I have encountered this phrase as an argument against evolution. People who are skeptical of or plain don't believe in evolution say this in a derogatory tone, as though because evolution is a theory, it doesn't hold that much validity.
These people are actually both wrong and right. They are right in the sense that evolution IS just a theory. However, what is not understood is the concept of theory in science. In scientific usage, the term "theory" represents a concept or model that is so well tested that it is effectively a fact. The only caveat to this is that you can never prove anything to be absolutely true. I will go into this in a subsequent post because I feel it would take me too far from my point here. But the bottom line is that in science, theory = extremely extremely extremely well tested concept, which may as well be a fact.
An excellent counter-phrase to the title of this post is "gravity is just a theory". In scientific terms, gravity IS just a theory. It cannot be proved to be absolutely true, but every single test that has ever been done shows the same result - gravity pulls things together! This is the power of a theory in scientific terms. And I sincerely hope those reading this realize that gravity does work all of the time...
The ambiguity comes into play when one considers the colloquial use of the word theory. Many times, maybe on TV, you'll hear things like "theoretically, that's possible", or "I have a theory as to why...". This is actually the wrong usage of the word, and it should be replaced with hypothesis or hypothetically. But nonetheless, it has slipped into colloquial use as meaning something that is not well-supported or is just a guess that may or may not be true.
When scientists refer to the theory of evolution, evolution is given the same status as gravity in the theory of gravity. Evolution has passed many many many tests, and we have actually seen animals develop mutations (an integral component to the theory of evolution). So, the evidence for evolution is overwhelming.
Sorry young-Earth creationists, or any other deniers of evolution - you are JUST as wrong as those who still think the world is flat (yes, these people exist). I am pretty sure you aren't going to leap into the air, hoping to fly under the idea that "gravity is just a theory".
|says jumping cat... right before he falls back down|