Creationists love to blather on about how evolution is just a theory. It’s a great little sound byte that crops up almost everywhere evolution is doubted, tainted or otherwise misunderstood. The problem is how it undermines and misrepresents the meaning of a scientific theory, a testable (and well tested) explanation of the facts that also makes specific falsifiable scientific predictions.
In truth, evolution is both a fact and a theory. Let me explain this using gravity as an example.
There is the observable fact we call ‘gravity’ – Things fall when you drop them. Then we have an ever-changing theory of gravity we use to explain those observed facts. Our current theory started with Newton and was later added to by Einstein. Regardless of what theory we use or where that theory stands, it doesn’t change the fact that things fall when you drop them.
Now let’s change ‘gravity’ to ‘evolution’.
There is the observable fact we call ‘evolution’ – Species evolve over time. Then we have an ever-changing theory of evolution we use to explain those observed facts. Our current theory started with Darwin’s theory of Evolution by Natural Selection and has since been added to and changed by thousands of scientists over the years. Regardless of what theory we use or where that theory stands, it doesn’t change the fact that species evolve over time.
This is one of the reasons I loved it when Carl Sagan noted in his Cosmos series, “Evolution is a fact. It really happened.” Evolution did really happen. Species evolved over time. It’s observable. It’s a fact. And the best theory we have to date to explain these observed facts is evolution by natural selection.
Micro-evolution vs. Macro-evolution.
Now, a lot of creationists like to meet halfway by saying they accept micro-evolution but not macro-evolution. I don’t differentiate between the two, but just to explain – Micro-evolution is used when talking about small changes within a single species. Macro-evolution is used when talking about a single species becoming two separate species. In truth, there is only one kind of evolution. Accepting micro-evolution but not macro-evolution (indeed, even acknowledging a difference between the two) is usually employed as a method for religious people to make room for God in their otherwise purely scientific and reasonable view of nature. This is the God of the Gaps dilemma many religious people face. As evidence from various areas of science fills in the remaining gaps, God (or the need for a god) gets smaller and smaller until there are no gaps left for him to inhabit.
This is when many religious people fall back on what Stephen Jay Gould called NOMA or Non-Overlapping Magisterium that says;
The net, or magisterium, of science covers the empirical realm: what is the universe made of (fact) and why does it work this way (theory). The magisterium of religion extends over questions of ultimate meaning and moral value. These two magesteria do not overlap…
As Richard Dawkins points out in his book The God Delusion, “This sounds terrific – right up until you give it a moment’s thought.” After all, by what means does religion gain insight into life’s ultimate meanings and moral values? But that’s a question for another post.