Monday, July 15, 2013

"Evolution is a theory the way gravity is a theory."

In an article about creationism vs theory of evolution on Slate posted here, Laura Helmuth makes a statement I'd like to correct. In chapter one of my introductory chemistry text, I require my students to know the difference between a law and a theory. Apparently, Laura Helmuth needs to review her introductory science and familiarize herself with this difference.

Yes, evolution is a theory. It is a large-scale explanation about how life on earth evolved: it includes supporting data, scientific laws, a series of tested hypotheses, and an overall picture of what the process entailed. It is a model of nature. And like any model, it has flaws. It provides us with an imperfect, incomplete picture of what happened over billions of years. It cannot be easily, readily and completely tested and proven over and over again.  Just like any theory, new data may tweak it at any time. There are endless hypotheses to test about this theory. I am sure we do not have complete information, to date, about the evolutionary process. It is an incredibly complex process.

This is in contrast to the scientific law of gravity. The law of gravity holds true over and over again (on earth anyway) based on repeated observable circumstances. You can drop a ball a thousand times and it will always fall toward the ground. It is a repeated observation for which there is no complexity, no unanswered question or further investigation to be done. (This excludes the behavior of gravity on a subatomic scale or out in space.)

Thank you for the article, Laura. I just want to make sure all of your vocabulary is correct.