This seminal work sets out to systematize the principles of reasoning and inquiry, building upon the best ideas of previous thinkers rather than claiming a revolutionary break with the past. The author begins with a foundational analysis of language, arguing that names, propositions, and terms must be thoroughly understood before one can examine the processes of inference. A proposition is scrutinized not merely as a combination of ideas, but as an assertion respecting things and the objective relations between them, categorized into existence, coexistence, sequence, causation, and resemblance.
The inquiry then transitions into the nature of reasoning, specifically addressing ratiocination and the syllogism. While defending the utility of syllogistic reasoning against its modern detractors, the author reinterprets its function as part of a broader framework of proof. The central problem of the work becomes the justification of induction—the process by which we draw general conclusions from particular observations and establish the laws of nature and universal causation.
Throughout the text, the author addresses contemporary controversies, engaging critically with rival philosophers such as Whewell and various idealist thinkers. He maintains that all knowledge derived through reasoning ultimately rests on primitive data known by immediate consciousness or intuition, while logic serves as the supreme arbiter of evidence and proof.
The final portions of the work lay the groundwork for extending logical and scientific methods beyond physical science into the moral and social phenomena of human life. By treating logic as the ars artium—the science of science itself—the author provides a rigorous defense of critical thinking and scientific inquiry that remains a cornerstone of classical philosophy.
