Saturday, June 01, 2013

Adam, Eve, and chimpanzees

Recently, an increasing number of professing believers has decided to jettison the historical Adam. The clincher has been the degree of similarity between humans and chimpanzees.

Now, the specific comparisons have been challenged by Intelligent-design theorists. However, it’s still the case that humans are more like chimps than salamanders.

According to evolution, we account for the similarity based on common ancestry. As a rule, similarity reflects affinity. Degrees of similarity mirror degrees of kinship. Organisms that are more alike are more closely related while organisms that are less alike are more distantly related. By “related,” I mean in terms of common ancestry.

Is there an alternative explanation consistent with special creation? Take the principle of plenitude. According to Christian thinkers like Leibniz, Aquinas, and Augustine, God made a world with maximal diversity. God made a world which would combine as many variations as possible.

(In addition, Aquinas thinks organisms have a hierarchical arrangement–from highest to lowest.)

Although that’s theological, there are secular versions of the principle, viz. the multiverse and the modal realism of David Lewis.

And on the face of it, the natural world does look like just about every conceivable strategy is represented. So this isn’t just an abstract postulate.

Now, assuming that organisms range along a continuum (i.e. degrees of similarity or dissimilarity), it’s inevitable that humans will be more like some animals, and less like others. And if that’s the case, then there may well be one animal that humans are more like than other animals.

That isn’t due to common ancestry, but graded diversity. If God made a full-spectrum world, then humans will resemble some creatures more than others–for the world was designed to exhibit a wide range of biological similarities and dissimilarities. Every feasible or compossible permutation will be represented.

Incidentally, when I speak of a scale (spectrum, continuum) of diversity, I don’t mean that in strictly linear terms. That’s an incidental connotation of the spatial metaphors. I don’t think all organisms can be arranged according to a single principle of continuity and discontinuity. In comparing two organisms, they may be alike in one or more respects, but unalike in other respects. My argument doesn’t require linearity.

To take a comparison, consider all the different styles of chess sets. Some chess sets are more alike, while others are less alike. That’s because humans value artistic diversity. And the world we inhabit seems to reflect God’s artistic diversity.

Another example is musical variation. Classical composers would demonstrate their ingenuity by ringing the changes on a particular theme. Notable examples include Pachelbel’s Canon, Handel’s The Harmonious Blacksmith, Bach’s Goldberg Variations, Beethoven’s Diabelli Variations, Brahms’s Variations on a Theme by Haydn, and Vaughan Williams’ Fantasia on a Theme by Thomas Tallis.

I’m reminded of Paul’s statement about “the plan of the mystery hidden for ages in God who created all things, so that through the church the manifold wisdom of God might now be made known…” (Eph 3:9-10).

As Hoehner says, this carries the connotation of “most varied.”

This is not an ad hoc alternative. It’s a comprehensive explanation, based on one overarching principle. That’s economical. It antedates the creation/evolution debate, so it’s not a stopgap that was pressed into service to stave off the Darwinians. And there’s no presumption that God wouldn’t, shouldn’t, or didn’t design a world with maximal variation.

The explanatory power of false theories

Many professing believers are currently bailing on the historicity of Adam. Indeed, this has become a theological fad. To be an evangelical who denies the historicity of Adam is hip and chic.

The argument that cinches the deal for these people is comparative genomics, viz. genetic commonalities between humans and chimpanzees.

I get the impression that many of these breathless converts to evolution haven’t bothered to study the counterarguments. They discount the counterarguments in advance as the work of “creationists.” Such counterarguments are unworthy of their consideration because they are tainted by the source.

However, I’d like to make a different point. For the sake of argument, let’s grant scientific realism. There are true and false scientific theories.

False theories can have explanatory power. The history of science is chock-full of false theories that explain some of the evidence. I think that’s the case for just about any field of science. Especially in the early stages of scientific investigation, it’s not uncommon to have multiple, competing theories of a given phenomenon. Each rival theory explains some of the evidence.

The challenge is to come up with a theory that explains all of the evidence. And that’s more challenging the more evidence you have to explain. I assume it’s easier to explain the cause of melanoma than it is to explain the origin and diversification of life on earth.

Suppose evolution could explain the commonalities between humans and chimps. Problem is, that’s only impressive if you bracket the selective phenomena for which evolution offers plausible explanations from everything that a theory of origins and biodiversity must be able to explain. Remember, false theories can explain some of the evidence. But that’s a specious explanation, for you have to evaluate a theory by the totality of its explanatory power, or lack thereof.

Evolutionary theory suffers from serious and persistent internal problems. And it isn’t just critics of evolution who point that out. Not just hostile outsiders. It includes scientists who think evolution must be true, that something like the evolutionary narrative had to happen, yet they don’t think the current synthesis can get the job done. Among the older generation, that includes the late Fred Hoyle and Francis Crick.

More recently, the late Stephen Jay Gould was savagely attacked because he made too many concessions to the dreaded creationists. His version of evolutionary theory wasn’t pure enough.

Currently, you have dissenters like Jerry Fodor, James Shapiro, Stuart Newman, Thomas Nagel, and Richard Sternberg, &c.  This has alarmed the gatekeepers of Darwinian orthodoxy, like Jerry Coyne.

The State of the Union