Effective theory
From Wikipedia, the free encyclopedia
In science, an effective theory is a deliberately limited scientific theory applicable under specific circumstances. In practice, all theories are effective theories, with the name "effective theory" being used to signal that the limitations are built in by design.[1]: 1
An early example[1]: 2 is Galileo Galilei's theory of falling bodies. Using observed values, Galileo deduced that the height of a falling body can be accounted for by constant acceleration, written here in modern notation: where t is the time, z is the vertical position of an object and g is gravitational acceleration near the surface of Earth.
Within the scope of objects falling on Earth, this theory works well. However, as Isaac Newton discovered in his Newton's law of universal gravitation, a more elaborate but still effective theory, has more scope at the expense of additional complications. The next layer was Albert Einstein's general relativity, with more scope but even more complications.[1]: 5