Educating the mind without educating the heart is no education at all.

Aristotle (384 BC – 322 BC) was another of the key Greek philosophers and he was also a polymath. A student of Plato, Aristotle examined a diverse range of scientific and philosophical concepts, working on a branch of his own ethics.

A few things he’s said to have said:

It is the mark of an educated mind to be able to entertain a thought without accepting it.

Man is by nature a political animal.

The roots of education are bitter, but the fruit is sweet.

Happiness is the meaning and the purpose of life, the whole aim and end of human existence.

Aristotle is one of the most famous and influential philosophers and naturalists in history. A student of Plato, and later tutor to Alexander the Great. Aristotle was an empiricist focused on the A Posteriori routes to knowledge, that is, we gain knowledge by looking at the world and understanding it. Famously Aristotle worked out that an eclipse was caused by the moon moving between the Earth and the Sun or by the Earth itself moving in front of the Sun, and a shadow is cast across our field of vision. Therefore, the Earth must be spherical.

Aristotle topped another of this lister’s lists, heading the category of philosophy, so his rank on this one is not entirely surprising. But consider that Aristotle is the first to have written systems by which to understand and criticize everything from pure logic to ethics, politics, literature, even science. He theorized that there are four “causes”, or qualities, of any thing in existence: the material cause, which is what the subject is made of; the formal cause, or the arrangement of the subject’s material; the effective cause, the creator of the thing; and the final cause, which is the purpose for which a subject exists.

That all may sound perfectly obvious and not worth arguing over, but since it would take far too long for the purpose of a top ten list to expound on classical causality, suffice to say that all philosophers since Aristotle have had something to say on the matter, and absolutely everything that has been said, and perhaps can be said, is, or must be, based on Aristotle’s system of it: it is impossible to discuss causality without using or trying to debunk Aristotle’s ideas.

Aristotle is also the first person in Western history to argue that there is a hierarchy to all life in the Universe; that because Nature never did anything unnecessary as he observed, then in the same way, this animal is in charge of that animal, and likewise with plants and animals together. His so-called “ladder of life” has eleven rungs, at the top of which are humans. The Medieval Christian theorists ran with this idea, extrapolating it to the hierarchy of God with Man, including angels. Thus, the angelic hierarchy of Catholicism, usually thought as a purely Catholic notion, stems from Aristotle, who lived and died before Jesus was born. Aristotle was, in fact, at the very heart of the classical education system used through the Medieval western world.

Aristotle had something to say on just about every subject, whether abstract or concrete, and modern philosophy almost always bases every single principle, idea, notion or “discovery” on a teaching of Aristotle. His principles of ethics were founded on the concept of doing good, rather than merely being good. A person may be kind, merciful, charitable, etc., but until he proves this by helping others, his goodness means precisely nothing to the world, in which case it means nothing to himself. We could go on about Aristotle, of course, but this list has gone on long enough. Honorable mentions are very many, so list them as you like.

Aristotle is among the most important and influential thinkers and teachers in human history, often considered — alongside his mentor, Plato — to be a father of Western Philosophy.” Born in the northern part of ancient Greece, his writings and ideas on metaphysics, ethics, knowledge, and methodological inquiry are at the very root of human thought. Most philosophers who followed — both those who echoed and those who opposed his ideas — owed a direct debt to his wide-ranging influence. Aristotle’s enormous impact was a consequence both of the breadth of his writing and his personal reach during his lifetime.

In addition to being a philosopher, Aristotle was also a scientist, which led him to consider an enormous array of topics, and largely through the view that all concepts and knowledge are ultimately based on perception. A small sampling of topics covered in Aristotle’s writing includes physics, biology, psychology, linguistics, logic, ethics, rhetoric, politics, government, music, theatre, poetry, and metaphysics. He was also in a unique position to prevail directly over thinking throughout the known world, tutoring a young Alexander the Great at the request of the future conqueror’s father, Phillip II of Macedon. This position of influence gave Aristotle the means to establish the library at Lyceum, where he produced hundreds of writings on papyrus scrolls. And of course, it also gave him direct sway over the mind of a man who would one day command an empire stretching from Greece to northwestern India. The result was an enormous sphere of influence for Aristotle’s ideas, one that only began to be challenged by Renaissance thinkers nearly 2,000 years later.

Aristotle’s Big Ideas

  • Asserted the use of logic as a method of argument and offered the basic methodological template for analytical discourse;
  • Espoused the understanding that knowledge is built from the study of things that happen in the world, and that some knowledge is universal — a prevailing set of ideas throughout Western Civilization thereafter;
  • Defined metaphysics as “the knowledge of immaterial being,” and used this framework to examine the relationship between substance (a combination of matter and form) and essence, from which he devises that man is comprised from a unity of the two.

Aristotle’s Key Works

  • The Metaphysics
  • Ethics
  • Poetics

Aristotle can be considered the world’s first natural historian.

