“Larvae, the immature forms of many animals, are distinct from adult forms by definition. In many life histories–caterpillars and the trochophore larvae of clams and sea snails are examples–larvae and adults bear no resemblance to each other. Biologist Donald I. Williamson has proposed that larvae are juvenile forms acquired through hybridization–the fusing of two genomes, one of which is now expressed early in an animal’s life, the other late. This hypothesis, which goes against traditional thinking that branches on the evolutionary tree cannot fuse to form chimeric species, is one of several possible solutions to open questions about the evolution of larvae. Although an experiment did not yield convincing DNA evidence, the hypothesis is consistent with certain patterns seen in the distribution of genes across species. Along with other evidence of cross-species hybridization, it implies a pattern of evolution that looks more like a network than like Darwin’s tree of life. Until he retired in 1997, Williamson was a Reader in Marine Biology at the University of Liverpool. He is the author of two books on the origins of larvae. His coauthor for this article is Sonya E. Vickers, a teacher and naturalist.” [See Differences in the forms of larvae and adults may reflect fused genomes by Donald I. Williamson and Sonya E. Vickers]
The different species are not so well-separated as even evolutionary biologists would have thought a few decades ago. Even if this particular hypothesis of chimeric hybridization between species is wrong, there’s still clearly something going on here that doesn’t fit with our simple ideas of what a species is. Our cell-membranes and skins don’t do as good a job as we might hope at keeping us in and them out. It’s even plausible that different species can merge to share the same soma or body-mass. This is a conceptual problem at various levels, including our concern for understanding what sorts of entities we human beings are. We can say at least this much: whatever our fate on the other side of our graves, we are fully a part of this universe, this phase of Creation, so long as we remain in our mortal lives.
Biologists discovered long ago that our DNA includes such junk-code as genes for making proteins for our apish ancestors. It also includes junk-code inserted by viruses or retroviruses, even the reverse-transcripted DNA or RNA for some of those microorganisms. There’s no empirical evidence that we are inherently transcendent to this world of blood and mud, no empirical evidence that we are anything but peculiar members of the animal kingdom. In some sense, we’re still part ape or even part reptile or — still more radically — part bacteria.
Yet, it’s surprising that someone could even speculate plausibly that two creatures can share a body, one living for part of the total lifetime and melting away inside a cocoon to provide the gunk from which the other creature is shaped. In a sense we already knew this about creatures, such as butterflies, which pass through a larval stage, but now we know more. We know that there may be two separate sets of genes involved, that is, sets of genes originally from separate complex species. But are they really two creatures or different phases of one?
After all, our cells and the cells of all known bacteria and plants and animals are powered by mitochondria which were once separate creatures before being absorbed by an ancient ancestor of ours. Are mitochondria still separate creatures in some sense, perhaps slaves of our cells? I doubt if anyone would seriously support that idea. Why would we think the larva and the caterpillar to be separate creatures? One reason might be the belief held by many that a human person is defined by his genes and that person comes into existence as soon as a complete set of viable genes exist in a fertilized egg. Suppose that the larva has one complete set of genes that are shut down as it enters its pupal stage. As that transitional stage progresses, another complete set of genes is activated and another creature comes to life, so to speak. Again, it’s far from certain this is the best description of the situation, but it’s currently plausible and that alone should raise some questions. If that larva and that butterfly can be coherently described as separate individuals, our own individuality may not be what we think it to be.
This speculation is another nugget of knowledge in conflict with many of the theories about human nature, especially when those theories have been drawn, however unconsciously, from modern liberalism’s teaching that we’re some sort of autonomous human person from birth to death. My Thomistic beliefs that the human mind forms by responding to its environment and also to its own body imply that we can change in very fundamental ways throughout our lives. A conversion, spiritual or moral or intellectual, may lead you down a path where you have a radically different mind than you would have otherwise had. Are you then a different person?
Suppose our bodies are changed in a significant way? How deep do those purely physical changes go? Are you truly a different human being if a virus invades and changes your genes, or at least the population of activated genes? How about changes induced by some sort of radical gene therapy or by psychiatric drugs? How many of your organs can be transplanted without you becoming a different human being?
In Rewriting the Soul, the philosopher Ian Hacking had speculated that the multiple personality phenomenon is a largely learned strategy of segregating painful memories. Is our sense of a particular individuality tied that strictly to specific memories? But our memories would not seem so separate from a specific physical body, with a specific set of organs and specific sets of genes that are activated or de-activated as needed by that body.
It’s established to a high degree of certainty that we don’t initiate many of our actions that we experience as being consciously willed. (See Is This Evidence Against Free-will?.) Our bodies move and act apart from our conscious parts to a greater extent than we realize. Our nerves and our muscles, our hearts and lungs, are parts of our moral selves and not just stage-props. Questions about our bodily nature have moral implications as well as practical implications which probably are far more important that our moral worries with our conscious selves. Our conscious selves probably are most important in their ability to shape our future unconscious selves. That is, we can change our human beings, the ‘wiring’ of our nerves and the development of our muscles and our cardiovascular systems, and those changes become part of our moral selves.
When we talk about human beings, we’re now in a position where we literally don’t know what we’re talking about. We’re at a transitional point where we’ve learned a lot about human nature at the species level but we haven’t absorbed that knowledge into our everyday languages, Christian and non-Christian languages alike. In fact, our words and concepts about our individuality, our ways of making decisions or forming relationships, are in very bad condition. Many of our philosophical and theological words and concepts are from once rational but now outmoded ways of looking at the empirical reality of human nature, but our views of our individual selves, and our social selves, have been downright deformed by a lagged adoption of the radical individualism of modern liberalism. That is, today’s Christian who thinks he’s a moral traditionalist has ideas which come from Hobbes and Locke and Jefferson as well as from truly Christian lines of thought.
I’m not the only one who sees these problems though I might have a unique perspective. Others, scientists and poets, philosophers and theologians, musicians and historians, have been working on this problem of re-aligning our thoughts and speech with the reality of human nature and the greater realities of our universe, but thinkers who work specifically from inside the Christian faith don’t seem willing to deal with this explosion of modern empirical knowledge. I’m trying to grapple with this new knowledge with an openminded attitude similar to that of St. Augustine of Hippo and St. Thomas Aquinas.
Even the best of Christian thought has been corrupted for centuries by a Manichaeistic lack of respect for God’s Creation. Until Christian thinkers purge themselves of this lack of respect, until they nurture an openminded attitude towards this universe, Christian thought will be marginalized and mainstream cultures will be lacking in a proper Christian element. In fact, with a distorted view of physical reality, Christians won’t be able to see this world created by God because that world is the physical universe seen in light of God’s purposes.