The elements of logic. [electronic resource] : In four books. Book I. Of the Original of our Ideas, their various Divisions, and the Manner in which they contribute to the Increase of Knowledge; with a Philosophical Account of the Rise, Progress, and Nature of Human Language. Book II. Of the Grounds of Human Judgment, the Doctrine of Propositions, their Use in Reasoning, and Division into Self-Evident and Demonstrable. Book III. Of Reasoning and Demonstration, with their Application to the Investigation of Knowledge, and the common Affairs of Life. Book IV. Of the Methods of Invention and Science, where the several Degrees of Evidence are examined, the Notion of Certainty is fixed and stated, and the Parts of Knowledge in which it may be attained, demonstrated at large. Designed Particularly for Young Gentlemen at the University, And to prepare the Way to the Study of Philosophy and the Mathematics. By William Duncan, Professor of Philosophy in the Marishal College of Aberdeen.