> "Be skeptical. But when you get proof, accept proof." A useful article, but one that perpetuates a myth about science -- that theories are eventually either

> "Be skeptical. But when you get proof, accept proof." A useful article, but one that perpetuates a myth about science -- that theories are eventually either conclusively proven or disproven, as they are in mathematics. In science, because its theories are about reality, theories can be conclusively disproven (falsified), but they cannot ever be proven true once and for all. Instead, they remain potentially falsifiable by new evidence. Philosopher David Hume aptly summarized this precept by saying, "No amount of observations of white swans can allow the inference that all swans are white, but the observation of a single black swan is sufficient to refute that conclusion." I say this because any number of times in the history of science, an established theory, one that people believed to be beyond question, was replaced by a better theory, one that explained more with fewer axioms, or that addressed new observations that invalidated the original theory. Examples include: * The Ptolemaic solar system theory that asserted that the earth was motionless at the center of the solar system, orbited by the sun and planets. This theory was replaced about the time of Galileo by the heliocentric theory. * The idea that disease was caused by bad air, an idea from which we get the words "miasma" and "malaria". This theory was eventually replaced by the germ theory. * The Phlogiston theory. Phlogiston was believed to be a flammable essence that was consumed or "dephlogisticated" when things burned. We now know that combustion is caused by high temperature and a mixture of fuel and oxidizer, and there is no phlogiston. * The ether theory, the idea that light waves propagated through a luminiferous ether, not unlike water waves in water. This idea was replaced by relativity theory, which does away with the need for a propagation medium for light. Many scientific theories are well-supported and very likely to be true, but none of them ever becomes absolutely true, beyond refutation. This perpetual falsifiability idea separates empirical science from mathematics. In mathematics, once formally proven, an idea is placed beyond refutation. In science, this is never true.