Confirmation Holism - Undetermination in Physical Theory

Undetermination in Physical Theory

By 1845 astronomers found that the orbit of planet Uranus around the Sun departed from expectations. Not concluding that Newton's law of universal gravitation was flawed, however, astronomers John Couch Adams as well as Urbain Le Verrier independently predicted a new planet, calculated its weight and orbit through Newton's theory, and so was discovered the planet Neptune where predicted. And yet neither did this empirical success of Newton's theory verify Newton's theory.

Le Verrier soon reported that Mercury's perihelion—the peak of its orbital ellipse nearest to the Sun—advanced each time Mercury completed an orbit, a phenomenon not predicted by Newton's theory, which astrophysicists were so confident in that they predicted a new planet, named Vulcan. In 1905, however, Einstein's special theory of relativity claimed that space and time are both relative, refuting the very framework of Newton's theory that claimed that space and time were both absolute.

In 1915, Einstein's general theory of relativity newly explained gravitation while precisely predicting Mercury's orbit. In 1919, astrophysicist Arthur Eddington led an expedition to test Einstein's prediction of the Sun's mass reshaping spacetime in its vicinity. The Royal Society announced confirmation—accepted by physicists as the fall of Newton's theory. Yet few theoretical physicists believe general relativity a fundamentally accurate description of gravitation, and instead seek a theory of quantum gravity.