One of the strongest arguments Darwinists use is based on the fact that many different creatures look similar to each other in some fairly foundational ways, including sometimes in the genome itself. Even Michael Behe (of Darwin’s Black Box fame) believes in common decent in part because of a broken gene that is found in both chimps and humans. The assumption is that if some feature is the same in two different population groups, they must have a common ancestor with that same feature.
It is certainly plausible to assume that common features indicate a common cause, and common decent is one possible way that that could occur (whether likely or not is a different issue). But it is by no means the only way. Indeed, a common environment could just as easily explain certain common traits. That is, suppose that a gene is mutated due to radiation in the environment, and two species have that same gene and share the same environment. There is a good possibility that the gene will be mutated identically in both populations simply because of the environment, and it has nothing to do with lineage.
Naturally, I’m not saying that’s what happened with the broken gene found in both chimps and humans. I haven’t studied that particular issue enough to know either way; but I do know enough to not assume ipso facto that commonality must require common decent. Indeed, there is a specific example of which I am familiar that demonstrates just how dangerous it is for scientists to dogmatically claim decent in such a manner.
It’s called the marsupials of Australia (they also exist here and there in South America and Asia, but they reign in Australia).
Marsupials differ from placental mammals in that marsupials will give birth to their young prematurely, and then the offspring will move into a pouch (called the “marsupium”) in females, and they be raised in that pouch until they are fully developed. In contrast, placental mammals carry their offspring to full term before birth. These differences result in some anatomical differences, mostly in soft tissue, between placental mammals and marsupial mammals.
That said, there are many marsupials that look virtually identical to placental versions of the same animal, as pointed out in this article:
In some cases, placental and marsupial mammals physically resemble each other: the pouched marsupial mouse and the harvest mouse, the marsupial mole and the common mole, the marsupial wombat and the marmot, the tasmanian wolf and the wolf.The comparison between animals is such that, for instance, in the case of the wolf it is virtually impossible for the untrained eye to tell the difference between an Australian marsupial wolf skeleton and a European placental wolf skeleton.
Let us assume Darwinism is true for this argument. If we see a marsupial wolf that looks almost exactly like a placental wolf, we would immediately argue that this proves that marsupial and placental wolves had a common wolf ancestor that diverged into two lineages: one placental and one marsupial. And indeed, for a time, this is what Darwinists believed. Likewise with the marsupial mouse and the placental mouse: they too would have had a common mouse ancestor that diverged into two lineages.
But Darwinists must also consider the case of the wolf and the mouse together. The assumption is that since both are mammals (regardless of whether marsupial or placental animals are in view) then at some point each had a common ancestor that diverged into different lineages, one of which lead to the mouse line and one of which lead to the wolf line. Thus far, the Darwinist is not in any trouble.
The problem comes when he tries to handle both of these. The Darwinist needs to account for how both the wolf and the mouse diverged into marsupial and placental lines. It seems fairly logical to say that the differences between a marsupial wolf and a placental wolf are not as extreme as the differences between a wolf and a mouse (after all, even the untrained eye can distinguish between the skeleton of a mouse and the skeleton of a wolf despite not being able to distinguish between the marsupial and placental skeletons of a wolf). This would mean that, in order of precedence, the mammal lineage should have split into the mouse lineage and the wolf lineage before each branch then split into placental and marsupial lineages.
Yet that would mean that the marsupial split needed to happen multiple times. Not just twice, but there are about twenty such species that have marsupial members with corresponding placental members, and there are also several marsupial species that only exist as marsupials.
To make matters worse, even if we could stipulate that for some unknown reason, marsupials just happen to arise a lot in the fossil record, we also have to deal with the timeline. Australia and Antarctica broke off from Gondwanaland roughly 45-80 million years ago, according to which modern geological timeline you pick. As most of us have heard repeatedly, dinosaurs ruled the world until about 65 million years ago, and the only mammals alive at the time were small shrew-like creatures. This means if we assume Australia broke off only 45 million years ago, mammals only had 20 million years to co-evolve before those mammals on Australia were isolated from the rest of the world. If Australia broke off closer to 80 million years ago, we’d only have those shrew-like creatures to develop all the species of marsupials in Australia.
Which is it? Well, today most Darwinists on this issue believe all the marsupials in Australia have come from just one species: microbiotheria. In other words, Darwinists today believe that the marsupial/placental split only happened once. After that, placental mammals developed into the wide variety of animals that exist in Europe and North America, and the marsupial mammals developed into the wide variety of animals that exist in Australia and parts of South America. In the meantime, certain lineages just happened to evolve such that the Tasmanian wolf looks exactly like a European wolf to all but the trained observer. And the marsupial mouse looks like the placental mouse. And the placental flying squirrel looks like the marsupial flying squirrel. Etc, etc, etc.
Never fear though. Darwinists already know about this and have proposed an explanation! It’s called convergent evolution. Convergence is the idea that two organisms from separate species follow similar evolutionary paths due to identical environmental pressure. Thus, according to Darwinists, there was one species on Australia that also lived on the rest of the continents with mammal life. Because the environment was similar, the decedents of organisms on either side of the divide both evolved along similar pathways, to the point that the marsupial wolf, mouse, mole, and squirrel look almost identical to the placental wolf, mouse, mole, and squirrel.
Unfortunately, Darwinists don’t see how this undercuts their best evidence for common descent: the similarity of features. For you see, one broken gene that is the same in chimps and humans is proof of common decent, but having an entire skeleton that looks indistinguishable to another organism isn’t proof of common decent—it is proof of convergence. I would think that if the environment is sufficient to explain widespread morphologic similarities between marsupial and placental mammals, it must be sufficient to explain one broken gene.
