“What evidence do you have for that idea?” It is a simple question, but one asked far less than it should be. Too often, we hear justifications such as, “Everybody knows that ...,” “It’s what I’ve heard,” or “It’s just what I believe.” But formulating explanations based on evidence is a distinguishing characteristic of scientific inquiry. If our students routinely make decisions without searching for and evaluating evidence, how can they reject the charlatans of pseudoscience and learn to critically evaluate the important questions that they encounter daily, from global warming to personal health issues? “It’s just what I believe” is simply not good enough.