Christopher Taylor wants to help you avoid mis-using the word “fact” when you’re talking about “theories”:
These days, criticizing or questioning statements on science can get you called an idiot or even a heretic; science has become a matter of religious faith for some. If a scientist said it, they believe it, and that’s that. Yet the very nature about science is not to be an authoritative voice, but a method of inquiry; science is about asking questions and wondering if something is valid and factual, not a system of producing absolute statements of unquestioned truth.
It is true that people need that source of truth and it is true that we’re all inescapably religious creatures, so that will find an outlet somewhere. Science just isn’t the proper outlet for it.
The problem is that there’s no way to test or confirm this theory [plate tectonics]. You can make a model and see it work, you can check out types of rock and examine fault lines, and you can make measurements, but that’s only going to tell you small portions of information in very limited time frames. Because the earth is so huge, and because there are so very many different pressures and influences on everything on a planet, you can’t be sure without observation over time.
And since the theory posits that it would take millions of years to really demonstrate this to be true, humanity cannot test it enough to be certain. So all we’re left with is a scientific theory: a functional method of interpreting data. In other words, it cannot be properly or accurately describe as fact.
This is true about other areas. The word “fact” is thrown around so casually with science and is defended angrily by people who really ought to know better. Cosmology does this a lot. Its a fact that the universe is expanding from an unknown central explosive point (although there is a fair amount of data that’s throwing this into question). We can’t know because we can’t have enough data and there hasn’t been long enough to really test this.
Michael Crichton’s criticism of global warming was along these lines. He didn’t deny anything, he just said its too big and complex a system that we understand far too little about to even attempt to make any absolute or authoritative statements about it. Science has gotten us far beyond our ability to properly measure or interpret the data at hand, but some still keep trying to make absolute statements anyway.
And that’s the heart of a scientific theory. It isn’t like a geometric theorem (a statement or formula that can be deduced from the axioms of a formal system by means of its rules of inference), or a theory that Sherlock Holmes might develop (a proposed explanation whose status is still conjectural). A scientific theory is a system of interpreting data (a coherent group of general propositions used as principles of explanation for a class of phenomena). It’s a step beyond a hypothesis, which is simply speculation or a guess, but is not proven fact.
Confusing theory with fact is really not excusable for an educated person, but some theories are so wedded to worldviews and hopes that they become a matter of argument and even rage. Questioning that theory means you’re an idiot, uneducated, worthless. If you doubt this theory, you’re clearly someone who is wrong about everything and should be totally ignored in life, even showered with contempt.
For all its rich vocabulary, English fails to correctly differentiate among the various uses of the word “theory”, which allows propagandists and outright frauds to confuse the issues and obscure the difference between what science can say about an issue and what believers desperately want to be true.