What is our species' greatest invention? Medicine, computers, space travel? Not even close. The innovation that underlies each of our past achievements and those we still aspire to is language. Language is the ultimate invention of Homo sapiens - one that has allowed us to change the physical and social world around us in every conceivable way, and an invention that has fundamentally changed us, as well.

Delve into the exciting field of “epistemology”, the philosophical term for our inquiry into knowledge: what it is, the ways we acquire it, and how we justify our beliefs as knowledge. Taught by acclaimed Professor Joseph H. Shieber of Lafayette College, these 24 mind-bending lectures take you from ancient philosophers to contemporary neurobiologists, and from wide-ranging social networks to the deepest recesses of your own brain.

Language defines us as a species, placing humans head and shoulders above even the most proficient animal communicators. But it also beguiles us with its endless mysteries, allowing us to ponder why different languages emerged, why there isn't simply a single language, how languages change over time and whether that's good or bad, and how languages die out and become extinct.

What is life? What is my place in it? What choices do these questions obligate me to make? More than a half-century after it burst upon the intellectual scene - with roots that extend to the mid-19th century - Existentialism's quest to answer these most fundamental questions of individual responsibility, morality, and personal freedom, life has continued to exert a profound attraction.

The history of the Constitution is therefore a history of ideas that define our country and our national identity—and it’s a fascinating and revealing story. The US Constitution Through History gives you the opportunity to explore the story of this powerful document, as well as the way our interpretation of it has evolved. In 24 riveting lectures, Professor Eric Berger of the University of Nebraska takes you on a journey through America’s constitutional history. He takes you inside the minds of the Framers and unpacks the ideas that led to the break from England.

From spirituality to politics and science, the occult has had an astonishing influence on the human experience across the centuries. It may surprise you to learn that everyday activities like attending church services or reading your daily horoscope all fit the broad definition of the occult. As you will see in the 24 illuminating episodes of Secrets of the Occult, the mystic and obscure are threaded through our ordinary lives in more ways than you may realize.

"It doesn't take an Einstein to understand modern physics," says Professor Wolfson at the outset of these 24 lectures on what may be the most important subjects in the universe: relativity and quantum physics. Both have reputations for complexity. But the basic ideas behind them are, in fact, simple and comprehensible by anyone. These dynamic and illuminating lectures begin with a brief overview of theories of physical reality starting with Aristotle and culminating in Newtonian or "classical" physics.

These 12 illuminating lectures paint a rich and detailed portrait of the life, works, and ideas of this remarkable figure, whose own search for God has profoundly shaped all of Western Christianity. You'll learn what Augustine taught and why he taught it – and how those teachings and doctrines helped shape the Roman Catholic Church. These lectures are rewarding even if you have no background at all in classical philosophy or Christian theology.

Grasp the important ideas that have served as the backbone of philosophy across the ages with this extraordinary 60-lecture series. This is your opportunity to explore the enormous range of philosophical perspectives and ponder the most important and enduring of human questions-without spending your life poring over dense philosophical texts.

In this course, Prof. Anthony Esolen will examine ancient Mesopotamia, Greece, Rome and Israel, seeing the disappointment and Messianic longing in the pagan Roman poet Virgil, and the fulfilled Messianic longing among the prophets and the inspired authors of the Old Testament. You will discover the ways in which the fulfillment of the person of Jesus Christ never ceases to surprise mankind, because it never ceases to contradict what fallen man accepts as great.