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

This first volume presents Zigliara’s pedagogical summary of classical philosophy, designed for academic instruction within the Thomistic tradition. Following the metaphysical and epistemological framework of Thomas Aquinas, it introduces the foundational disciplines of logic and ontology as the basis for all philosophical inquiry.

The work begins with logic, treating it as the art and science of correct reasoning. Zigliara explains the structure of concepts, judgments, and syllogisms, emphasizing the laws of thought and the proper method for attaining truth. Logic is presented not as an abstract formalism, but as an instrument ordered toward real knowledge of being.

The second part introduces ontology, or general metaphysics, focusing on being as such. It examines fundamental notions such as being, essence, existence, unity, truth, and causality, establishing the basic categories through which reality is intelligible. Zigliara emphasizes the objective reality of being and the correspondence between thought and reality, in line with classical Thomistic realism.

Throughout the volume, Zigliara maintains a clear didactic structure, aiming to provide students with a systematic introduction to philosophical principles that serve as the foundation for further studies in natural philosophy, psychology, and metaphysics.