Purpose in Biology

I couldn’t resist giving my two cents again over at Pharyngula. PZ Myers criticized the biologist and intelligent design theorist Michael Behe’s understanding of purpose in living systems. I’m not at all on board with Behe’s overall project (as you’ll see below), but I do think he is focusing on the right shortcomings in the standard Darwinian/mechanist account of evolution.

Behe is right to focus on complexity and purpose in his critique of the neo-Darwinian synthesis. Before I explain why I think these are the crucial phenomena for any evolutionary theory to explain, it should be made clear that within biology, there are many distinct paradigms studying the evolutionary process, including evolutionary developmental theory, complex systems theory, niche construction theory, structural coupling/autopoietic theory, etc., and that each of these paradigms focuses on aspects of the process that a strictly Darwinian account leaves out. So while I agree with Behe’s criticism of one of these paradigms, I think his suggestion that Darwinism’s lack of a complete explanation for evolutionary phenomena demands postulating an intelligent designer is off the mark. Biology has other lenses than the Darwinian that allow it to understand the emergence of complex and purposeful organic structure and function without reference to design.

Notice that I refer above to purpose as a phenomenon, which is to say that purpose, or telos, is an observable feature of any living system. It isn’t a concept or an idea projected by humans onto organisms; it is an objective fact about what it means to be alive, whether that life be human or prokaryotic. Purpose is not to be defined as something added to a living system from outside by a designer (be it a supernatural or a natural designer). Rather, purpose has to do with the self-organizational dynamics seen in all living systems. This is not an original insight of Behe’s. Kant wrote in the Critique of Judgment more than 200 years ago that there would never be a “Newton of the grass blade,” because unlike the inorganic systems that Newton was able to mathematize, organic systems are, as Kant put it, both cause and effect of themselves. Machines and other inorganic systems are structurally allopoietic (other-caused), whereas life is universally an autopoietic, or self-producing process. For a system to be cause and effect of itself does not mean it functions independently of its environment. Self-organization refers to the formal, or logical structure of a system, not to its material structure. On the material level, of course the organism is completely dependent on outside matter and energy for its continued survival. The significance of its formal, self-organizing structure consists in the way in which this outside material is transformed into the complex body of the organism in question. In philosophical terms, there is no strictly mechanical way (in terms of efficient causation) of explaining how inorganic matter takes on organic form. To adequately account for living beings that produce their own internal components and a selectively permeable membrane that continuously distinguishes them from their environment, one also must make use of non-mechanical forms of causality, specifically formal and final causality. The emergence that takes place on the molecular level to bring forth a living cell cannot be explained by reference to the parts, or the molecules, alone. A further explanatory principle is required to account for the way in which the components of an organism each work continuously to produce the organized whole of which they are a part.

These holistic and purposeful aspects of life require not the ad hoc hypothesis of a supernatural designer, but the re-appraisal of the materialist ontology that both Behe and Darwin share. That Behe may believe in a deity entirely above and beyond nature makes no difference for the way he conceives of natural beings in much the way Darwin did, as complex machines. What is needed, I think, is a cosmological picture wherein finality and formal causality are as natural as the mechanical causes science has been studying since Galileo. Not an external designer, but a principle of immanent purposes (much like Kant developed in the CoJ) may allow future biologists to overcome the false dichotomy between complete randomness and providential design. Perhaps the divine is not an all-powerful dictator above and beyond nature who shapes every atom and every animal from a pre-conceived plan, but a creative participant in the evolutionary journey of matter from initial simplicity to eventual complexity. In short, perhaps God is more of a lure toward beauty, an Omega toward which the evolutionary process is persuaded but not forced, than an architect who set it all up in advance.