As 70-year-old philosophy professor Sidney Hook conducted his last class at New York University after 45 years of teaching there, he said he would break one of his rules and try to explain his own philosophy. “Though there is no substitute for intelligence, it is not enough,” said Hook. “There are human beings who have intelligence but do not have the moral courage to act on it. On the other hand, moral courage without intelligence is dangerous. It leads to fanaticism. Education should develop both intelligence and courage.”