A System of Logic, Ratiocinative and Inductive

Induction and Deductive Reasoning

Mill's central project is to provide a comprehensive account of both deductive (ratiocinative) and inductive logic. He meticulously outlines the structure of syllogisms and other deductive inferences but devotes the majority of his work to induction. He argues that induction, the process of inferring general laws from particular observations, is the true basis of scientific discovery and empirical knowledge. He proposes the Five Canons of Induction (Methods of Agreement, Difference, Joint Method, Residues, and Concomitant Variations) as systematic ways to discover causal relationships.

Causation and Scientific Method

A significant portion of the 'Logic' is dedicated to defining and discovering causation. Mill argues that causal laws are discovered through empirical observation and experiment, not through a priori reasoning. He defines cause as the invariable and unconditional antecedent of a phenomenon, emphasizing the necessity of understanding the full set of conditions. His Canons of Induction are specifically designed as methods for identifying these causal relationships, forming the core of his scientific methodology.