Feynman opposed rote learning or unthinking memorization and other teaching methods that emphasized form over function. "Clear thinking" and "clear presentation" were fundamental prerequisites for his attention. It could be perilous even to approach him unprepared, and he did not forget fools and pretenders. In 1964, he served on the California State Curriculum Commission, which was responsible for approving textbooks to be used by schools in California. He was not impressed with what he found. Many of the mathematics texts covered subjects of use only to pure mathematicians as part of the "New Math". Elementary students were taught about sets, but: