|Written by Guy Skeptic|
|Monday, 05 January 2009 10:47|
One of the common tactics of evolution deniers is to assert the perfection of the human being or the perfection of the planet itself. It is easy, however, to show that the human body is not perfect. There are numerous examples in our anatomy or physiology and pointing these out is not the goal of this essay. Rather, I wish to present the idea that in nature, perfection is an almost meaningless concept. This has general implications extending beyond debates about evolution. Many of the ideas in this essay were inspired by Richard Dawkins' The Selfish Gene and I advise the reader to use that as a reference.
Imagine that you are a one-celled, asexually reproducing organism. One day you might decide, so to speak, that it's time to start a family. So, in the manner of one-celled, asexually reproducing organism, you copy all your DNA and split apart. Now imagine that you can do this perfectly. After a while you've got many exact clones of yourself floating around. Then imagine that the seasons change and the puddle you are swimming in is too warm for you to survive. How many of your offspring make it out alive to tell future generations of the great warm spell of 2008? None of them. They all die because they are all exactly the same.
But what if you don't copy yourself exactly every time? What if once in a while, there's a screw up? Now in this puddle, some of your kids are not exact clones of you at all. Some of them are different, and when the great warming of '08 happens, by some chance a number of your offspring have DNA that helps them cope with the environmental change. In this case, some of your children survive to witness the day that a salty rock falls into your puddle. The salinity of the puddle becomes too high, and once again everyone dies.
Now consider our own species, the human being. We are omnivores and can digest plants as well as meat. This means that in ancient times before supermarkets, if the hunt went badly, we could still eat plants and survive. However, the plant diet isn't perfect. It is difficult to get all 21 essential amino acids from plants alone. Likewise, it is difficult to get all needed fiber need from a diet of pure meat. We see that neither of these abilities is as well developed as in animals that are pure carnivores or herbivores. We trade off the ability to process plant proteins in order to gain the advantages of an omnivore.
What do these examples have in common? In each case, we see that being perfect ultimately fails. Perfectly replicating your DNA, or perfectly being able to digest meat, will result in nonsurvival. In other words, perfect systems fail when circumstances change. As a consequence, nature tends to work by hedging bets. Therefore, animals are not perfectly adapted for any situation. A better term might be optimally adapted. We all have variables in our physiology that can be altered to some degree to fit a certain situation. What we can do is alter these values and try to find the maximal combination for any situation.
Now you might be thinking, AHA, I got you. The perfect case is to be prepared for any situation. This sounds good at first, but inevitably it is impractical for two reasons. One, it is impossible to anticipate every possible outcome. Two, it is impossible to store all the supplies needed for all possible situations. You have to choose a few parameters that you think are the most useful and optimize those the best you can.
The lack of a consistent definition of perfection in nature is actually more of an argument for evolution than against it. After all, the object of evolution is survival, not perfection. In a broader sense, though, the deficiency of perfection is also true for life. In the most direct sense, we can never prepare fully for every emergency nor is it a good idea to only prepare completely for just one. But in a more general sense, we can see that it is a waste of time searching for the perfect school, apartment, partner etc. because perfection does not exist. But it is also important to remember that circumstances are always fluid, and that perfection fails when circumstances change.
Even if you could find that perfect thing, the imperfect but optimal thing would still be the better choice.