5. Evolutionary Theory
Probably the most controversial entry on this list, evolution inspires more heated debate and animosity between its adherents and detractors than any other scientific theory, but let’s get a couple of points out of the way. Darwin never stated that humans evolved from apes; they both have a common ancestor. Also, ‘On the Origin of Species’ (published in 1859) only mentions human evolution in passing, for two reasons: Darwin was wary of the response (‘Vestiges of Creation’ in 1844 had met with controversy), and there wasn’t enough evidence available at the time to make a detailed analysis of human evolution. That said, Darwin’s book brought about a classic paradigm shift; never again could man look at the natural world around him the same way (or himself, for that matter). As for Darwin, over the years his religious beliefs had eroded. By 1859, Darwin considered all religions equally valid, and was critical of the Biblical account of creation. The death of his daughter Anne in 1851 at age 10 had also contributed to his loss of faith, and he stopped attending church entirely (though he never quite became a total atheist).
4. Quantum Mechanics
Whereas relativity theory (entry 2) was the product of a single mind, the contributors to quantum mechanics read like a physics hall of fame: Rutherford, Bohr, Planck, Schroedinger, Pauli, Heisenberg, Dirac, Feynman, Gell-Mann, to name a few (Einstein also made important early contributions, but grew to dislike quantum mechanic’s bizarre, counter-intuitive nature). Also, it took several decades and many arguments to bring quantum mechanics to fruition. The frontiers of quantum mechanics are still expanding as ever-deeper levels of matter are probed by powerful particle accelerators and powerful minds alike.
3. Relativity Theory
Like Newton before him, Albert Einstein was an outsider. Often bemused and frequently saddened by the human world, he considered the secrets of nature the deepest problems anyone could face. Mostly unconcerned with worldly affairs, Einstein’s genius took science to unparalleled heights. Any one of the three papers he produced in his ‘miracle year’ of 1905 would have won him the Nobel Prize; it turned out to be his work on the photoelectric effect which did so, but it was special relativity (and in 1915 general relativity) which would seal his reputation as the greatest physicist since Newton, and one of the greatest thinkers in history. In order to redefine the nature of matter, gravity, mass, and energy, Einstein had to draw together mathematical subjects such as differential geometry, tensor analysis, and electromagnetic theory (tales of Einstein’s poor skills in mathematics are entirely myth).
2. Philosophiae Naturalis Principia Mathematica
Though he had to share the development of calculus with Leibniz, Newton can claim the theory of gravity for himself, and it is in the ‘Principia’ (published in 1687) that Newton presents the law of universal gravitation. Using classical geometry and the method of ‘fluxions’ and ‘fluents’ (what we today call differential and integral calculus), Newton could account not just for the fall of an apple, but ballistic trajectories, the orbits of moons and planets, and the motions of stars. With ‘Principia’, physics took a mighty leap forward. As the poet Alexander Pope put it ‘Nature and nature’s laws lay hid in night; God said “Let Newton be” and all was light.’
1. Infinitesimal Calculus