A System of Logic is 19th-century English philosopher John Stuart Mill's treatise on the study of exact thinking, or ratiocination, and inductive reasoning. In his essay, Mill writes about his empiricist and utilitarian beliefs. Excerpt: "There is a great diversity among authors in the modes which they have adopted of defining logic, as in their treatment of the details of it. This is what might naturally be expected on any subject on which writers have availed themselves…"