Last updated on 22 Jun 2018
Notes on Novelty series:
2. Historical considerations – before and after evolution
3: The meaning of evolutionary novelty
4: Examples – the beetle’s horns and the turtle’s shell
5: Evolutionary radiations and individuation
6: Levels of description
8: Conclusion – Post evo-devo
The roots of novelty in biology are very deep. They go back at least to Aristotle’s book De Anima (in Greek, ΠΕΡΙ ΨΥΧΗΣ), or as we know it in English, On the Soul (a readable version is this edition). Aristotle posited four grades of “soul” (a better term might be “motivating force”; it has very little to do with the Christian notion of a soul): vegetative (self-nutrition), sensitive or perceptual (sensation), motile (movement), and rational. These were arrayed in that order from most simple to most sophisticated (figure at right from Singer 1931). This led to what came in the late middle ages and early Renaissance as the scala naturae, the great chain of being. The least complex organisms merely grew. More complex ones responded to their environment. Even more complex ones moved about. Finally, one species was rational.
The great chain was tied up in kabbalistic thinking, alchemy, and the neo-Platonism that preceded and in many ways triggered the scientific revolution. Everybody assumed there were higher organisms and lower, and that plants were the simplest, as while they had parts and organs (were organ-ised, hence later, “organisms”), they lacked senses and motion. In 1745, Charles Bonnet tried to formalise what everybody knew in a single diagram (right) – the very act of doing so caused the project to crumble, although it took a while, and I would argue is still with us. Old ideas, as Dewey said, fade away, but they sometimes die hard.
But the great chain caused no problems of novelty, because it was static. The array of forms and functions was what it was because God had made it so. Since it was the consensus that novelty of design came from a designer (Sedley 2007), there was no problem of novelty except to those theologians who thought God was simple. God’s mind captured all possibilities, and so he chose the special functions of each kind of organism.
The problem of novelty arose when the scala naturae was temporised; when functions were acquired and complex structures developed over time. However, there were several solutions to this. One was entelechy – an internal disposition of stuff to become more complex, usually because God made it for that purpose (this view can be traced back to Augustine). Another is the view that Lamarck is widely, and unfairly, known for formally stating (but which he did not invent): organisms acquire functions from the environment and geography as adults, and pass them on to their offspring. These both involved what theologians called “secondary causes”, by natural law and causation. Occasionalists thought that God intervened providentially at each juncture (Wilkins In press).
Lamarck, and his immediate earlier predecessor Erasmus Darwin, however, held to material causes for evolution, and so the solution to the problem of novelty had to be equally material. For Lamarck there was a feu ethere or subtle fire that drove things to become more complex. Again, this could be understood as built into the universe by God, and hence a secondary cause. Later thinkers like Herbert Spencer had similar views: the universe was just such that it got more complex over time.
Charles Darwin, however, set the cat among the pigeons. Natural selection was an unguided process that generated novelty without a plan of any kind, and indeed, as I show in the Zygon paper, God was thought not to be able to guide evolution by natural selection without undermining the entire notion of doing science. If we allow some occasionalism, as Darwin’s friend and advocate Asa Gray did, where do we stop?
In the 1930s, a movement began that talked about a new concept: emergence. The underlying ideas were older, of course, and went back to the 19th century with John Stuart Mill, but began to attract attention with C. D. Broad [chapter 2], Samuel Alexander, Jan Smuts and C. Lloyd Morgan. In recent years, much has been made of emergent properties in the philosophy of mind, as a way to avoid dualism but avoiding physicalist reductionism.
Emergence is variously defined, but it broadly means that a qualitatively new property arises out of the whole system of physical interactions in ways that cannot be reduced to statements about the components of the system. It has become popular since the 1970s to claim that there are evolutionary properties that are not something one can reduce to statements about genes, cells or even the properties of individual organisms.
For many years this played out in the philosophy of mind, including the development of the notion of supervenience by Jaegwon Kim, and which was applied to evolution first by Elliot Sober I think. In recent years, emergence has also been applied to evolution again. Now it is tied into the idea that evolution undergoes “major transitions”. In the modern synthesis, the idea of an “adaptive novelty” leading to “evolutionary radiations”, was widespread. Here the novelty opened up ecological niches not available before it.
With the major transitions literature, however, the novelty was of a particular kind: it was information transmission. Now it was information that was the emergent novel property, and the major transitions were advances in the transmission machinery:
[Maynard Smith and Szathmáry 1995:5]
In a more recent work, the differentiae are clearly informational: Jablonka and Lamb 2005 argue that there are four dimensions of information transmission – genetic, epigenetic, behavioural and symbolic. Each of these represents a source of evolutionary novelty.
What is most salient about these lists is how much they resemble Aristotelian ladders. It is not that any of them are unreal; clearly compartmentalisation, chromosomal packaging, epigenetic mechanisms and so on all did evolve. The real question is why they, and not some other set of properties to do with, for example, energy efficiency (such as the evolution of mitochondrial phosphorylation or chloroplast photosynthesis), are the major transitions. It looks, for all the world, that out of the diversity of evolutionary novelties we have chosen as our “major” transitions those features that matter most to us as symbolic language users. In short, this looks like anthropomorphism.
In the next post in this series I will discuss the definitions given of evolutionary novelty.
Bonnet, Charles. 1745. Traité d’Insectologie ou observations sur les Pucerons. Vol. 2. Paris: Durand.
Jablonka, Eva, and Marion J. Lamb. 2005. Evolution in four dimensions: genetic, epigenetic, behavioral, and symbolic variation in the history of life, Life and mind. Cambridge, Mass.: MIT Press.
Maynard Smith, John, and Eörs Szathmáry. 1995. The major transitions in evolution. Oxford, New York and Heidelberg: WH Freeman/Spektrum.
Sedley, David N. 2007. Creationism and its critics in antiquity, Sather classical lectures. Berkeley, CA; London: University of California Press.
Singer, Charles Joseph. 1931. A short history of biology: a general introduction to the study of living things. London: Abelard-Schuman.
Wilkins, John S. In press. Could God Create Darwinian Accidents? Zygon.