Summary of Philosophy for the Use of Schools - Logic and Ontology, Volume I - Tommaso Maria Zigliara

This opening volume of Zigliara’s Summary of Philosophy for the Use of Schools provides a structured introduction to the fundamental disciplines of logic and ontology within the Thomistic tradition of Thomas Aquinas. Designed for academic instruction, it presents philosophy as a coherent system grounded in objective reality and ordered reasoning.

The work begins with logic, treated as the instrument of correct reasoning and scientific demonstration. Zigliara explains the formation of concepts, propositions, and syllogisms, along with the principles governing valid inference and the laws of thought.

It then turns to ontology (general metaphysics), examining being as such and its most universal properties. Key topics include essence and existence, act and potency, unity, truth, goodness, and causality. These principles are presented as the foundation of all philosophical knowledge.

Throughout the volume, Zigliara maintains a clear pedagogical style, aiming to form students in disciplined reasoning and realist metaphysical thinking as the basis for further study in natural philosophy, psychology, and theology.