Again, perusing posts about computer systems implementation, I come upon the debate between “the right thing” and “worse is better,” I can’t help but think about the way natural selection works.

The reason why I think intelligent-design is dead in the water is because natural selection has engineered things that are clearly not “the right thing” (using the connotation as described in the article I cited—i.e., a definition limited to systems implementation.) The one that comes to mind easiest is the way the human retina is designed. For those who haven’t taken anatomy, the retina is the light-sensing organ that sits in the back of the eye, which basically converts photons into action potentials, that is, electrochemical nerve signals that are the lingua franca of the brain. It works pretty much like how film (or, to be more modern, a CCD) works. But the bizarre thing is that the light-receptive neurons transmit their signals to higher-level neurons that are actually in front of them, meaning that the light-receptive neurons are actually partially obscured by a tangle of neurons. Clearly, a sane engineer would not do this, and, in fact, in other organisms, this is not the case—a more sane design that puts the light receptors in front and the higher-level neurons behind them was implemented instead.

Now, mind you, both implementations do what they’re supposed to do. You and I can still see all right even though we have a “worse-is-better” implementation. And clearly, evolution also demonstrates that this isn’t necessarily the optimal design, because other organisms have the saner “right-thing” implementation. I just can’t wrap my mind around the idea that a sentient being would actually implement sight both ways. But what do I know, maybe God has a sick sense of humor.

But back to “worse is better” and evolution. There are clear reasons why natural selection might favor the easier implementation, the biggest of which is entropy. In the design of organisms, more features does not often give one a selective advantage.

The simplest example is antibiotic resistance. One would think that all bacteria would evolve antibiotic resistance since it would ensure their (individual) prolonged survival. But, thanks to thermodynamics, there is cost for harboring an antibiotic resistance gene. Just by sheer kinetics alone, a bacteria that has such a gene will not replicate as fast as an antibiotic-sensitive species. This fact alone has probably saved us despite our continuous abuse of antibiotics. What probably happens (no one has proved this experimentally) is that the antibiotic-sensitive species simply reproduce quicker and outcompete their antibiotic-resistant brethren for nutrients. Hence, we can live infection-free lives despite constantly using triclosan-containing handwash.

Hence, the reason why some organisms have sane retinas and why we have ass-backward retinas: if we have evolved from older but similar implementations of life, the laws of thermodynamics would favor tinkering with the design instead of completely reinventing it. So maybe somewhere deep in the evolutionary past, some stray cosmic ray reversed the way retinas grew in the eye in some organisms, and since this did not create a significant selective disadvantage, both implementations co-exist.