bearing blog: This isn't so hard, folks

Christoph Cardinal Schonborn, archbishop of Vienna, wrote an op-ed in the NYT stating that evolution driven by random processes is incompatible with truth:

Evolution in the sense of common ancestry might be true, but evolution in the neo-Darwinian sense - an unguided, unplanned process of random variation and natural selection - is not. Any system of thought that denies or seeks to explain away the overwhelming evidence for design in biology is ideology, not science.

I would correct the Cardinal on one minor point: an attempt to explain (rather than to explain away) the complete set of evidence technically does count as science. All rational attempts to explain the complete set of physical evidence ---all theorizing---are part of science. Some of it will turn out to be right, and most of it will turn out to be wrong, of course.

And I wonder about this:

In an unfortunate new twist on this old controversy, neo-Darwinists recently have sought to portray our new pope, Benedict XVI, as a satisfied evolutionist. They have quoted a sentence about common ancestry from a 2004 document of the International Theological Commission, pointed out that Benedict was at the time head of the commission, and concluded that the Catholic Church has no problem with the notion of "evolution" as used by mainstream biologists - that is, synonymous with neo-Darwinism.

I'm just wondering which neo-Darwinists he means, and where this quote and conclusion appeared.

Setting that aside, though, nothing the Cardinal has written about the church's teaching is new. You wouldn't know it, though, from reading this analysis piece in the NYT:

LEADING CARDINAL REDEFINES CHURCH'S VIEW ON EVOLUTION

An influential cardinal in the Roman Catholic Church, which has long been regarded as an ally of the theory of evolution, is now suggesting that belief in evolution as accepted by science today may be incompatible with Catholic faith...

Darwinian evolution is the foundation of modern biology. While researchers may debate details of how the mechanism of evolution plays out, there is no credible scientific challenge to the underlying theory.

Assuming (as always) that the evolutionary evidence is responsibly gathered, catalogued, and analyzed, there are exactly two points that the Church makes about it: (1) No theory that excludes the creative action of God can be true. (2) No theory that claims the human soul evolved naturally can be true.

All that is necessary for teachers of evolutionary biology to remain in good graces, so to speak, is to make judicious use of the word "appears," as in "This process appears to be random." Assuming, of course, that this is what the evidence (ahem) appears to support.

That's it.

And then, of course, any evolutionary biologists who think that the sequence of mutations, the changes in environmental pressures, and the probabilities of survival are not random can write, "This process appears to be guided by the following mechanisms..."

Randomness is a tricky thing to determine. Given a sequence of events, what is the probability that it was a random sequence? When I was working on my thesis, I looked at dozens of electron microscope images of close-packed colloidal spheres, and judged whether the packings---all a mix of two different kinds of crystal structures---were likely random stackings or not. I never wrote of any stacking, "This crystal exhibits random stacking." I might have written "This crystal appears to be random stacking." On occasion I would write "This crystal exhibits non-random stacking."

And of course, non-random doesn't mean "this crystal could not have arisen except by the direct action of a designer." It means "some mechanism, some underlying law, caused the particles in this crystal to prefer a particular arrangement."

Here's a quick quiz. I have a quarter before me. Is this sequence of heads and tails random? How could you tell? What does it mean that it isn't?

htht ttttth httthhhhtt

How about this one?

htht hhhtht hthhthhhtt

How about this one?

hthh hthtth tthtttthht

I'll answer below. My point is this: Even with these simple sequences, you cannot know. You can only guess. You know that each sequence, if random, should be roughly half heads and half tails; but you also know that there is no guarantee that a random sequence of only twenty binary choices will divide evenly into half. You intuitively would reject the idea that a recognizable pattern, such as "hthththt..." or "hhhhhhh...." or "hhthhthhthht...." is random; but you also know that these sequences are just as likely as any others of the same length. It has famously been proved that all numbers are interesting; a necessary corollary is that all sequences of twenty binary choices are interesting.

The first sequence (40% h) is random; I flipped the quarter twenty times.

The second sequence (60% h) is designed. Each entry in the sequence is determined by the corresponding letter in my full name: if the letter in my name is from the first thirteen letters of the alphabet, the entry is "h," and otherwise the entry is "t."

The third sequence (50% h) was produced in the following way: I flipped the coin four times to produce the first four entries. Then I put an "h" in the fifth part of the sequence, because I felt like it. Then I flipped the coin fifteen more times to produce the rest of the entries.

Make whatever conclusions you want from this. The cardinal is right: Science can never say with certainty that anything is random---period. Any given scientist can, however, make the claim that something appears random. And other scientists can contradict him or her. And that's okay.