Metaphysics refers to ideas or entities that exist independently of the world of space and time and are not sensible objects like tables, chairs, or rocks—examples include pure ideas, spiritual entities like God or angels, and things that exist outside of immediate everyday experience.

Philosophy comes from two Greek words meaning 'love' and 'wisdom' or 'knowledge,' and represents a passion for knowledge that goes beyond practical concerns and the intellectual tradition of the West.

Understanding philosophical material is only the first stage; after understanding comes absorption, and after absorption comes action—the action stage is outside the scope of these lectures but represents the ultimate purpose of philosophical education.

Ethics is the philosophical inquiry into right and wrong, moral obligations, and what we ought and ought not to do—it investigates the non-animal, free-choosing aspects of human beings and asks what kind of people we are or could become.

The pre-Socratic physicists, in treating the world as made up only of atoms and the void, were the first philosophers to assert that nature alone (without gods, spirits, or a transcendent realm) is ontologically fundamental, establishing the origin of philosophical materialism in the Western tradition.

Physics, in the philosophical sense, is our general theory of nature and the world of sense perception—tables, chairs, component parts of material objects, and larger entities like suns, galaxies, and worlds—explaining the world of space and time around us.

Every epistemology (theory of knowledge) necessarily entails a theory of the knower—a philosophical psychology—because knowledge always involves some person doing the knowing, and different philosophers' conceptions of mind and consciousness are characteristic of and directly tied to their entire philosophical projects.

To maximize learning from a course in the history of Western philosophy, students must have the courage not just to hold their existing convictions but to attack them, call them into question, and imaginatively explore what they would believe if their current assumptions were completely wrong.

Ontology is the philosophical discipline that allows analysis and thinking about the kind of existence that things have—it distinguishes between kinds of beings, attributing different status in a hierarchy and different modes of reasoning applicable to each kind of being.

Logic is a system of rules for deriving true inferences—if you start with true premises and follow the rules of logic, you will always arrive at true conclusions; it is fundamentally a set of rules for organizing thinking to ensure correct answers from true assumptions.

Epistemology is the inquiry into knowledge itself—it investigates what kinds of things we can know and what kinds of knowledge we can have of different kinds of things, recognizing that different domains of knowledge (arithmetic, empirical facts, morality, politics) may involve fundamentally different types of knowing.

Aesthetics is the theory of the beautiful and involves reasoned inquiry into what human beings find beautiful, whether beauty exists in the object or in the psyche/mind, and what role beauty plays in other judgments including judgments of right and wrong, political order, and how we ought to live.

Political theory investigates how societies ought to be organized, how governments ought to function, and how justice ought to be dispensed—and it is fundamentally connected to ethics because the city or human collectivity is conceptualized as being like an individual human soul only increased in size and proportion.

There are only two basic ontological answers to the fundamental question 'What is?' in the Western intellectual tradition: first, that what is, is nature—tables, chairs, objects of sense perception with no gods, spirits, demons, or non-physical entities; and second, that nature exists plus something else—a transcendent realm like heaven, hell, or the world of forms.

Plato's metaphysical tradition posits a world of forms (a realm of pure ideas and pure thought that is more real, permanent, and everlasting than the world of becoming, change, and flux that humans inhabit) functioning analogously to the Christian/Jewish heaven—a transcendent realm where something divine rains down its significance and will on the natural world.

The intellectual history of the West can be understood as a braid formed by two traditions: Athens (representing liberated rationality and human freedom) and Jerusalem (representing reverence, piety, and faith in God), which are foundational to the mythology, orientation toward right and wrong, and metaphysical conceptions characteristic of Western culture.

Socrates is the patron saint of free and rational inquiry, and Athens is the cultural home of the idea that nothing human is foreign to us, that what is potentially true for one human being is accessible to all through one common logos (rationality) that unites all humans and allows them to dispel the darkness of myth and irrationality.

What is unique and remarkable about Greek culture, compared to contemporaneous cultures, is the drive toward secular knowledge—a thorough turnaround from the earlier tradition organized entirely around myths, exemplified by the Greek pre-Socratic physicists and sophists.

In the Christian New Testament tradition, logos means 'word' (as in 'In the beginning was the Word'), not free rationality—the primary reality is the authoritative, fundamental, divine word of God; this difference in meaning has been the source of endless confusion in Western philosophy between devotees of Athens and Jerusalem.

Mythos means story, but more fundamentally an archetypical story—a narrative about fictional people and events that, despite its fictional particularity, has universal applicability and speaks fundamental truths about the human condition indirectly and ambiguously, not through mathematical equations.