Theories are perhaps the most powerful products to come out of the scientific process. A theory can explain a wide swath of natural phenomena in a single unifying framework. Like general relativity: everything from orbiting satellites to black holes to the history of the universe to waves of gravity all sit under the same roof. The explanatory power of a fully-developed theory is simply unparalleled.
Atomic theory. Germ theory. Natural selection. These are powerful, wide-reaching concepts built over the course of decades and refined refined refined, and layered and layered and layered to keep pushing the boundaries of knowledge.
Theories are the structures that science builds. The artifacts. The things that last. The starting points for even more.
And they all have flaws. There's no such thing as a perfect, all-encompassing theory. There's no such thing as a theory that totally explains everything it sets out to explain. There's no such thing as a theory that is...done. All theories break down at some point, or contain edges that are poorly understood or simply defy explanation.
What's more, all theories have limits. We don't expect general relativity to explain how new species arise, and we don't expect natural selection to provide a trajectory for a solar system probe. And even within their respective domains, the theories themselves tell us when and where they do and do not apply. They have boundaries. Theories are powerful and wide-ranging, yes, but not that powerful.
These flaws and limits in theories are vitally important. It's at the edges where new knowledge is made. It's at the weaknesses of a theory where new wisdom comes.
That's why scientists continue their work even when a theory is well established. Pushing and poking and prodding at the edges. Sometimes testing, looking for flaws. Sometimes growing the theory in a new direction. Sometimes pouring over old results searching for cracks. Sometimes brainstorming a completely new replacement out of whole cloth.
And that's why you should never believe a theory that attempts to explain all the data, perfectly. If an idea comes along that explains a whole host of unrelated phenomena in one fell swoop, it should set your alarm bells ringing. Could it really be that a single idea is able to have that much explanatory power? To leave nothing out? No stone unturned? To have no gaps or sharp edges? To unite so much under a single roof? To have nothing left to work on?
What's more, any theory that claims to explain all the data is going to have issues when the data change. After all, data are wrong. A lot. What seems to be the firm conclusion after a series of experiments can change direction after enough new evidence, and swing back again before finally settling down. All observations and experiments are limited by errors and uncertainties.
Real theories are flexible and adaptable, specifically because of their flaws and limits. Scientists can patch and extend as new evidence becomes available. And if too much contrary evidence accumulates, then the whole thing can be dismantled if need be.
So if a proposed theory crosses your path that explains everything, perfectly and completely, does that maybe seem...too good to be true?