This course is an introduction to philosophical logic founded on Aristotelian and Thomistic principles. Starting with a reflection on the aim and nature of logic, the course is divided according to the three acts of the intellect: (I) simple apprehension (concepts, terms, and definitions based on the 10 predicaments and 5 predicables; (II) judgment and different kinds of propositions; and (III) reasoning which leads In to syllogism, including an explanation of different figures, moods and rules of syllogism. The course concludes with an explanation of categorical syllogisms.