We’ve discussed what scientists mean when they speak of a theory. By knowing the proper definition of a scientific theory, we can now easily see that using the dismissive phrase, “x isn’t true because it’s just a theory” as an argument against “x” doesn’t make sense anymore.
The mistake gets made because theory in common conversational English means nothing more than an assumption or an idea. Not only that, often it denotes something that doesn’t work in practice! For example, someone in an office environment might say that, “If I run the numbers this way, in theory we should always get this result, but that’s rarely what happens.”
So now we are suggesting that theory doesn’t represent reality; which is almost the opposite of theory in science!