Evolution Versus Engineering

What's the difference between evolution and engineering? Engineering is the designing of a whole out of parts suited to their individual purposes. Evolution is the process of tiny incremental changes, each making some small or large improvement in the ability of the thing to survive and reproduce. A good engineer avoids the kluge-jargon for the use of a part not particularly suited to its purpose. But evolution favors, even cherishes, the kluge. Suddenly finding a new purpose for a part without significantly diminishing its old function is a staple of the evolutionary process.

A classic example of an evolutionary kluge is the human eye. The nerves that connect the light-sensing cells to the brain actually come out the front of the retina rather than the back-the "wiring" protrudes out into the eye's field of vision. It's difficult to imagine an engineer, let alone God, designing something this way. But evolution took what it had to work with and, kluge by kluge, built an eye. You can imagine a primitive creature having a light-sensing cell that evolved over millions of years into a better and better source of vision. Back when the light-sensing cell was simple, there was no advantage in having it oriented one way or the other. By the time it had developed through kluges into a complex eye, with a focusing lens, there was no way to "redesign" it so the wires would come out the back.

Evolution is all about kludges.