To start with, Maritain is a Thomist, following in the intellectual traditions of St. Thomas Aquinas, who in turn draws upon Aristotle. Maritain's approach in this book is to first trace this history of philosophy up to Aristotle. For this, he posits primitive traditions, discernable from both theology and a reasonable induction from historical evidence, which contain wisdom that is common to all mankind globally. He seeks remnants of these traditions in pre-Greek Indo-European civilizations: Persian, Indian, and Chinese. After surveying these, he proceeds to Greek thought: the pre-Socratics, the Sophists, Socrates, Plato, and finally Aristotle. Maritain sees the ancient Persian, Indian, Chinese, and pre-Socratic Greeks as derived from healthy primitive traditions (although in corrupted form). The work of philosophy, in part, is to recover the ancient wisdom and ground it in a system of reason and dialectic.
Upon stating in brief form what he sees as Aristotle's achievements are, Maritain changes his method. He does not follow, as most historical texts would, with a discussion of late antiquity and modern philosophers. For example, do not get a sketch of Descartes in historical context. Rather, Maritain discusses the structure of philosophy as a body of knowledge. That structure is itself determined by Thomist philosophy. Maritain discusses the boundaries of philosophy -- how it is distinct from the empirical sciences, for example, and how it relates to them. He contrasts the Thomist view on philosophy with alternatives in modernity. He then gives an account of the fields of philosophy:
- Logic (a sort of preamble to philosophy proper)
- Theoretical philosophy (speculative, related to understanding of the world)
- Philosophy of mathematics and nature
- Ontology and metaphysics
- Natural theology
- Practical philosophy (related to human action)
- Philosophy of art and technology
It's a very rigorous and systematic book with a good deal of common sense. It explains a lot of Thomism in a very detailed way and makes an excellent reference for those looking to understand this point of view. Thomism can be a bit dry. Maritain goes a long way to guiding the reader to see motivations and connections. For example, one can struggle Aristotle for years and not find as clear an explication of metaphysical terms such as essence (being inasmuch as it can be understood), substance (being inasmuch as it primarily is), and act and potentiality (being inasmuch as it is the subject of change and motion). For anyone interested in Thomism, this book is a find.