What if the Nazis had won; Newton had abandoned science; electric motors had pre-dated steam engines; Darwin had not sailed on the Beagle; Charles II had no interest in science and a young Einstein had been ignored?
EIGHTEENTH-CENTURY scientists thought of electricity and magnetism as substances, “imponderable fluids” whose particles were too small and subtle to be detected by ordinary instruments. In their eyes the two fluids were utterly separate and distinct. It was no more possible to transform electricity into magnetism than turn water into wine (without divine assistance, anyway).
English chemist and physicist Michael Faraday saw it differently. Early in the 1820s, Hans Christian Ørsted and André-Marie Ampère had shown that an electric current moving through a wire generated a magnetic field around the wire. Building on their work, Faraday showed in 1831 that the reverse was also true: moving a wire through a magnetic field creates an electric current in the wire. It was Faraday who drew the revolutionary conclusion that electricity and magnetism were two manifestations of a single phenomenon, and it was also Faraday who recognised the technological implications. The use of an electric current to generate a magnetic field became the basis of the electric motor, and the use of magnetic fields to create an electric current became the basis of the electric generator.
Faraday’s conceptual breakthrough happened when it did for identifiable reasons. One was the invention of the battery, which could provide a steady flow of electricity. Another was the Romantic movement, which promoted a holistic view of the world that encouraged scientists to consider that seemingly discrete phenomena might be connected. Suppose, however, that ...