Sean McDowell | January 27, 2016

Why Evolution Is Not "Just a Theory"

One of my favorite presentations to do at universities, schools, conferences, and churches is my Atheist Encounter, in which I interact with the audience while role-playing an atheist. After briefly setting up my character (which involves putting on my “atheist glasses”), I then take live questions from the audience and do my best to defend atheism so Christians can see how well—or how poorly—they defend their faith.

The topic of evolution inevitably comes up. And more often than not, some well-meaning Christian will say something like: “How can you say evolution is a fact, when it’s called a theory?” The questioner seems to be under the impression that since evolution is called a theory it is just a blind guess, and can be dismissed without consideration of the actual evidence.

Here is how I typically respond (in my role-playing mode): “I think you are confused about what theory really means. In popular verbiage, theory often means a conjecture, an uneducated guess. But in the scientific world, a theory can mean an idea that has empirical support and explains a wide range of data. So, yes, evolution is a theory, but the evidence is overwhelming and should be accepted nonetheless.” And then the conversation typically moves on to the actual evidence.

For the record, I do not believe in neo-Darwinian evolution. I don’t think there is sufficient evidence to justify its grandiose claims. In fact, I have written a critique of some of the main arguments for Darwinism in my book Understanding Intelligent Design (with William Dembski). But I also think it’s a big mistake for anyone—and especially Christians—to simply dismiss evolution because its called a theory. In fact, to dismiss evolution with such ease portrays remarkable misunderstanding of how theory functions in science.

Gerald Rau explains:

In nonscientific speech, theory is often used to refer to a vaguely supported guess, as in ‘I have a theory about that.’ In science the term theory commonly refers to a unifying idea tying together a large body of related knowledge statements, including tested hypothesis, laws, definitions, and a broad range of empirical data.

A common misconception is that an idea begins as a hypothesis, moves to a theory, and then finally becomes a law once sufficient evidence is compiled. In reality, says Rau, law and theory are two completely different entities. Rau clarifies the difference between the two concepts:

A law is a pattern in the data, often expressed mathematically. A law explains and predicts what happens, but does not provide an explanation of how or why it happens, which is the role of a theory.”[1]

My point in this blog is not to discuss the merits of evolution. Rather, my point is that evolution should not be dismissed simply because its called a theory. Such a move is shallow and misguided. Many other scientific theories often have considerable support (e.g., consider the general and special “theories” of relativity).

Evolution, like all scientific ideas, deserves to be judged on its merits. If you are going to be an evolutionary critic, then do the hard work of actually reading the evidence presented in its favor and offering a reasoned response. It is not good form to dismiss evolution simply because it’s a theory. In fact, such a move is not unlike the atheist who dismisses the evidence for Christianity with the simplistic slogan, "Well, its just blind faith anyways." Both of these moves are simplistic, misguided claims that ignore the evidence. And whether you are a Christian or an atheist, we should all be able to agree that truth and evidence matter.

Sean McDowell, Ph.D. is a professor of Christian Apologetics at Biola University, a best-selling author of over 15 books, an internationally recognized speaker, and a part-time high school teacher. Follow him on Twitter: @sean_mcdowell and his blog at

[1] Gerald Rau, Mapping the Origins Debate (Downers Grove, IL: InterVarsity Press, 2012), 34.

Sean McDowell, Ph.D. is a professor of Christian Apologetics at Biola University, a best-selling author, popular speaker, and part-time high school teacher. Follow him on Twitter: @sean_mcdowell, TikTok, Instagram, and his blog: