I love sobering thoughts. Here’s one. Around the year 1900, Charles Darwin’s (and AR Wallace’s) theory of variation and selection was virtually forgotten. What is today hailed (rightly) as the greatest intellectual achievement of 19th century science was all but discarded by the beginning of the 20th century.
Why? Because given the world as it was known then, it couldn’t have worked.
I often encounter natural selection described as a beautiful, simple idea. “How could I have been so stupid not to think of it myself,” is the sentiment described. The fact that no one, not Newton, not Descartes, not Aristotle nor Galileo nor Hypatia nor Euclid, thought of it first indicates that it’s not so simple. The fact that the beautiful, simple idea was later discarded is even better evidence.
These days there’s an evangelical named Ray Comfort who is criticizing evolution with what he thinks is a simple, beautiful argument. He’s right; it is simple and beautiful, but also wrong. It is wrong because the facts of the real world take us somewhere else. It is wrong in the same way the rejection of natural selection by 1900 was wrong. It is wrong because it is ignorant of another simple, beautiful idea. Genes are lumpy.
Comfort’s argument goes like this. “Evolutionists” say that elephants evolved from non-elephant ancestors. But the first elephant (for Comfort the first is always a male) had to find a wife. Isn’t it an odd coincidence that just when the male elephant came along, a female elephant evolved, too? But if not, with what creature did the elephant mate?
If you don’t know anything about genetics, this might be a convincing answer. And in fact it was (in different form) the argument that in part caused the rejection of natural selection the first time around.
To choose another example, suppose a white moth were to appear in a population of black moths. That white moth would have to mate with a black moth. If (as was believed at the time) inheritence is blended, their offspring would be grey. These grey moths in turn would overwhelmingly mate with black moths, resulting in even darker offspring, and so on. In this way, any unique traits would disappear almost as soon as they arose.
Ah, but genes don’t blend in this way. Instead, here’s what might happen. A white moth mates with a black moth. Their offspring are ALL BLACK! White has disappeared, not over several generations, but instantly. But isn’t this a backwards step? Patience, grasshopper.
Now the all-black moths mate. Occasionally, two black moths that each have a white parentwill mate. In this cross, one out of four of their offspring will be white! The white trait, hidden in the first generation of offspring, reappears in the second.
If you’ve taken a biology class, you probably recognize this. It’s a common piece of pedagogery, and reveals the pea plant experiments of Gregor Mendel, a contemporary of Darwin whose work was forgotten in his lifetime. Big deal, right?
The big deal (so often missed in introductory material on this subject) is that this discovery, that genes are discrete (I prefer the word “lumpy”), gave natural selection the tool it needed to work! The result is the world you see around you. Because unique traits could survive as discrete lumps of genetic material, even hiding in generations, all manner of variability could eventually appear, spread, and fluorish.
So what does all this have to do with Comfort and his elephants? The point is that Comfort would be right – if inheritance blended. But it doesn’t. Genes are lumpy. An elephant ancestor needn’t be an elephant to carry elephant traits. It can carry genes for elephant-like traits, and those genes can hide within the genome. When those genes come together in the right individual, the traits (completely accidentally) can make that individual more likely to survive, and so the traits are passed on. Eventually, the traits become common in the population, and you have elephants.
The point is not so much that Comfort and the 1900-era biologists were wrong. Being wrong is part of learning. The point is that scientists, by working out sometimes simple, beautiful relationships, such as Gregor Mendel and his peas, can reveal not just a deep truth, but can show us just how and why it is true. This knowledge, gained through long, hard, arduous work, is now available to everybody. You can know things that Aristotle never could have imagined, not because you’re smarter, but because you are alive, here and now, in a world positively brimming with simple, beautiful, and true ideas.
Now that’s a sobering thought.