Tuesday, November 24, 2009

Happy Birthday, "Species!"

(From Wikipedia; full-size here)

Today is the 150th anniversary of the first publication of Charles Darwin's masterpiece, "On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life." According to Wikipedia, the title was shortened to "The Origin of Species" in the sixth edition. I hadn't realized that, and had been under the impression that the formal title remained the longer version. Nevertheless, this is probably the seminal work of science ever written. I know Newton worshipers will disagree, and that's fine. But Darwin's approach to gathering broad evidence regarding a seemingly intractable problem- How can we explain the diversity of living things without supernatural intervention?- formulating a hypothesis, then rigorously testing it and gathering more data, and finally offering a thoroughly logical exposition and defense of his theory, more closely models most of modern science than does trying to fit phenomena to mathematical models. This is not to say that scientists don't try to accomplish the latter, nor that the latter is unimportant or trivial. It is merely to say that a "Darwinian approach," so to speak, is more typical than a "Newtonian approach." We try to describe (and circumscribe) a problem, and come up with a logical explanation without reference to actions and processes beyond our ken.

This is the fundamental basis of science: to explain the world around us in terms we are capable of understanding. And with all due respect to the vociferous "New Atheists," that does not necessarily mean we "know" everything, or anything, for that matter. Nor does it "prove" the nonexsistence of a deity. It simply means that we are capable of achieving internally consistent explanations that are not, importantly, inconsistent with other, external, observations and explanations.

Why is this important? Because science, more than any other broad discipline, has shown itself capable of making accurate, (mostly) dependable predictions. Look around where you're sitting and reading this post right now. Can you pick out a single thing in your vicinity that is not where it is, or even exists, because of human predictions? Go ahead, look around... I predict these words will still be here when you look back. I can't spot anything, with perhaps the exception of the fallen leaves across the street, though the trees from which they fell were clearly chosen and planted in the spots where they grow. And most grade schoolers could predict the existence of fallen leaves at this time of year as a result of planting those trees.

Science can range from the astonishingly simple, as the previous example, to the astonishingly elegant (elegance = simple but powerful) as with Darwin's theory, to the astonishingly complex, as with the Large Hadron Collider. (first collisions yesterday!) One of the things that makes me very uneasy about our culture is the way people can separate concepts and ideas that are scientific in nature, like "leaves will fall out of the trees in the autumn," from ideas that are a little more complicated (but not much), and call one "common sense," and the other "science."

Darwin's ideas and argument can be boiled down to the following bullets:
  1. Organisms tend to produce more offspring than can possibly survive. A single parent or pair of parents will tend to produce more than one or two offspring, respectively. Thus over generations, the population of that organism would be expected to increase without limit. This concept is referred to as "superfecundity," which, in English, means "over-reproduction"
  2. Resources are materials or environmental aspects needed for survival, which are, at least in principle, potentially limited. Since, in principal, nothing is infinite, anything required for survival or reproduction- living space, water, appropriate food, shelter, mates, anything- is potentially limited.
  3. Combining points 1 and 2, successive generations of offspring will be set in competition with each other, as their numbers increase, with proportionally more and more limited resources. Some won't survive to reproduce.
  4. Offspring tend to resemble their parents...
  5. ...but with variations. Offspring (at least of sexually reproducing organisms) are not carbon copies of their parents.
  6. Offspring with variations that benefit them in their competition for survival in the environment where and when they live are more likely to survive and reproduce. Offspring with variations that interfere with their ability to survive and reproduce in their environment are less likely to survive and reproduce.
  7. Over many generations, offspring with beneficial variations will more often reproduce offspring with those variations, and those characteristics will become dominant in the species; detrimental variations will, again, over generations, be eliminated.
I'm not sure whether to put the conclusion as a final bullet, but it should be obvious: this process is continuous, and given the amount of time Darwin believed to be available (incidentally, much less than we currently believe to have been available), would lead to the creation of progeny, many generations later, that could be very different from their forebears. So different that would be considered different species; hence "the origin of species."

Points 1, 2, 4 and 5 are simple observations: facts. Points 3, 6 and 7 are, to my mind, unavoidable logical consequences of the other four. Like so many ideas, it seems profoundly obvious in retrospect. But Darwin's ability to synthesize these observations and implications in the context of the mid 1800's is one that we should all respect and attempt to emulate: to find the simple explanation and back it up with so much evidence and data that few who are actually paying attention, or who don't simply dislike the idea and want to be contrary, can argue.

I have read the Origin of Species; my only regret is that I didn't until graduate school. I'm not sure I would have been able to get through the language in high school, but I should have read it as an undergraduate. I wouldn't argue that it should be required for science undergrads, but I don't think any of my profs even recommended it, or assigned passages for reading. And that's a shame. Not only was Darwin a gifted, brilliant scientist, he could write with an eloquence that few can match. For example, this is the final sentence of the first edition of The Origin of Species:
There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

"There is grandeur in this view of life..."

No shit, man, no shit. Words fail me.

But not Darwin.

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