The federal Education Minister, Christopher Pyne, is justifiably concerned that some teachers are biased and unfair, knowingly or unknowingly, in their presentation to students of controversial issues. Yet this is part of the paradox of freedom. We want to teach what we believe to be true, and fear the effects of those who teach what we believe to be false, even if those who teach it are sincere. Many issues are essentially contestable. Men and women of equal intelligence, experience and integrity may legitimately come to different and even incompatible conclusions from studying the same evidence. This does not mean…