The History of Philosophy
by Dr. Leonard Peikoff
- 24 lectures, 72 hours
- Delivered and recorded in 1970 and 1972
Presented as two complementary twelve-lecture courses—Founders of Western Philosophy: Thales to Hume and Modern Philosophy: Kant to the Present—The History of Philosophy covers the whole of western philosophy from its discovery in Ancient Greece to the twentieth century, including Objectivism. Dr. Peikoff argues that philosophy is the means by which we can understand any human culture and, more broadly, the history and changing course of a civilization. Philosophy is also a live issue, with real questions and answers that have relevance to everyone today. Through a systematic presentation of the most important figures in western philosophy, Peikoff identifies and evaluates the important questions raised by each figure as well as the evidence that each philosopher presented for his ideas. He analyzes the characteristic approaches and issues in major philosophical schools throughout history and identifies how Objectivism answers the main questions raised by historical thinkers.
Download the entire course (1.36 GB) to listen in the audio player of your choice—or listen online starting with Lecture One below. If listening to the course from this website, be sure to make a note of the current lecture and timestamp before leaving so that you can easily resume where you left off.
Download the entire course (1.25 GB) to listen in the audio player of your choice—or listen online starting with Lecture One below. If listening to the course from this website, be sure to make a note of the current lecture and timestamp before leaving so that you can easily resume where you left off.
Study Guides
This course includes study guides, featuring questions and other material designed to help you digest the course content. This material is included both with the individual lectures and below in PDF form.
Founders of Western Philosophy: Thales to Hume
Modern Philosophy: Kant to the Present
Lecture Guide
Summaries of the lecture content are provided below for your reference and convenience.
Founders of Western Philosophy: Thales to Hume
| Lecture 1 | In this lecture, Dr. Peikoff explains the origins and early developments of ancient Greek philosophy. He examines why philosophy was born in Greece and indicates some of the fundamental questions the early thinkers asked that led them to formulate philosophic answers. He reviews the thought of the early pre-Socratics, who reckoned with the questions of change and multiplicity, including Thales, Parmenides, Heraclitus, and Zeno. He concludes with a review of the first school of philosophy in the followers of Pythagoras. |
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| Lecture 2 | In this lecture, Dr. Peikoff finishes his examination of the pre-Socratics by contrasting two major schools of thought that contrasted with Pythagorean idealism, the materialists and the skeptics. Peikoff explains the Atomic school’s deterministic approach that led to materialism and the Sophists’ relativism that led to skepticism. The lecture concludes with a summary of Socrates’ main methodological contributions and an examination of Plato’s metaphysics of dualism. |
| Lecture 3 | Plato’s philosophy is explained in detail in this lecture. Dr. Peikoff presents the full case for Plato’s forms and how that leads to his rationalist epistemology. He reviews in detail the Plato’s theory of knowledge as presented in the argument of the divided line and the Allegory of the Cave. The lecture concludes with an explanation of how Plato’s ethical system and collectivist politics arise from his earlier premises. |
| Lecture 4 | This lecture begins the examination of Aristotle’s philosophy. Dr. Peikoff begins with some metaphysical preliminaries regarding Aristotle’s realism before examining his epistemology in depth. He explains Aristotle’s argument for knowledge based on sense perception, and his theories of explanation and definition. Peikoff discusses Aristotle’s crucial discovery of the principles of logic and his theory of proof. The lecture concludes with an explanation of Aristotle’s metaphysical account of change and its implications for causation. |
| Lecture 5 | This lecture begins with a review of Aristotle’s metaphysical account of change and its implications for his teleological approach. Dr. Peikoff presents Aristotle’s argument for the Prime Mover and how it arises from the form/matter and potential/actual distinctions. Peikoff the presents Aristotle’s ethical system, beginning with his theory of the three types of soul, the concept of eudaimonia, the doctrine of the golden mean, and the role of pride. Peikoff offers some criticisms and analysis of Aristotle’s system before a brief consideration of his political writings. |