Simon Worrall(2014) National Geographic

Aristotle (384-322 BC) Ancient Greek philosopher and scientist. Aristotle as a young man in his study. Artist's reconstruction: wood engraving c1886
Let’s have a think my dear sweetheart

WHAT IS LIFE? What is a soul? These are some of the questions Greek philosopher Aristotle asked. And we’re still asking them today.

Aristotle also could be considered the world’s first natural historian. Acclaimed biologist Armand Marie Leroi, in his new book, The Lagoon: How Aristotle Invented Science, follows in Aristotle’s footsteps to the Greek island of Lesbos, where Aristotle—the man Plato called “the foal”—did much of his hands-on research.

Speaking from his home in London, the author describes how a chance encounter in an Athens bookshop led him on a journey of discovery, why it’s important to get your hands dirty if you want to understand the world, and why, among other things, Aristotle thought blondes have the best orgasms.

Your book begins with a childhood memory. Take us back there.

When I was 11 or so, I became interested in seashells. I was living in South Africa at the time, and I discovered in the garage an old flight bag full of seashells, which my parents had picked up. It became a nucleus of a shell collection. There was one shell in particular, which my parents had bought on their honeymoon in the Mediterranean. It was a trumpet shell, a very beautiful thing, and I pinched that too [Laughs]. I was going to be the world’s most famous malacologist: a snail biologist. I never became a malacologist. But I did become a biologist. And that’s where it began.

Thirty years later, long after I’d put away my shells, I walked into a bookshop in Athens and discovered a book called Historia Animalium, by Aristotle. I wasn’t at all interested in Aristotle or philosophy. I was a biologist. But the title attracted me. So I took it down and started reading. There was Aristotle, this guy who had died 2,300 years ago, describing my shell. And I understood exactly what he was saying.

You imagine at one point Aristotle “breakfasting on figs and honey.” What do we know about Aristotle, the man?

Remarkably little. Aristotle leaves behind several thousand pages of work, but none of it autobiographical. What we have in terms of autobiography is hearsay—stories related by later philosophers, typically written several centuries after his death. You can try to winnow out some truth from them but it’s very hard because they often come from competing philosophical schools, and so they’re notoriously unreliable.

We do have a description of him, and it’s not a very attractive one. He’s got bandy legs and small eyes. He also seems to have been a bit of a dandy, who fussed around with his hair. But once again it’s not clear whether this is an accurate description—or a hostile one. It’s certainly written by someone several centuries after Aristotle died, in 322 B.C.

The most immediate document we have is a reproduction of his will. Here we have a sense of Aristotle, the man. He speaks, for example, of how he’d like to be buried next to Pythias, his first wife, because that’s what she would have wanted. She was young when Aristotle married her—he was around the age of 37. So we have a sense that he loved her very much.

An illustration of Aristotle.
Both Plato and Aristotle taught at an academy in Piraeus, the port area of Athens.
You give a wonderful description of the academy in ancient Athens where Aristotle and Plato lectured. Give us a virtual tour.

The academy was in Piraeus, the port area of Athens. There’s not much left of it now, just some rocks and a dusty field with some trees. In its day it was something like a philosophical club. Not a university but a group of friends, with some sort of hierarchy. Clearly, Plato is at the top. There are other, young teachers sitting about, arguing and quarreling, but in a friendly spirit.

What makes Plato’s academy special is that although it seems to be one of several different schools in Athens, Plato didn’t charge for admission. He’s reasonably well off, and it’s clear that the academy is infused with his purpose, which is the pursuit of philosophical truth. The schools that the Sophists ran were all about teaching young men how to speak well, and get on in life. In modern parlance, you went to Plato for a Ph.D. and to the Sophists for an MBA.

There was lots of competition between Plato and Aristotle, wasn’t there?

There’s quite a bit of competition. Aristotle is 17 years old when he comes to the academy. It’s clear he must be very bright because he quickly becomes known as “the reader.” Sometimes he’s also called the brains of the school.

Later on, as Aristotle gets older and more confident, Plato refers to him as the foal, by which he means Aristotle kicks his mother, as a foal kicks his dam. In other words, he’s an ungrateful recipient of the good things his forebears were giving him.

Disputes were inevitable. We have two of the greatest thinkers of all time right next to each other, and they will turn out to have very different views of the world, even though their views are also deeply intertwined, as pupil and teacher must be. When Plato dies, Aristotle is 37, and right around then he leaves the academy and strikes out on his own.

This is a scholarly work. It’s also a travelogue and a memoir. Tell us about the lagoon.

When we imagine a typical Greek island, like in the Cyclades, we think of a bare rock with some whitewashed houses on it. Lesbos is not like that. It’s a large, ramshackle, agricultural island. Half of it is quite dry, half of it is wonderfully forested, with rivers and meadows and wildflowers. It’s also a resting place for millions of migratory birds that go between Africa and the north every year. So there’s lots of nature.

