A wonderful example that illustrates this point is given by biologist Steve Jones, as recounted in his book
Almost Like a Whale: The Origin of Species Updated (1999) (Chapter IV, Natural Selection). (Thanks to
Heidi Cool for alerting me to the
podcast of a talk by Jones which is where I first heard this story.)
I once worked for a year or so, for what seemed good reasons at the time, as a fitter's mate in a soap factory on the Wirral Peninsula, Liverpool's Left Bank. It was a formative episode, and was also, by chance, my first exposure to the theory of evolution.
To make soap powder, a liquid is blown through a nozzle. As it streams out, the pressure drops and a cloud of particles forms. These fall into a tank and after some clandestine coloration and perfumery are packaged and sold. In my day, thirty years ago, the spray came through a simple pipe that narrowed from one end to the other. It did its job quite well, but had problems with changes in the size of the grains, liquid spilling through or − worst of all − blockages in the tube.
Those problems have been solved. The success is in the nozzle. What used to be a simple pipe has become an intricate duct, longer than before, with many constrictions and chambers. The liquid follows a complex path before it sprays from the hole. Each type of powder has its own nozzle design, which does the job with great efficiency.
What caused such progress? Soap companies hire plenty of scientists, who have long studied what happens when a liquid sprays out to become a powder. The problem is too hard to allow even the finest engineers to do what enjoy the most, to explore the question with mathematics and design the best solution. Because that failed, they tried another approach. It was the key to evolution, design without a designer: the preservation of favourable variations and the rejection of those injurious. It was, in other words, natural selection.
The engineers used the idea that moulds life itself: descent with modification. Take a nozzle that works quite well and make copies, each changed at random. Test them for how well they make powder. Then, impose a struggle for existence by insisting that not all can survive. Many of the altered devices are no better (or worse) than the parental form. They are discarded, but the few able to do a superior job are allowed to reproduce and are copied − but again not perfectly. As generations pass there emerges, as if by magic, a new and efficient pipe of complex and unexpected shape.
Natural selection is a machine that makes almost impossible things.
In other words, by
mindlessly applying an algorithm based on the principle of natural selection, they were able to come up with a complex design for a superior spray nozzle that was inconceivable to the scientists trying to design one using engineering and science principles.
Believers in a god-like designer might argue that what natural selection did here was outperform mere mortal designers and that god, being a perfect designer, would be able to come up with a better design. But that argument doesn't work that well, either, as I will discuss in the next posting in this series.