John Stuart Mill (1806–1873) was a British philosopher, political economist, and civil servant who is widely considered the most influential English-speaking philosopher of the nineteenth century. He received an extraordinarily intensive education from his father, beginning Greek at age three and Latin at eight—an upbringing that led to a mental crisis at age twenty. His recovery through poetry and feeling shaped his mature outlook. In Utilitarianism (1863), he refined Bentham's "greatest happiness" principle by introducing a qualitative distinction among pleasures, arguing that it is better to be Socrates dissatisfied than a fool satisfied. His On Liberty (1859) articulated a passionate defense of individual freedom and the harm principle—that the only legitimate reason to restrict individual action is to prevent harm to others. He was also a pioneering advocate for women's rights; The Subjection of Women (1869) argued forcefully for complete equality between the sexes. As a member of Parliament, he became the first person in that body's history to call for women's suffrage.