The word theory entered the English language in the late sixteenth century meaning conception, mental scheme, speculation. Arts and sciences began using the word in the seventeenth century but in a different meaning.
Contrary to popular belief, in science, a theory is not the best-educated guess scientists have at the time about a certain natural phenomenon. On the contrary, a scientific theory is a well-confirmed type of explanation of nature, made in a way consistent with modern scientific methods.
A scientific theory is a framework for observations and facts in the natural world, and it does not only address existing scientific data but also makes future predictions. Hence, scientific theories are repeatedly tested and confirmed through experiments or observation.
Following are some examples of scientific theories:
Change in the heritable characteristics of biological populations over successive generations is called evolution.
We know that evolution is a fact thanks to massive evidence from other branches of science such as paleontology, genetics, zoology, and molecular biology. Evolutionary theory merely explains what the mechanics of evolution are, and how it works.
Following are some examples of observable evolution: