The Science of Discworld IV Judgement Da - By Terry Pratchett, Ian Stewart Page 0,86

the use of plastics to replace metals in the nursery, kitchen and laboratory. Before that, transparent plastics, mostly acrylics, had been used to replace glass in many applications. The progressive use of semiconductor technology is giving us solar panels, tiny refrigerating or heating elements, and a new family of very efficient light bulbs: white-light LEDs. Banks of coloured LEDs can now be tuned to give different lighting conditions; bright white light is not conducive to sleep and can be replaced with softer tones. Flexible television/computer screens, which can be rolled up like paper, already exist in the laboratory, and are not far from commercial production. An entire book has just been encoded in DNA, and a human face has been printed on a human hair.

In biological evolution, it used to be thought that environmental ‘niches’, such as predatory behaviour, were already available and waiting to be occupied, rather as though some cosmic script had already written down all the possible things that an organism might do. Now it is thought that organisms construct niches as they evolve; for instance, you can’t occupy the dog-flea niche until there are dogs.

Even taking copying into account, the analogous questions of competition and niche-construction in technology are as important as they are in the natural world, and they too force the evolution of new products. A good example was the colonisation of the marketplace in the 1970s by VHS videotapes, even though its rival Betamax was much better in several respects. As in natural ecologies, it often happens that a less-adapted, often foreign, invader exploits the ecosystem more effectively, forcing the demise of well-established local species. The grey squirrel, for example, carries a disease that decimates indigenous red squirrels, much as the Spanish invaded South America and destroyed Inca and Maya empires. The red squirrel was better-adapted to its original environment, but the arrival of the invading grey squirrel changed that environment; in particular, it now included grey squirrels and their disease organisms. The change was sudden, biological warfare rather than the usual sedate pace of natural selection in a slowly changing environment.

In the technical world, then, there do exist processes resembling those of organic ecosystems. Many of them are recursive, affecting their own development: supermarkets make their own ecosystem of consumers, just as dogs create a new niche for dog-fleas. This makes questions about the design of technology much more difficult, because there are few real innovations, but many exaptations, copyings and adaptational trajectories. Only a few really novel tricks can be claimed to have a human designer in a non-evolutionary sense.

There is a trajectory of development for a technological product: a car starting from carriages and an engine, steam or internal-combustion; a radio starting from a crystal set and headphones; a bicycle starting as a penny-farthing and evolving through the sit-up-and-beg still seen all over China and India to the mountain bikes and lie-down versions of the latest adaptive radiation.

These are paths through our cultural history, and they make their own contexts as they evolve. The car creates vast and important areas of our cities where cars are built, where auto workers live, where the suppliers of parts have some of their factories and warehouses. When we give little Johnnie a bicycle on his seventh birthday, we introduce him to a new world that has grazed knees, gears, punctures, comparison with Fred’s bike … When the transistor radio erupted into Western culture in the 1960s, it changed the relationships of teenagers to each other and to pop stars, though nothing like as much as the mobile phone has changed all of our lives in the last few years. Alexander Graham Bell, on a promotional tour of his invention the telephone, so impressed one city’s mayor that he is said to have declared: ‘What a wonderful invention; every town should have one.’

Artefacts evolve, and the functions they perform get better, wider, cheaper. But they also change the society around them, so that their ‘improved’ next generation already has the ground prepared for it. The Ford Model T would not have been viable without gas stations, which had appeared to service the much more expensive previous generation of automobiles. In turn, the Model T and other similar affordable automobiles with privacy in the back seat changed much of the sex life of the young men and women who had access to them. Society’s rules change as the Ford Model T, the transistor radio, central heating, subway travel and mobile phones affect their context, and