization potentials (and remember of course that any change in the environment, including the evolution of a particular species, may change the optimization potentials for it). So natural selection may end up meeting optimization potentials. So perhaps you can say something like "the unfolding situation made use of an optimization potential to evolve feature Y in Xs".

So we can say stuff like "The situation selected for Y", "Optimization emerges from a situation", "Xs evolved feature Y by natural selection's optimization".... but as I said at the start I haven't really thought about using this language in a practical context... and I don't have time for this right now.