Two thousand years ago, it was thought that the laws of the universe were completely covered by Euclid’s geometry. There was nothing more to be said. This is the illusion of every period. For a long time after Newton’s death, scientists thought that he had said the last word about the laws of nature. Laplace lamented that there was only one universe, and that Newton had had the good fortune to discover all its laws. For two hundred years, Newton’s particle theory of light was generally accepted, as against the theory, advocated by the Dutch physicist Christiaan Huygens (1629-95), that light was a wave. Then the particle theory was negated by the Frenchman, Augustin Jean Fresnel (1788-27), whose wave theory was experimentally confirmed by Jean.BL Foucault (1819-68). Newton had predicted that light, which travels at 186,000 miles per second (around 300,000 km) in empty space, should travel faster in water. The supporters of the wave theory predicted a lower speed, and were shown to be correct.
The great breakthrough for wave theory, however, was accomplished by the outstanding Scottish scientist James Clerk Maxwell, in the latter half of the 19th century. Maxwell based himself in the first instance on the experimental work of Michael Faraday, who discovered electromagnetic induction, and investigated the properties of the magnet, with its two poles, north and south, involving invisible forces stretching to the ends of the earth. Maxwell gave these empirical discoveries a universal form by translating them into mathematics. His work led to the discovery of the field, on which Einstein later based his general theory of relativity. One generation stands on the shoulders of its predecessors, both negating and preserving earlier discoveries, continually deepening them, and giving them a more general form and content.
Seven years after Maxwell’s death, Heinrich Rudolf Hertz (1857-94) first detected the electromagnetic waves predicted by Maxwell. The particle theory, which had held sway ever since Newton, appeared to be annihilated by Maxwell’s electromagnetics. Once again, scientists believed themselves in possession of a theory that could explain everything. There were just a few questions to be cleared up, and we would really know all there was to know about the workings of the universe. Of course, there were a few discrepancies that were troublesome, but they appeared to be small details which could safely be ignored. However, within a few decades, these “minor” discrepancies proved sufficient to overthrow the entire edifice and effect a veritable scientific revolution.