International Society for Science & Religion - Library Project

The Deep Structure of Biology: Is Convergence Sufficiently Ubiquitous to Give a Directional Signal

by Simon Conway Morris

Introductory Essay by Brian Heap

The concept of evolution as a process without path or purpose and achieved by descent and modification has given rise to the idea that its end points are indeterminate. In recent years, however, another idea has emerged with renewed force, namely, that certain aspects of evolution appear to be constrained. To explore this phenomenon, a meeting held at the Vatican Observatory brought together twelve renowned scientists, philosophers and theologians with the editor, Simon Conway Morris, whose book, Life’s Solution, features elsewhere in the Library Collection and is essential reading about evolutionary convergence and how it provides a counterpart to natural selection. 

Many specific examples are given in this volume - similarities of the camera-eye in the cephalopods and vertebrates which reached the same solution independently (rather than from a common ancestor that possessed such a structure). Other examples come from microbes, animals and plants, though there is a clear reluctance to infer general laws and principles, or some underlying biological ‘anthropic principle’ in a way that would be familiar to physicists and chemists. 

Empirical studies are reported which reinforce interpretations about the role of chance and necessity in the history of the life on Earth, and about extrinsic and intrinsic constraints imposed on organisms by physical and biological phenomena, respectively. Directionality favoured by De Duve, and unpredictability of contingent events by Gould are rehearsed, while the equation that scales mass as the third power of body length is seen as a strong exemplar of a history shaped more by the operation of natural selection than by random events.

But it is intelligence and its appearance in unlikely places in biology that holds most fascination. Plants with intelligent, decentralised behaviour respond and adapt to their environments in a form of intelligence that is found in all forms of life and which is central to the evolution of life itself.  This rebalancing of our understanding of the evolution of intelligence and mental characteristics from large-brained social primates to other large-brained social animals (eg cetaceans) and to large-brained social birds (eg corvids), supports the idea that intelligence is a process of convergence and adaptation rather than a product of common ancestry. It is driven by the need to solve comparable social and ecological problems.      

Trends in the human species which extend beyond those in any other primate or mammal do not necessarily represent a departure from general principles since they derive from the genome and phenotype.  Humans may be outliers but repetitive patterns which are found throughout the evolutionary process can be a means of coping with complex adaptive integration through constrained directional trends. This may simply provide an illusion of directionality or purpose but only because of the functionality and designed nature of the biological world. Yet, while some biologists think they will one day know all there is to know about the natural world, others argue that there is a niche of human intelligence that is self-limiting. So, while one contributor contends that science helps to liberate us all from myth, superstition and sophistry, another has a deeper hold of a story that ‘wends its way we know not where, but may, for all we know, be pregnant with the promise of ultimate meaning’ [230].