Yet when you consider the vast difference between a mouse and a wolf, there is really no reason to think that an environment that would so alter the reproductive system of certain types of mammals—such that one becomes marsupial and one becomes placental—that that same environment would somehow “magically” zero in on the exact phenotype of the wolf or mouse. Indeed, on Darwinian principles alone, would this not actually suggest that given a shrew-like mammal on Earth, it was inevitable that wolf-like creatures would come about? Doesn’t all this suggest some kind of teleology? It certainly doesn’t seem to make sense from a process of random mutation followed by natural selection. That may get you the difference between placental and marsupial mammals, but it certainly cannot explain the existence of similar placental and marsupial wolves, given how far along the Darwinian lineage they each are from their shrew-like predecessor.
Peter,
ReplyDeleteAre you actively trying to ruin "Evolutionary Christian Spirituality" with blog posts such as these?
Why would you do that?
See this blog post about "Christian" theistic evolution titled "Spirituality and Faith in the 21st Century."
Excerpt(But do read the rest):
"The vision of the congregation that I am currently serving is to “teach and practice evolutionary Christian spirituality”. Following in the footsteps of Jesuit priest and paleontologist, Pierre Teilhard de Chardin, we are carrying out a grand spiritual experiment that is an inquiry into what Christian community, mission, and spiritual practice looks like when it emerges out of an explicit belief in evolution as a sacred or divine impulse. As a scientist, Teilhard de Chardin accepted the evolution of matter and of life on earth as fact. As a theologian and mystic, his strong intuition and personal experience was that the push and pull of the evolutionary impulse was infused with the presence of Christ, at both the exterior level of forms and the interior level of consciousness.
He celebrated the human being as an occasion of evolution awakening to itself – the subjectivity or interiority of the cosmos – and that this awakening represented a momentous leap forward for the human species. Yet, the liberal church, let alone fundamentalist Christianity, is either slow to integrate the sacred dimension of evolution or actively hostile to this notion.
Evolution is perhaps the fundamental characteristic or dynamic of reality. Either “God” or “Spirit” is involved with reality as we now know it to be, or It/She/He is largely irrelevant. Somewhere between the ideology of scientific materialists, such as Richard Dawkins, and the proponents of young earth science, lies rich theological soil to be tilled. We can, without too much metaphysical baggage, posit that God is present in the evolutionary processes of nature, consciousness, and human society as a non-coercive or persuasive bias for increased unity, differentiation, and subjectivity – (an evolution towards increasing compassion). This kind of conversation between science and spirituality represents just one facet of what you refer to as the transdisciplinary environment of the 21st century. If spirituality is to play a role in the transformation of the human species, its leaders must allow its theology and spiritual practice to influence and be influenced by the entire range of social systems – an orientation that theologian, H. Richard Niebuhr, called “Christ in culture” (as distinct from the traditional stance of Christ against culture).
(cont.)
But beyond whatever theology of evolution we employ, for me there is a direct mystical dimension to evolutionary spirituality. When I center myself deeply and regularly in a practice of identifying with the sacred evolutionary impulse, I gain an expanded sense of myself that is cosmic in scope, at one with all of creation, and with Spirit. This practice gives rise to a Christ that is cosmic in scope and yet intimately related to all of life. As well, I experience an undeniable mandate to realize my full potential for freedom and fullness of life – a sense that there is a unique future that cannot be born without me. Barbara Marx Hubbard calls this “vocational arousal”, and when an entire community collaborates to act from this energy, tremendous creativity to shape the future is released. From this Big Self, (the heart and mind of Christ), personal agendas give way to a cosmic agenda of being the new thing Spirit is doing, individually and collectively, as an act of service. Or, to evoke the 2nd person face of God, to being vessels of emergence for the new thing Spirit is doing.
ReplyDeleteI imagine an evolutionary Pentecost, not unlike the first Pentecost that gave birth to the church. This outpouring of Spirit that comes with adopting an evolutionary spirituality, will not only breathe new life into the church, but will also activate the world’s two billion Christians to join forces across denominations, with other faith groups and with non-faith communities, in a transcendent project to consciously collude in birthing a new species of human, fit for the complexities of 21st life on our beloved planet."
TUAD asks:
ReplyDelete---
Are you actively trying to ruin "Evolutionary Christian Spirituality" with blog posts such as these?
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Nope. I'm not "actively" trying to do anything to a fringe group I never heard of before you brought them up :-)
Thanks for that post, Pete. You present an interesting comparison between those two lines of evidence that I never thought of before.
ReplyDeleteI've noticed that adherence to common descent can create problems for evolutionists - except in their own minds. Thinking that common morphology implies common descent is one thing, but the common descent goes back to the unprovable Darwinist presupposition that the first life on earth came from a single cell. For example, what morphology could possibly imply that a whale and a tree have some common ancestry? If they say that the commonality is that both life forms have a genetic code, then they still must explain why that genetic code couldn't have occurred independently. Therefore, the whole common descent argument begs the question that the genesis of the first self-reproducing cell was exceptionally improbable to begin with.
ReplyDeleteOn another note, this is related to Steve's recent post Deception and Healing in that as common morphology implies a common cause, that cause is not necessarily naturalistic, but that evidence like this begs the question of a common designer and actually serves as an evidential revelation of God's creativity.