| Lecture 6 | Philosophy in the centuries following Aristotle became less systematic and original. Facing the changes in the Hellenistic period that witnessed the decline of the city-state and the rise of the Roman Empire, philosophers sought to answer how an individual could live in an uncertain world. This lecture examines the main schools of philosophy in this period: Epicureanism, Stoicism, Skepticism, and Neo-Platonism. Each school focused increasingly on the helplessness and incapacity of humanity and turned toward asceticism and otherworldly explanations of meaning and truth. |
| Lecture 7 | Emerging from the mystery religions of the Roman Empire and the Neo-Platonic philosophy of Plotinus, the rise of Christianity gained its first systematic philosopher in Saint Augustine. This lecture examines how Augustine systematized human dependence on God in all branches of philosophy. The resulting Dark Ages and early Middle Ages witnessed very little contributions to philosophy until the rediscovery of Aristotle in the West. The lecture concludes with an introduction to how Saint Thomas Aquinas built a philosophic system that combined Christianity with Aristotelianism. |
| Lecture 8 | This lecture explains the basis of Thomas Aquinas’s metaphysical system, his view of God, and how he also attempted to synthesize Aristotle and Christianity in his ethical system. It explores the consequences of Thomistic thought for later philosophy, especially as it influenced thinkers in the Renaissance and Protestant Reformation. The lecture concludes with an examination of how the rediscovery of antiquity and modern science, especially Francis Bacon and Galileo, influenced Renaissance thinkers. |
| Lecture 9 | The birth of modern philosophy is explored in the ideas of Thomas Hobbes and René Descartes. The materialist, empiricist, and nominalist approach of Hobbes influenced his metaphysical and epistemological views and led ultimately to his deterministic ethics and authoritarian politics. Descartes birthed the fully modern approach to philosophy with his method of doubt that leads to rationalism, his dualism in metaphysics, and his primacy of consciousness approach in epistemology. |
| Lecture 10 | The journey from rationalism to skepticism is explored in the philosophies of three followers of Descartes. Two rationalists, Spinoza and Leibniz, extended and completed the Cartesian project by presenting a more purely idealist metaphysics and rationalist epistemology. The reaction of the empiricist tradition reaches its height in John Locke’s epistemology and metaphysics, but which continued to separate reason from reality. |
| Lecture 11 | The tradition of British empiricism reaches its skeptical conclusion in the ideas of Bishop Berkeley and David Hume. Berkeley’s abandoning of any belief in the external world collapses into subjective idealism and a rejection of the senses. David Hume’s attack on reason in the name of reason leads to complete skepticism, denying the senses, causality, and any possibility of general ideas via induction. |
| Lecture 12 | This lecture explores the Objectivist answers to three of the main issues raised by the philosophers from Thales to Hume. First, the question of the validity of the evidence of senses is answered. Second, Dr. Peikoff explains how Objectivist epistemology solves the so-called problem of the borderline case introduced by nominalism. Finally, he explains the error of the Cartesian method of doubt. |
Modern Philosophy: Kant to the Present
| Lecture 1 | In this lecture, Dr. Peikoff provides an overview of the development of Western philosophy prior to the eighteenth century. He reviews the ideas of four major philosophers—Heraclitus, Plato, Aristotle, and David Hume—and how they each provided unique answers to some of the major questions in philosophy, specifically what is the nature of reality and how do we gain knowledge. |
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| Lecture 2 | Dr. Peikoff explores the thought of Immanuel Kant and his attempt to save philosophy from the skepticism of David Hume. He describes the Copernican Revolution implemented by Kant in proposing the innate structures of the human mind that shape all knowledge, and thereby cut us off from reality. Peikoff explains Kant’s main argument and its crucial distinctions between analytic and synthetic truths. |
| Lecture 3 | Continuing the discussion of Kant’s philosophic system, Dr. Peikoff explains how Kant used his Transcendental Deduction to prove the existence of the categories built into the human mind as well as the Metaphysical Deduction of the same. Peikoff also explicates the revolution in thought that Kant put forward to justify his duty-based ethical system. He concludes by showing how Kant claimed to connect the categorical imperative to God, Freedom, and Immortality. |
