Bill Maher has been having a ball posting clips of Tea Party favorite, Delaware Republican Senate candidate, and Sarah Palin endorsee Christine O'Donnell from when she (for reasons I don't understand) appeared on several episodes of Maher's show POLITICALLY INCORRECT in the late 1990s.
In one of the more recently released clips, O'Donnell lets this one loose:
O'DONNELL: You know what, evolution is a myth. And even Darwin himself -
MAHER: Evolution is a myth? Have you ever looked at a monkey?
O'DONNELL: Well then, why they -- why aren't monkeys still evolving into humans?
O'Donnell is flat wrong about evolution being a "myth" and Maher's comeback, while funny, made no traction. Let me trot out my standard stump speech on the subject.
Yes, "evolution," or as it is more formally known, "natural selection," is indeed a theory. Instead of blathering on about the dictionary definition of the word "theory" or more pertinently what the term means as it's applied in the sciences, it may be more useful for me to point out that evolution is a theory the same way gravitation is a theory. Or the Standard Model of particle physics. But just as the theory of gravitation was set forth over 400 years ago and has held up sufficiently to enable us to land manned spacecraft on the Moon, deduce the existence and location of Neptune before it was ever observed, and sling spacecraft from here to Venus twice and back to Earth once on its way to Jupiter and Saturn with freakish precision, the theory of evolution was coarsely set forth over 150 years ago and has been verified and refined by experimental and emprical means ever since, and the molecular mechanisms by which evolutionary processes function have been understood and described for over 50 years. Evolution lies at the heart of all the life sciences and underpins a huge array of other theories in molecular biology, paleontology, anthropology, and medicine. Were evolution merely a myth, whole swaths of mankind's understanding of itself and all life on Earth would fly apart like a Jenga game given a swift kick.
The thing about "theories" in this context is that when they hold up time and time again when put to the test, and other theories that interlock with those theories also hold up when tested, a web of confidence hardens around them; they become reliable. We know the Standard Model works because cell phones and nuclear reactors work. We know the theory of gravitation works because we can soft-land spacecraft down on other planets with regularity. Evolution is harder to test because among macroscopic living things, evolutionary processes take many, many generations to play out and because the processes are not simple or straightforward. But biologists working with microorganisms with very fast replication cycles can observe it, and even when armies of little motorized machines are imagined computationally with their components arranged at random, judged by computer on their ability to locomote on a flat surface, and made to "mate" and "reproduce" in a biology-like manner, their "offspring" become very efficient walkers after a surprisingly small number of generations. And we know evolution works because we can keep making flu vaccines work (even producing a new vaccine specifically for a novel substrain of influenza virus in a matter of months) and also because we can disassemble and analyze creatures' DNA and trace their ancestry back to antiquity.
So concludes my stump speech.
All of these theories have been subject to refinement and extension as new observations arrived. Isaac Newton's predictions about gravity were not sufficient to precisely describe Mercury's orbit around the Sun; because that planet is so close to the Sun and the Sun is so massive, effects predicted by Albert Einstein's theory of special relativity become significant; time itself goes a tiny but measurable bit slower on Mercury relative to us on Earth because of its proximity to the Sun. Similarly, Darwin - who was a naturalist, not an experimental research scientist, after all - set forth rather vague notions of how evolutionary effects play out in nature without benefit of understanding any of the underlying mechanisms (that came about a century later). Subsequently, in the 20th century, refinements like Stephen Jay Gould's "punctuated equilibrium" idea came closer to explaining what scientists observe in nature. Had Darwin followed his thoughts to their logical conclusion, one species of plant or animal would be nothing but a point on a smoothly shifting transition between two other points on the same transition - that's not what we see; Gould's refinement does a much better job of describing nature but is more complex than Darwin's original postulation.
Which brings me to Christine O'Donnell's question, which on its face, is actually a reasonable one: why aren't monkeys still evolving into humans? One problem with her question is that its premise is badly flawed. I'm going to give her the benefit of the doubt that when she says "monkeys" she's referring to not just true monkeys but also many apes; this is a common misconception that, in this case, actually helps O'Donnell's case because it's the so-called great apes - especially orangutans and chimpanzees - that are our closest genetic relatives. But the real point is that the ancestors of those species and ours, going back to the ancestors all three or any two have in common, are long extinct. So it's not reasonable to consider one species evolving into any other species that's a contemporary to it; any two contemporary species of animal will have a common ancestor that necessarily predates them both, and both species are on their own evolutionary paths that will lead to either extinction or yet another species.
I should also clarify that "evolving" isn't the same thing as "speciating," which is when one species separates into two or more. When O'Donnell speaks of Species A "evolving" into Species B, what she seems to really mean is "speciating."
Aside from its flawed premise, O'Donnell's question shows more than anything else an ignorance of the time scales involved in the evolution of macroscopic life on Earth. Humans that look like us are about 200,000 years along, down a line that split off from chimps about 4.1 million years ago (as a species chimps are very old compared to humans, which has a lot to do with why chimps pretty much all look the same; leave Earth and come back in a couple million years and humans - if we still exist - will pretty much all look the same too). An animal like the platypus, which goes so far back that something visibly recognizable as platypus-like was contemporary with dinosaurs, dates to somewhere between 19 million and 48 million years ago (meaning that if you went back in time 10 million years, a platypus would pretty much still be a platypus!). So right off the bat, you can see that people live nowhere near long enough to see big animals speciate in the way O'Donnell's question suggests.
Christine O'Donnell did not come out with this declaration about evolution when she was some uneducated teenager; rather, it happened when she was an uneducated adult, as she appears to remain today. But beyond any mere passing incomprehension of a fairly significant concept like evolution, O'Donnell appears to reside in a world where things that would traditionally grace the cover of the WEEKLY WORLD NEWS - alongside Bat Boy and the meddlings of the alien P'Lod in our government's affairs - are somehow real. Witness this bombshell she dropped on Bill O'Reilly in 2007: "American scientific companies are cross-breeding humans and animals and coming up with mice with fully functioning human brains!"
Quite simply, a creationist or someone who thinks that the things that mad-scientist characters do in cartoons are real has every right to live and be that way - but they disqualify themselves from public office. To extend the above analogy, a creationist is akin to someone who claims that every so often, water will flow uphill or that a hammer may hover in place when you release your grip on it. Such a demonstrable and willful lack of understanding of the natural world calls into question any understanding they would have of the economic, political, technological, legal, and sociological worlds; I contend that a facility in those arenas - or, at bare minimum, the the facility to acquire the knowledge as called upon - is a prerequisite for elected officials. Her endorsees and her ardent supporters do not hold this view. It is vitally important that they be counteracted and outnumbered at the polls.