It's a common belief that Thomas Edison invented the light bulb. It's a bit wrong, but at least it's common, unlike the belief that Thomas Edison invented the rotary book, which made it impossible for people to whom you had loaned books to crack the spine open, by making your books prone to rolling away unattended. And yet what would be the point of light bulbs if there were no way to turn them on and off? There's pride of ownership, certainly, but one can take pride in owning many things regardless of whether they are light bulbs. Heavy bulbs, for example, can bring at least as much pride, not to mention financial success next time you visit Holland of 1636.
One famous dictate of engineering design is that a new invention works, initially, very much like the thing it's meant to replace. Thus, as they replaced horse-drawn carriages, early locomotives were harnessed with bridle and saddle and steered by a complex system of reins. This lasted for minutes, until the reins were broken by outcroppings of metal we may as well call flanges and the saddle grew hot as the steam boilers, resulting in over forty-six previously unplanned but very specific words being said about the railroad company president. But the intention was there.
And so with light bulbs initially seen as ways to replace candles and gas lights, the obvious way to turn them on is for a person to strike a match, then to strike it again, and then to turn it over and strike it again, and then to try the match on its side, so on the last chance it finally catches fire; then, the person holds the burning match against the light bulb until something happens, for example having the match go out, the bulb break, or the fingers of the person holding all this getting burned. This produces little light and much frustration, which is to be expected among early adaptors. In any case sales of replacement matches, bulbs, and fingers were brisk, and sales clerks were not prone to taking customer remarks personally.
With matches a proven fiasco, what was to be done? We can find inspiration from the idea that of electricity as a liquid, much like soda, rather than a set of solid objects, such as drink coasters. Obviously there's nothing to be done if a stream of drink coasters is coming at you, at least once the coffee table and end tables are filled, but you can do something about liquids. And thus we have the electrical cork: simply jam a small fustrum, if that is the correct word (it is not: it should be ``frustum'', but never is), of cork into the wires until the electricity is choked off and the light goes out. Staggering out from the blazing electrical fire we find that the cork model has its flaws: taking the cork out doesn't cause the light to go back on.
Modern light switching implements the control of electrical current in a variety of ways. The most important method is the use of the thyristor. This fascinating solid-state technology connects an N-type semiconductor with the muscles of the upper leg. How this allows for the control of lights, particularly if a person is nowhere near the room, remains a mystery. Luck must play into it since the current (and the modern) system seems to work. Still, this might explain all those people who wander around with their toes blinking on and off. Nothing will explain the people who leave on the high-beams of their phalanges all day.
What of light switching in the future? The most obvious trend is for the natural fears of ``burn-in'' where a fixed image gets imprinted onto the light bulb, making an unavoidable part of its appearance forever, to result in the adaptation of screen-saver technologies to light. In this way, a light left on for, say (or pantomime), twenty minutes will automatically switch to a lower-power version of lighting, with the casting of pleasant images. This should give people something impossible to resist to watch, and should cure society of its productivity.
Trivia: The initial publicly announced plans for the Chrysler Building were released 7 March 1929. Source: Higher: A Historic Race to the Sky and the Making of a City, Neal Bascomb.
Currently Reading: And Four To Go, Rex Stout.