Is it Theory or is it Fact?
I spend a lot of time on the internet. Recently I’ve seen a lot of memes going around about the theory of evolution and the theory of gravity. My brain immediately pops back to a scene in the Princess Bride in which Inigo Montoya (Mandy Patinkin) looks at Vizzini (Wallace Shawn) and says “You keep using that word. I do not think it means what you think it means.” So what then, does theory actually mean?
Tyrannosaurus rex no longer roams the earth, at least not the last time I checked. We do know, from fossil records, that members of the species did roam the earth at some point in time. We also know that if you step off the Empire State Building (or any other structure), your body and its mass will be drawn to the earth’s surface. Those are all factual statements. No matter how many times you test them, they will remain true. At least for as long as Jurassic Park remains a work of science fiction and as long as the earth maintains its own mass (as a scientist I have to qualify every fact, it’s habit). The problem with any fact is that we are usually limited in our ability to explain why T. rex no longer roams the earth, or what happened to its genetic traits after extinction, or why we fall to the ground when our feet fail us.
As scientists, our job is to observe and test things. I can observe someone stepping off the Empire State Building. I can start a stopwatch the moment they do so. I can observe their impact and stop the watch, recording the amount of time it took for them to fall. Knowing the distance traveled, I can calculate the average rate at which they fell. If we do this over multiple distances, we learn that an object doesn’t fall at a constant velocity, but a changing one, also known as a rate of acceleration (I’m simplifying this because physics is my worst subject, but you should get the point). Sometimes direct observation is easy, but more often than not it’s incredibly difficult. While we can directly observe the effects of gravity, it’s much harder to observe the mechanics that cause it. This is where theory comes in.
Following along the lines of simplicity, theory is (basically) how we explain the cause of some fact we observe. It’s built on assumptions (or explanations) that we make about how the world works. As scientists, we then test those assumptions, either disproving or failing to disprove them as we go (at least that’s how it’s supposed to work). If we disprove them, then we have to develop an alternative idea as to why something behaves the way it does, and test that. If we fail to disprove our assumptions then we can say, with qualifying statements, that our theory is a good explanation. Because of this process it’s not unusual for theory to change (or evolve) as we gain new tools for testing and understanding.
When Darwin formed his theory of Natural Selection, it was in response to a simple fact: creatures on this earth are always changing. Insects become resistant to pesticides, moths in England have changed their color patterns to adapt to urban pollution, etc.. Darwin simply looked at this fact and attempted to explain how and why that change took place. Over the years that theory has changed, expanded, and been contextualized (not all evolution is a result of natural selection). It’s a big theory in its modern form, and while it doesn’t explain all of Life, the Universe, and Everything, it’s supported by a tremendous body of research. Each experiment represents an attempt to disprove some part of the underlying assumption of how and why and to what extent a creature adapts and changes in relation to its environment. The same can be said for gravity. So the next time you hear someone say that something is just a theory, please feel free to (politely) point out to them that the theory in question exists in response to some observed fact and that science is doing its best to sort out the good explanations from the bad.
And in other evolutionary SCIENCE! related news
First we start with two stories from right here in Alaska.
The first is a cold blooded tale of the only living vertebrates in the world to lack red blood cells, making their blood a cloudy white color instead of red. Ladies and gentlemen, I give you THE ICEFISH.
The second home state story is about a unique adaptation found in lampreys – lungless creatures that hiccup in the presence of carbon dioxide. For a good write up on this story visit Kelsey Gobroski’s blog, Boreal Bites!
Here are two evolving stories courtesy of Scientific American:
Speaking of disproving assumptions, two scientists recently challenged a commonly held theory on the role of duplication in genetic mutations by asking the question; “Which came first, the mutation or its necessity?”
Next we have a story of scientists who are challenging the mechanics of flight used by Microraptor, a crow like creature that represents an evolutionary transition from tiny dinosaur to dinner plate bird.
And last, but certainly not least:
And a very interesting historical analysis of science in politics, (with some pretty poignant criticism of the ivory tower of academic science) and what it means in the face of this election cycle.