Arthur Herman's The Cave and the Light: Plato Versus Aristotle, and the Struggle for the Soul of Western Civilization is an illuminating and thought-provoking look at how the theories of the two philosophers essentially shaped future civilizations. Here, he explains the two contrasting theories and, depending on which you subscribe to, what they say about you.

The ancient Greek philosophers Plato and Aristotle may seem like the quintessential Dead White Males, but in fact they’re very much alive. Twenty four centuries ago they laid the foundations of Western culture, and their ideas and insights still dictate essential features of our world right now, from what we eat to what we see on the Internet.

Forget right brain/ left brain: neuroscience debunked that theory years ago. And even forget Men From Mars and Women From Venus. The real split that shapes our lives, our relationships, and our culture is between our inner Plato and inner Aristotle.

Who were they?

Plato was a typical playboy from a wealthy, connected Athenian family until he met a man named Socrates, who taught him that the surest path to wisdom was rational contemplation, and that being a “lover of wisdom” or philosopher was the highest form of life.

Plato taught his students that all of us want to be part of something higher, a transcendent reality of which the world we see is only a small part, and which unites everything into a single harmonious whole. All of us, he said, want to crawl out of the cave of darkness and ignorance, and walk in the light of truth.

“There is no other road to happiness,” Plato concluded, “either for society or the individual.”

Plato’s most brilliant pupil, however, arrived at a very different view. Growing up in a family of Greek physicians, Aristotle learned early on the value of observation and hands-on experience. We don’t live in a cave, was his reply to Plato; we live in the real world. “Facts are the starting point” of all knowledge, Aristotle wrote. So instead of accepting his teacher’s belief in pure contemplation, Aristotle said our path to knowledge comes through logical, methodical discovery of the world around us–and the facts that make it up.

Aristotle asks: “How does it work?” Plato asks: “Why does it exist at all?”

Plato asks, “What do you want your world to be?” Aristotle asks, “How do you fit into the world that already exists?”

Plato asks, “What’s your dream?” Aristotle replies, “Wake up and smell the coffee.”

Two different world-views; one great debate. And here are five important lessons we can learn from both of them.

1. Twenty four hundred years ago Plato taught that every human soul has the desire to reach for a higher, purer, and more spiritual truth that will illuminate our lives and transform our world. That’s made him the chief spokesman for every religious mystic and every believer in a supernatural reality the West has ever produced, but also for poets, (whose works he said, “are not of man or human workmanship, but are divine and from the gods”), artists and musicians, not to mention lovers who are also soulmates (there’s a reason why it’s called Platonic love).

2. Aristotle, on the other hand, said the light of truth is found here in the material world, and our job is to understand and find our place in it. That made him the father of Western science (he wrote the first books on every field from biology and physics to astronomy and psychology) as well as technology, and the paragon of logical linear thinking, as opposed to Plato’s belief in the value of intuitive leaps of imagination.

3. The entire history of Western civilization has been the great struggle between these two ways of seeing the world, and that includes not just in every society but within ourselves: the constant tension between our inner Plato and inner Aristotle, our material and logical versus our spiritual and creative halves; that’s gets played out every day, in every way, in everything we do.

4. Today, Aristotle is the godfather of the Internet, entrepreneurial start-ups, and e-commerce: as he wrote in his Politics, the entire purpose of society is to enable each person “to attain a higher and better life by the mutual exchange of their different services.” Plato speaks instead to the environmentalist who wants to protect the planet; who sees the Big Picture and want to “think globally, act locally”--the bumper sticker Plato would most love.

5. Plato and Aristotle are important in personal relationships, too. Choosing the right mate or date can be as much about finding someone who balances our inner Plato or Aristotle, as it is about compatibility or shared interests--maybe more so. That’s true for my wife and me; we’ve been happily married for twenty-six years. She’s an artist and writer but her instincts are very Aristotelian, whereas I’m a self-confessed Platonist (although a secret Aristotle wannabe).

That works for us. Others might find that a pair of Platonists end up spending too much time contemplating the Eternal to get anything done, while two Aristotelians have a habit of falling into workaholic schedules.

So be forewarned. It was Aristotle who said, “To attain any assured knowledge about the soul is one of the most difficult things in the world.”

ARTHUR HERMAN, Pulitzer Prize Finalist and New York Times best-selling author of How The Scots Invented the Modern World, has just published his latest book, The Cave and the Light: Plato Versus Aristotle and the Struggle for the Soul of Western Civilization, with Random House.