"Just a Theory"

I don't like taking sides in debates about religion, but when it comes to whether or not we should teach both evolution and creationism in biology classrooms, there's a certain phrase that gets thrown around which I think is being used very incorrectly.

A major section of the debate revolves around those on the side of creationism mentioning that evolution is simply a theory while those on the side of evolution retort that it has been established as a fact. Both of these arguments are founded upon a misunderstanding of science and the scientific method: what it means for science to be “right” or “wrong.” A hypothesis is an initial guess which a scientist has taken in an attempt to explain some observed phenomena. Many mistake a theory to be the same as a hypothesis, when instead a theory is a hypothesis whose predictions have matched experimental observations and continue to do so. In this sense, a theory is not necessarily an established fact but it does hold the condition that it has yet to be proven false. The only way a theory can be proven absolutely true is if has withstood, does withstand, and will continue to withstand all experimental attempts to disprove it. Since this is clearly impossible as it would take an infinite amount of time to confirm, a “good” theory is simply one which has survived a great number of attempts to disprove it.

At the same time, EVERY theory carries with it a scope of accuracy, essentially stating that the theory may not be all-encompassing but that there do exist particular scenarios in which the theory remains valid. Like I talked about in an earlier post, Isaac Newton’s theory of gravity is an example of such a case. Not long after Newton published his theory of universal gravitation, it was demonstrated via extremely accurate measurements that the orbit of Mercury deviates slightly from that predicted by his law. Physicists searched for disturbances which might have led to the deviation, such as large clusters of asteroids or clouds of dust which might have been distorting Mercury’s orbit. Ultimately, nothing was ever found which was substantial enough to account for the discrepancy, and the anomalous orbit of Mercury was one of the first confirming pieces of evidence which allowed Einstein’s theory of General Relativity to replace Newton’s theory as the most accurate description of gravity because it was able to give the correct orbit. Even so, Newton’s theory is still taught to students at both the high school and university levels because its description of gravity is still sufficient in all but the most extreme cases.