Most people do not know the difference between a theory and a hypothesis. These two terms hold different connotations and meaning for the public than does for scientists--or at least science trained.
|Page from Charles Darwin's diary|
(courtesy of Darwin Online).
In science, a theory is a well-supported fact. It is supported and corroborated by many tests or experiments and observations. Examples of theories in science include the theory of evolution in Biology, the theory of plate tectonics, theory of gravitation, the theory of Relativity, and the laws of photoelectric effects(which by the way is one of Einstein's greatest contribution to science which gained him the Nobel Prize in theoretical physics in 1921, but I digress). These theories are not conjecture and are considered facts because they have been proven over and over again, consistently, and are in a way, predictable. No serious person, in my opinion, doubts gravity.
A scientific hypothesis is a question or idea that remains to be proven--meaning it is not yet quite a theory or law; more observations and experimentation is needed to corroborate it or disprove it. For example, the hypothesis that dinosaurs were warm-blooded, or whether natural selection is the main mechanisms of speciation--the source or origin of species, or the currently hot hypothesis of human-induced climate change. These are scientific hypotheses.
An important aspect of hypotheses is that they must make testable predictions. If a hypothesis does not make a prediction or gives it certain qualities that allow the researcher to test it, then the hypothesis make the logical fallacy of being empty. An empty hypothesis thus makes no prediction and is untestable. One could never know whether is true or conjecture and would have to speculate always on its foundation. An example of this is that of the Bermuda Triangle, but that's for another post. These are the meaning of a scientific theory and hypothesis as intended.
The public, however, uses the term theory with another meaning. For instance, the theory that Big Foot exists, or the theory of Kennedy's assassination, or even of ancient aliens, gave rise to our most important civilizations. These in reality, if there is any serious intention, are only hypotheses. They still require much more convincing evidence in order to be proven or disproven. But they are by no means theories or laws, they are still hypotheses.
So there, the public confuses the meaning of the terms hypothesis and theory. You may hear it on the news or read it on social media. But these vehicles only seem to obscure and contort the meaning of these two terms, which results in a confused usage by the public, leading to the misusage of the term theory when is really meant hypothesis.
|Famous Charles Darwin "I Think" quote.|
Charles Darwin diary courtesy of Darwin Online.
I recommend, although in my very own biased way, two books that can expand on these topics, and help in our ever-continuous battle against science illiteracy in the World. One is "Unscientific America: How Scientific Illiteracy Threatens our Future" (2010) by Chris Mooney and Sheril Kirshenbaum, Basics Books, New York. The second is Donald Prothero's (2007) "Evolution: What the Fossils Say and Why it Matters" Columbia University Press, New York.