There are two ways to look at anything. That's what I learned from reading Steven Pinker. Actually, I learned it from two Steven Pinkers. One is a theorist of human nature, the author of "How the Mind Works" and "The Blank Slate." The other is a word fetishist, the author of "The Language Instinct" and "Words and Rules." One minute, he's explaining the ascent of man; the next, he's fondling irregular verbs the way other people savor stamps or Civil War memorabilia.