Hugo Black,
Epperson v. Arkansas — Concurrence
(1968)
“ Under this statute as construed by the Arkansas Supreme Court, a teacher cannot know whether he is forbidden to mention Darwin's theory, at all or only free to discuss it as long as he refrains from contending that it is true. It is an established rule that a statute which leaves an ordinary man so doubtful about its meaning that he cannot know when he has violated it denies him the first essential of due process. ”
