No one can be a great thinker who does not recognise, that as a thinker it is his first duty to follow his intellect to whatever conclusions it may lead. Truth gains more even by the errors of one who, with due study and preparation, thinks for himself, than by the true opinions of those who only hold them because they do not suffer themselves to think. -John Stuart Mill, in On Liberty Often mentioned in the same breath with the Communist Manifesto, On Liberty-perhaps the greatest work from British political philosopher John Stuart Mill-is one of the most profound and most hotly debated works of the 19th century. Is it a classic plea for human freedom and intellectual development... or is it factually wrong and morally offensive? English philosopher and politician JOHN STUART MILL (1806-1873) was one of the foremost figure of Western intellectual thought in the late 19th century. He served as an administrator in the East Indian Company from 1823 to 1858, and as a member of parliament from 1865 to 1868.