Logic

Webster's Dictionary

(1): ( n.) A treatise on logic; as, Mill's Logic.

(2): ( n.) The science or art of exact reasoning, or of pure and formal thought, or of the laws according to which the processes of pure thinking should be conducted; the science of the formation and application of general notions; the science of generalization, judgment, classification, reasoning, and systematic arrangement; correct reasoning.

The Nuttall Encyclopedia

The science of correct thinking or of the laws which regulate thought, called also dialectics; or in the Hegelian system "the scientific exposition and development of those notions or categories which underlie all things and all being."