Introduction to Philosophy by Jacques Maritain

Inspired by the Thomistic Revival called for by Leo XIII, Maritain relies heavily on Aristotle and St. Thomas Aquinas to shape a philosophy that, far from sectarian theology in disguise, is driven by reason and engages the modern world.

Origins of Philosophy

Primitive man was able to deduce some truths about the nature through common sense, though the great feat of philosophical knowledge was not easy to discover and in most cases was wound too closely with myth and religion.

The Greeks and Indians were the first to sucessfully isolate philosophy from religion, and only in Greece would the proper path to philosophical knowledge be fully uncovered.

Maritain chooses to zero in on the progression of Greek philosophy from Thales of Miletus (624-546) to Aristotle (384-322), as this period lays the foundation for all Western philosophy. This progression can be broken down into three epochs:

Formation (pre-Socratic)
Crisis (Sophists and Socrates)
Fruitful Maturity (Plato and Aristotle)

Formation

During this period philosophers such as Thales, Anaximenes (588-524), Heraclitus (540-475), and Anaximander (610-547) were searching for the material cause of all things. But unable to look much beyond the physical world, they chose things such as air, fire, water, or some fusion of all contraries called the apeiron (the infinite or boundless).

Notable philosophers from this period include:

Heraclitus: Proposed that all things are in a state of flux, and that fire is the primary substance.
Democritus (470-361): Proposed that all things are made of indivisible particles called atoms.
Anaxagoras (500-428): Proposed that everything contains a portion of everything else, and that mind (nous) is the ordering principle of the universe. Which by itself is uninteresting, but would lead Aristotle to later discover the concept of first matter.

Crisis

As the Greeks began to achieve a formulation of philosophical knowledge, they became overconfident in their abilities, creating the Sophists, who were much more concerned with having knowledge and using to for gain, than actually in a search for truth.

Socrates (470-399) emerged as a response to the Sophists, seeking to understand things by their essences through dialectical reasoning. It is through him and his student Plato that philosophy would reach its first high point.

Fruitful Maturity

Definitions

Dialectical Reasoning: A method of questioning and answering to arrive at the essence of things.
Evolutionism: The belief that all things evolve from simpler forms.
Hylozoism: The belief that all matter has life.
Law of Non-Contradiction: A thing cannot both be and not be at the same time and in the same respect.
Material Cause: That out of which a thing is made.
Materialistic Monism: The belief that all things are made of one material substance.

Quotes

Pythagoras who first invented the term philosophy (love of wisdom), observing that wisdom belongs in the strict sense to God alone, and for that reason not wishing to be called a wise man, but simply a friend or lover of wisdom.