Mill's Logic, first published in 1843, became an instant cult book, and firmly established Mill as the leader of the empirical school of logic. A System of Logic is the first major installment of his comprehensive restatement of an empiricist and utilitarian position. It begins the attack on "intuitionism" which Mill carried on throughout his life, and makes plain his belief that social planning and political action should rely primarily on scientific knowledge, not on authority, custom, revelation, or prescription.