| Lecture 4 | The philosophy of Hegel represents the culmination of the attack on existence and identity. Dr. Peikoff explains how Hegel’s rejection of the Kantian noumenal world severed philosophy from its concern with existence apart from consciousness. He explains the theory of the dialectical nature of reality according to Hegel which ultimately leads to the coherence theory of truth. Peikoff explains the authoritarian political consequences of Hegel’s thought. He concludes with a series of objections and answers to Kant’s basic ideas. |
| Lecture 5 | The consequence of Kant and Hegel’s assault on reason was a wave of open irrationalism in German philosophy. Dr. Peikoff surveys the philosophic contributions of Schopenhauer, Nietzsche, and Marx. He explains the doctrine of metaphysical voluntarism and its worship of the will, leading both to Schopenhauer’s pessimism and Nietzsche’s worship of power and action. Peikoff also lays out Marx’s dialectical materialism and how it gave rise to his interpretation of human history and his support for communism. |
| Lecture 6 | In this lecture, Dr. Peikoff explores how three supposed defenders of science, Comte, Mill, and Spencer, ultimately worked to undermine it even further. He shows that the embrace of extreme nominalism produced Comte’s positivism and further undermined causality as well as supported his embrace of altruism in ethics and collectivism in politics. He concludes by highlighting how Mill’s utilitarianism and Spencer’s evolutionism both attempted to defend capitalism and failed. |
| Lecture 7 | This lecture explores the Pragmatist school of philosophy. Dr. Peikoff shows how the American pragmatists responded to elements in Descartes, Kant, and Hegel to produce their philosophy of practicality. In epistemology, the pragmatists’ theory of meaning led them to preach doing “whatever works” as an approach to truth. Peikoff illuminates how this approach led to subjectivism in both the individual and social varieties. |
| Lecture 8 | This lecture begins with an explanation of how the pragmatic theory of truth led to a subjectivist approach to ethics while showing that both areas of pragmatist thinking are parasitic and would completely lack content or values if applied from the ground up. In his discussion of Logical Positivism, Peikoff demonstrates how the acceptance of the analytic-synthetic dichotomy and a verifiability theory of meaning cut philosophy and logic off from reality. |
| Lecture 9 | Dr. Peikoff explores how the conclusions of the Logical Positivists produced the Analytic school of philosophy that argued that debating how people used ordinary language was the sum of philosophy. He explains how Moore, Russell, and Wittgenstein approached “language games” as cut off from facts and reality. He concludes by illustrating how this divorce of language from reality led to an emotive theory of ethics. |
| Lecture 10 | In this lecture, Dr. Peikoff explores the existentialist school of philosophy. Since Kant, philosophers had assumed that reality and reason were severed and prior schools chose reason and retreated from the world. Peikoff explores the thought of Dostoevsky, Kierkegaard, Heidegger, and Sartre in their embrace of existence and shunning of reason. He explains how these thinkers rejected reason and embraced existence but argued it must be known and navigated by a non-rational means. Further, he shows how, like Nietzsche, they embrace voluntarism and consider freedom to be unsettling but requiring action that is whim-driven. He concludes with a comparison to the rise of popularity of Zen Buddhism. |
| Lecture 11 | In this lecture, Dr. Peikoff presents the philosophy of Objectivism and its answers to some of the central questions in the history of philosophy. He highlights how its unique metaphysical starting point—the primacy of existence—helps orient the entire philosophy. He explains its implications for free will, the validity of the senses, and the nature of consciousness. Peikoff introduces the crucial distinction between the intrinsic, subjective, and objective. |
| Lecture 12 | Dr. Peikoff concludes his presentation of Objectivism’s answers to the major questions in the history of philosophy. He explains the theory of concept formation and contrasts it with previous theories, especially in relation to the theory of universals. He explains the metaphysical basis of concepts and how Objectivism understands the concept of certainty. Peikoff then derives and validates the principles of ethics in contrast to previous approaches. He concludes with a brief discussion of politics. |