Epistolution Musing №5: Genetic Assimilation
Dear Friends,
This letter is part of a weekly series of brief thoughts I would like to share with you, either because I’ve come across your related work in biology or because you’re a person I like. I discovered an interesting problem in 2019, a problem I can’t forget. Epistolution is the unknown biological mechanism necessary to explain purposive activity that can’t be accounted for by genetic influences.
Recap: Since the divergent purposive behavior of twins demonstrates that genes don’t control learning, we can assume that new functions arise from a process underlying all life. If this is true, we can rule out survival and reproduction as the primary aim of life. I conjectured that instead organisms are trying to update their causal map of the world. Last week we talked about how I believe this purposive mechanism, when discovered, will be the basis for a technological explosion of recursively self-improving moral machines. Previously, on a more prosaic level, in Musing №2 we discussed how epistolution finds attractors by choosing certain sets of genes to turn on or off during development. This week we look at what this might mean for evolution.
In 1942, a biologist named Conrad Waddington exposed developing fruit fly embryos to ether. In response, some of the flies developed double thoraxes. Waddington, with a devious curiosity, then continued the experiment, artificially selecting the double-thoraxed flies for twenty generations. After this procedure, Waddington was able to make the double-thorax trait appear in the flies without the ether treatment. This process he called “canalizing selection” of a trait, and it meant that, at least in some cases, the plasticity that an organism showed in development could lead the evolution of the genetic code in a particular direction.
Even after eighty years, the theoretical significance of this experiment has not been fully explored. All organisms begin from one cell, and in many species the cell then divides and differentiates into many cell types. This happens because particular stuff is applied to the genome to promote or suppress the expression of various genes. This process is called epigenetics. Epigenetics is how cells “decide” what to be and how to behave. All the important differences in cellular behavior (and therefore organismic behavior) are really a consequence of certain epigenetic stuff being stuck onto the genomes of cells. This means that learning is a consequence of patterns of epigenetic marking as well. Learned behaviors and traits lead an organism toward a particular style of life, and likewise its offspring. As generations of organisms continue living in that style of life, natural selection acts on the organisms and on their random genetic mutations. Over time this may change the genetic code to better support their survival and reproduction in their learned style of life. In this way, learning could often lead directly to genetic evolution.
For instance, to reintroduce a tired evolutionary example, consider the giraffe’s neck. Let’s say that a giraffe learns that reaching high into the canopy provides her with a better, more nutritious bite of food. How to choose between leaves is certainly something that giraffes learn, and an Anna or Amanda giraffe would learn it differently in different forests. After having learned this, the giraffe has then adopted a lifestyle within which some selection pressure will be exerted on the genome to eliminate mutations that shortened the neck and spread mutations consistent with long necks. Without the learned behavior leading the way, no such selection pressure would exist and the giraffe would remain short-necked by default. This mechanism makes it virtually certain that evolution can be explicitly directed by learning rather than by random genetic mutations only. The simple point here is that genetic selection is applied after, not before, learning. This fact becomes deeply significant if we do away with the assumption that learning is a genetically coded trait. In this case, learning itself actually directs evolution.
Waddington, although he discovered canalizing selection, was still convinced that genes themselves controlled learning. In his book, The Strategy of the Genes, he writes in a piercingly insightful way about the effects of epistolution while still remaining convinced that epistolution was a result of the natural selection of genomes. But this mistake does nothing to weaken the meaning of his discovery; he simply discovered something more significant than he knew at the time, as most great scientists do. Discarding a blind faith in selection was probably not an easy attitude to adopt before the molecular details of genetics were worked out in detail, especially since even today we don’t know how epistolution physically works.
The learning-first alternative is actually much more plausible than the Neo-Darwinist idea that evolution is led only by random mutation and random contingencies. Learning is vastly more likely to arrive at solutions quickly than a truly random exploration of genetic combinations. The strongest explanation for evolution thus involves a combination of selection and learning. Learning is used to target the style of life that works, and selection is used to cement that style of life into the genes where it can be recreated more easily as an attractor. And none of this prevents truly random mutants from occasionally being adaptive.
Once this mechanism was uncovered by Waddington, it should have shifted the burden of proof in biology. Waddington’s experiment was conducted thirty years before The Selfish Gene was published. If the implications of genetic assimilation were properly considered, the burden of proof would have shifted to the selectionists like Richard Dawkins to show that epistolution provides no more reproductive benefit than the random mutation of genes. Instead of assuming that plasticity evolved through random mutations, we should be assuming that evolution begins with epistolution, and that natural selection among random mutants are how the solutions uncovered by epistolution are assimilated into the genetic code. Now, of course, there is emerging evidence of direct epigenetic inheritance, which further weakens selectionism.
Beyond the technical error in interpretation that was committed, this mistake has deep spiritual consequences as well. The meaning of this shift could not be more profound for us as living beings. A learning-first view of life would mean that instead of being “lumbering robots” controlled by our random contingent genetic inheritance, we are leading our own evolution toward better solutions by finding them ourselves. The decisions we make as beings, instead of being empty programs determined by DNA, would show themselves as creative, positive, constructive searches for value. If we combine this concept with the assumptions we have already made about intelligence, then it means all living beings are searching not only for selfish reasons to survive and reproduce, but for ways of understanding the world and improving their ability to do so. It means all beings are grasping, in their eccentric local ways, for the truth.
Be Kind, and Be Brave,
Love, Charlie posted to Medium 1/11/24
