The author seems to say the formula for magic is imagination + determination. Turning on a light would be one kind (or level) of magic: the Harry Potter kind. Inventing light switches, when everybody thinks you have to rub two sticks together, or wire up electrical circuits by hand to get light, would be another. The kind I've seen arguments about recently are analogous to a new kind of light switch, with a built in light sensor, so when you turn on the light it automatically turns it to the "right" brightness for the level of natural light already present. Those against it would maybe rather have a dimmer so they can control the brightness, or maybe rather install the light sensor themselves.