Thursday, May 24, 2007

The Blind Watch Maker - chapter 4 continued.

I remember watching a Addams Family episode where Gomez was returning from parachuting. He explained that each time he does this, he snips a little bit out of the parachute so that eventually he will need no parachute at all! The core of chapter 4 is a synthesis of Paley's wonder together with the idea of evolution. What holds it together is the Gomez logic: We can imagine a small change. The cumulative effect of the small changes allows for big change. It is something that we instinctively know to be false, but virtually impossible to prove false. Just because I can walk increasingly large distances from my home near San Francisco, I really have no expectation of being able to walk to Australia. I can jump a millimeter high one day, and a centimeter the next. Does this mean that I can jump over the moon if I keep at it?

These days, complex systems are never designed from scratch. My several hundred thousand lines of software morphs from one state to another driven both by intelligent design and evolution. When my customers come to me and ask what is possible, there is usually two initial expectations. One is that the effort is incredibly difficult, but usually with a belief that it is much easier than it really is. The other is the opposite of the first. An experienced cost estimator for software or some other engineering project must then visualize an evolutionary sequence that produces the required design. This cost estimator's estimate is invariably quite different from the initial expectations of the customer, unless the customer is also quite familiar with the project. Negotiations are done to bring expectations, costs and risks into some kind of balance. Once the estimate is put into practice, the budget is invariably blown and schedules slip. What was visualized is invariably vastly more difficult when put into practice, no matter what the experience of the cost estimator. Portions of this topic are discussed in The Mythical Man Month by Brooks.

Once the project is finally completed, however, it suddenly seems trivial again. All of the design dilemmas are forgotten and the design increments that produced the final result are trivial to visualize. Suddenly it seems unfair that the costs included dead end design variations and mistakes that needed correction. Again, I am giving all of this in the context of Intelligent Design realities that I live. Not Ivory Tower speculations. There is a huge difference between visualization (imagination) and reality. Yes, Dawkins can visualize all kinds of things, but the gap between imagination and reality is mind boggling.

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