John Stuart Mill (May 20, 1806 – May 8, 1873), aka JS Mill, an English philosopher and political economist, was the most influential liberal thinker of the 19th century. He was an advocate of utilitarianism, the ethical theory first proposed by his godfather Jeremy Bentham.
John Stuart Mill was born in Pentonville, London, the eldest son of James Mill. Mill was educated by his father, with the advice and assistance of Jeremy Bentham and Francis Place. He was given an extremely rigorous upbringing, and was deliberately shielded from association with boys his own age. His father, a follower of Bentham and an adherent of associationism, had as his explicit aim to create a genius intellect that would carry on the cause of utilitarianism and its implementation after he and Bentham were dead.
His feats as a child were exceptional; at the age of three he was taught the Greek alphabet and long lists of Greek words with their English equivalents. By the age of eight he had read Aesop's Fables, Xenophon's Anabasis, and the whole of Herodotus, and was acquainted with Lucian, Diogenes Laėrtius, Isocrates and six dialogues of Plato (see his Autobiography). He had also read a great deal of history in English and had been taught arithmetic.
A contemporary record of Mill's studies from eight to thirteen is published in Bain's sketch of his life. It suggests that his autobiography rather understates the amount of work done. At the age of eight he began learning Latin, Euclid, and algebra, and was appointed schoolmaster to the younger children of the family. His main reading was still history, but he went through all the Latin and Greek authors commonly read in the schools and universities at the time. He was not taught to compose either in Latin or in Greek, and he was never an exact scholar; it was for the subject matter that he was required to read, and by the age of ten he could read Plato and Demosthenes with ease. His father's History of India was published in 1818; immediately thereafter, about the age of twelve, John began a thorough study of the scholastic logic, at the same time reading Aristotle's logical treatises in the original language. In the following year he was introduced to political economy and studied Adam Smith and David Ricardo with his father--ultimately completing their classical economic view of factors of production.
Mill worked for the British East India Company, but he was also a Liberal member of Parliament. Mill advocated easing the burdens on Ireland, and basically worked for what he considered reason. In Considerations on Representative Government Mill called for various reforms of Parliament and voting, especially proportional representation and the extension of suffrage.
In 1851 Mill married Harriet Taylor after 21 years of friendship. Taylor was a significant influence on Mills's work and ideas during both friendship and marriage. His relationship with Harriet Taylor inspired Mill's advocacy of women's rights.
One foundational book on the concept of liberty was On Liberty, about the nature and limits of the power which can be legitimately exercised by society over the individual. One argument that Mill formed was the harm principle, that is, people should be free to engage in whatever behavior they wish as long as it does not harm others.
John Stuart Mill only speaks of negative freedom in On Liberty, a concept formed and named by Isaiah Berlin (1909-1997). Isaiah Berlin suggests that negative freedom is an absence or lack of impediments, obstacles or coercion. This is in contrast with his other idea of positive freedom, a capacity for behavior, and the presence of conditions for freedom, be they material resources, a level of enlightenment, or the opportunity for political participation.
Thus Mill argued that it is Government's role only to remove the barriers, such as laws, to behaviors that do not harm others.
Mill's magnum opus was his A System of Logic , which went through several editions. There he evaluates Aristotle's categories and gives his own system. He gives his theory of terms and propositions and focuses on the inductive process. William Whewell's History of the Inductive Sciences (1837) was a chief influence.
The reputation of this work is largely due to his analysis of inductive proof, in contrast to Aristotle's syllogisms, which are deductive. Mill formulates five methods of induction -- the method of agreement, the method of difference, the joint or double method of agreement and difference, the method of residues, and that of concomitant variations. The common feature of these methods, the one real method of scientific inquiry, is that of elimination. All the other methods are thus subordinate to the method of difference.