This article first appeared as a book chapter in the <italic>Handbook of Philosophy and Public Policy</italic>, edited by David Boonin and published by Palgrave in 2018. I was tasked with finding a test case of freedom of speech and inquiry from the sciences, in the larger context of free speech issues as related to public policy and the law. I have already written extensively about evolution and creationism, most notably in my 1997 book <italic>Why People Believe Weird Things</italic> and my 2006 book <italic>Why Darwin Matters</italic>, so here I engage the creationist movement as a free speech issue inasmuch as its proponents hold a minority viewpoint as far as the scientific community is concerned. Nevertheless, I contend that they should be free to believe, teach (and preach) whatever they like about the origins and diversity of life, and that, in the well-trodden principle, sunlight is the best disinfectant (to which Supreme Court Justice Louis Brandeis added “electric light the most efficient policeman”).