Children should have the same First Amendment rights as adults except when it can be empirically shown that the children in question differ from minimally normal adults in relevant intellectual competencies and would, as a result, be likely to suffer harm if accorded full First Amendment liberties. In this paper, specific principles derived from this general perspective are proposed. Application of the principles raises empirical questions about the ability of children at various ages to critically analyze what they are exposed to, coordinate multiple points of view, distinguish the personal ideas and religious activities of classmates from government-endorsed values and quidelines, and understand their rights to form and express their own ideas and to act in accord with their own religious views. The proposed principles help identify the sorts of empirical evidence relevant to public school controversies, clarify how such evidence may be applied in a legal context, and highlight areas in which the need for further research is particularly critical. The principles are applied to controversies surrounding censorship of student expression, student freedom of association, selection and removal of textbooks and school library books, religion and prayer in public schools, secular humanism, evolution/creation, and values and morality in education. (RH)