One of the founding principles of science is that the exception tests the rule. So if there is an exception to any rule, and if it can be proven by observation, that rule must be wrong.
For example, Aristotle believed that heavier objects fell faster than light object, and this was the conventional wisdom for many centuries. Then Galileo decided to test it in his famous Leaning Tower of Pisa experiments. It’s not known if he actually dropped cannonballs of different weights from the tower, but he did discover that regardless of the weight of the objects, they fell at the same rate.
So, based on the experimental evidence, Aristotle was wrong—regardless of how great a philosopher he was.
Another example: Isaac Newton was convinced that space was filled with a “luminiferous ether” in which light traveled through. This was disproved by Michelson and Morley in 1887. They were trying to measure an ether wind by comparing the speed of light in perpendicular directions. The theory was that the earth’s movement through space creates an ether wind that would effect the speed of light in the same way that a jet travels faster in a tailwind and slower in a headwind. What they discovered was that light moved at the same speed regardless of direction, and, therefore, Newton had to be wrong. It would not be until 1905 that we would get a new theory explaining light and how it travels by a 26 year old Swiss patent clerk.
1) True or false: Galileo proved that heavier object fell faster than light objects.
2) A luminiferous ether was hypothesized to be __________.
a) a light-emitting organic compound b) the medium through which light travels c) the vacuum of space d) an optical illusion
3) True of false: Michelson and Morley devised an experiment to measure the speed of light.
4) Which of the following is not true:
a) light travels fastest when moving through a vacuum b) light displays wave-like properties c) light is composed of particles d) light moves at the same speed everywhere.
5) A new theory of light was developed in 1905 by ________.