The philosopher and chemist Michael Polanyi wrote about “life’s irreducible structure” back in the 1970s (add ref…). He pointed out that a higher level of complexity could not be explained in terms of the lower levels. A wave can’t be described in terms of water molecules. A human, with all of its intricate, integrated physical structures, thoughts and emotions cannot possibly be explained in terms of mere molecules, not even DNA. A living human manifests emergent properties far beyond the sum of its molecules. The linguist Noam Chomsky made the same observation in terms of human language capability. He wondered how biologists could explain the stunning complexity of language competence, a unique characteristic shared among all humans (and to a lesser extent shared with our primate relatives, and apparently some other vertebrates). Language, he pointed out, comes from a biological source and biologists ought to be able to explain it (add ref from Campbell…?). It is impossible to see how natural selection and adaptation are capable of providing an explanation by themselves.
Is language adaptive? Of course, but being minimally adapted for life on Earth is another conditional statement defining that very life. Non-adapted life never lived here. Again, the Covering Law Model can help to clarify. Now, one of the explanans is living systems, which by definition are adapted to survive on our planet (and are also able to replicate, etc.). For the other explanan we have adaptation acting as a law of nature. The event we’d like to explain in the explanandum is evolution, but because one of the explanans is actually part of the other, we end up with a circular argument, a tautology. The conjunction of the explanans tells us that adaptation is adaptive. Thanks, but that wasn’t the question – evolution is still left unexplained. (I think a similar critique of adaptation as the sole causal explanation was made in Gould et al. – Spandrels of San Marco…find ref.)
Evolutionary events, both speciation and development, must involve the intake of information from the outside environment for competent organisms to result. So, adaptation is involved, but how this works is not clear. This idea has changed form, from Lamarck to Taborsky, (more on this in a later chapter). Adaptation is necessary, but not sufficient. We need to explore additional possibilities in order to explain the existence of self-organization in bacteria, let alone human language, and the idea of emergent properties is central to this.
Historically, our difficulty with emergence has stemmed from our refusal to reject both determinism (the universe is as predictable as a mechanical watch) and reductionism, a system of false explanation that attempts to reduce all levels of complexity to some simplistic “common denominator” (to molecules in the case of biology). There is something seductive and almost irresistible about reductionism; the simplest equation that strips away what is considered superfluous, leaving only the central kernel of relationships. A different version of simplicity’s strength is known as “Occam’s Razor,” or parsimony, which says we must restrict the explanation to the evidence provided – no making things up; no unnecessary embellishments. This is not the same as reductionism, which often goes too far, ignoring relevant evidence because it adds messiness to some tidy summation. The pristine equations of population genetics, for example, are beyond simple – they’re simplistic. Is there inherently greater accuracy in the shorter equation? No, especially when it omits important pieces. There is no particular relationship between truth and brevity (or truth and beauty, for that matter). The problem is this: reductionism doesn’t work. No direct bridge (in the sense of the Covering Law Model) can logically be made between a molecule and a bacterium, let alone a molecule and the spoken expression of an idea. Too much is left out. Other ideas deserve exploration, such as concepts of self-organization, increasing complexity and emergent properties, where a new level of organization emerges from earlier levels.
The whole is obviously, logically, demonstrably more than the sum of its parts. This is one of the properties of living and non-living systems that we must seek to understand. Acknowledging emergent properties as a natural feature of our universe does not in any way require the invocation of mysticism or the intervention of any deities. Conversely, present day explanations of how we get from DNA and cytoplasm to fully functional organisms are so feeble that magic is almost a requirement. To me, this suggests we have been looking in the wrong places, at theories with a certain amount of emaciated “elegance,” but insufficient explanatory power. We should admit that traditionally accepted theories can’t be the whole story and we must (if our goal is to understand) seek to expand causal explanations life and the evolution of life.
To biologists, the lack of a robust causal explanation for the systems they study should be deeply unsatisfying. Various biologists have taken evasive maneuvers and suggested that biology is “different” from the other branches of the natural sciences. Nonsense. Granted, biology deals with extraordinarily complex systems, but that’s all the more reason we want a clear, scientific approach. It’s really quite surprising that there have not more objections from the scientific community or that more time has not been spent openly exploring alternative theories of evolution. Competition and natural selection exist, but they are secondary players in that communities of life must already be in place before these forces can have an effect. Natural selection surely has an impact on living systems (I can’t help but think of the hilarious “Darwin Awards.”), but it didn’t cause life to come into existence and it doesn’t drive evolution. Perhaps our general failure to seriously explore alternative explanations is due to a fear of creationism. But the unwillingness to consider emergence and other phenomena that help to explain evolution (and many other natural events) only makes biological science weaker. It is not evolution or the emergence accompanying it that should be rejected, but biologist’s enduring, irrational faith in natural selection as the only contender for an ultimate, underlying driving force.
We need a theory of morphogenesis, an explanation for the self-generation of living forms. We know quite a bit about DNA and genes, but getting from there to organisms is a “black box.” It’s not enough to note that development just happens. We need a theory of morphogenesis in order to develop better theories of evolution because evolution can only be expressed through the self-generation of living forms.