What Is a Theory?
Barbara Forrest
backProfessor of Philosophy
Southeastern Louisiana University
"Only a Theory"
Creationists often reject evolution by saying that evolution
is, quote, "only a theory." And that betrays either a deliberate or
an unintentional misunderstanding of what a scientific theory is. Gravity is a
theory—gravitational theory. Cell theory—all living things are
constructed of cells. Electromagnetic theory, right? Germ theory? Germs make
people sick. I mean, when you call evolution a theory, when you use the term
"evolutionary theory," that's a very, very strong thing to
say.
A theory in science is an explanation. It's a large system which has withstood some very, very rigorous testing, literally attempts to debunk it, and has survived all of those attempts. So when creationists try to dismiss evolution as "only a theory," they are misusing the word theory. They are using it in the ordinary sense, the non-scientific sense, of a hunch or a guess, and that's not what it means at all.
If you have a scientific theory, you have already done years, decades, of scientific work, hard scientific research that you have offered to the scientific community for their evaluation. But never a single time has any intelligent-design creationist ever done that. Yet they've created a public relations concoction that they present to the public and to the media that they have some cutting-edge science that really needs to be taught to children—that there is another side to this issue and it's only fair to tell it to the kids.
Well, there aren't two scientific sides to this issue, because there aren't two scientific theories. There's only one. And if you believe that children should be told the truth, you have to tell them that the only scientific theory which explains the shape of life on Earth is evolutionary theory. And if you tell them anything other than that, you're not telling them the truth, and that's hardly fair.
Kevin Padian
backPaleontologist
UC Berkeley
A Solid Theory
I don't know where people get the idea that evolution is a
theory in crisis. It is a theory in the sense that we use the word in science;
that is, it is the strongest construct that we use.
The difference between what a theory means to the average person and what it means to a scientist is really completely opposite, because theories are very strong concepts in science. A theory is something that has been tested and tested over and over again, built on, revised. It continues to be reworked and revised.
The theory of evolution today is not like it was a hundred years ago. We have molecular genetics. We have developmental evolutionary biology. We have far more fossils than we had before. We have better kinds of phylogenetic techniques. Everything is improving through science. All of these things are becoming much better and better known.
And, so there's no crisis in evolution. It's healthier than ever. Do we have controversies? Sure, we do. Sure, we do. But, they're not about whether evolution occurred, or whether you can possibly see a unity to the ancestry of life. Those issues were settled. They were settled a century and a half ago.