Bisecting this beautiful island is a lagoon 13 miles long, 6 miles wide, and 30 feet deep. It turns out to be one of the richest bodies of water in the Aegean, the nursery ground for the local fish. There are sardines and cuttlefish—all the creatures Aristotle describes. We have no definitive proof, but it seems likely that his descriptions of the lagoon are the oldest descriptions of any natural place in the world.

If you go down to the lagoon today, you’ll see a series of little fishing villages. Some of them were bigger in Aristotle’s time. They use little boats called trehantiri. In Aristotle’s time they would have had sails instead of motors. But the designs aren’t terribly different, and the techniques by which they fished aren’t very different. For example, every year the fishermen throw bundles of branches into the water for the cuttlefish to lay their eggs on to ensure a good crop the following year. And this is exactly what Aristotle described 23 centuries ago!

An illustration of Aristotle.
Aristotle did much of his research about the natural world on the Greek island of Lesbos.
Aristotle described about 500 creatures in his immediate environment. He also described animals he could not have seen, like the elephant and the lion. How did he get his information?

Aristotle never left the Aegean, but he describes a lot of exotica, like African and Asian animals. How did he know all this? There’s a wonderful story by Pliny—that Alexander the Great ordered all the commanders in his army, throughout Asia Minor, to send Aristotle specimens of the creatures they encountered. Why would he do this? Because Aristotle taught the young Macedon prince who would go on to become Alexander the Great. According to Pliny, this is the homage of the young general to his much-loved teacher.

It’s a wonderful story. And I think it’s almost certainly a myth, because so much of what Aristotle says about exotic creatures is dodgy. When he talks about Greek animals—a cuttlefish, for example—he speaks about them in such detail and with such accuracy that you get a sense that he actually saw the thing, and even cut it up. He did a lot of dissection.

But as soon as he starts talking about exotica, it all becomes much vaguer. He knows a lot about elephants, but he thinks they’re semiaquatic. That’s not entirely wrong. Elephants do like mucking about in water. But he’s unsure as to how bendy their legs are. That later gave rise to a myth that elephants couldn’t bend their legs and slept upright.

As well as following in Aristotle’s footsteps, you did lots of hands-on research, observing and even dissecting the creatures Aristotle studied. Tell us about the soul of a cuttlefish.

[Laughs] So what is the soul of the cuttlefish? The first thing that’s remarkable about Aristotle is that you can take a cuttlefish from the lagoon and pretty much dissect it following his instructions. I did this myself. It’s the only way to see what he’s doing.

If I’ve made any contribution toward the study of Aristotle, it’s in doing things like this. Philosophers love to study these things in the privacy of their studies or libraries. Many of them don’t even bother to go to Greece let alone look at the cuttlefish Aristotle describes. They know their Aristotle, they know their Greek—bless them. But you have to wonder: Don’t you think you should go out and get your hands a bit dirty, in order to see what he was actually looking at?

You’re an evolutionary biologist. Aristotle also explored evolution. To what extent did he prefigure Darwin?

He prefigures Darwin in many different ways, except the one way that really matters. That is to say, he doesn’t get to evolution. I know that sounds paradoxical. Like Darwin, he looks at the world like an architect or an engineer. He looks at biological creatures and asks: What are they for, and what are their parts for? For example, he analyzes the diversity of birds—their beaks, their legs, and so on, in terms of their function and their fitness to the environment. What we would now call adaptations.

But Aristotle is not an evolutionist. He’s not a creationist, either. He’s something very much stranger: an eternalist. According to Aristotle, the world is a perfectly engineered system, in which creatures are fitted to their environment and fitted to each other. How did the system originate? Aristotle says that’s the wrong question. It’s always been there. It’s a very strange idea for us today, because our entire worldview is conditioned by the opposition between creationism and evolutionism.

An illustration of Aristotle.
Aristotle described hundreds of animals, including those he could not have seen—such as the elephant and lion.
He also wrote extensively about sex, both animal and human, including the female orgasm. What was his view?

He doesn’t have a technical word for orgasm. But it’s very clear what he’s talking about. And he’s very clear that women have pleasure in intercourse. Extreme pleasure. Pleasure equivalent to that of a man’s. Blondes get particularly aroused, he says. And Aristotle thinks this is a good thing.

The only question he’s got is whether [intercourse] is absolutely necessary in order to conceive. He has this elaborate theory about female fluids and reproduction. He spent a lot of time trying to separate out female fluids: menstrual fluids from vaginal lubrication from urine from female ejaculation. It all gets terribly complicated.

You write that Aristotle confronted the biggest of all questions: What is life? How did he answer?

Life is a thing that has a soul. All living things have souls. Dead things do not. Inanimate things do not. That sounds mystical because we’re conditioned to think about the soul, in the Judeo-Christian tradition, as some immaterial entity that survives us when we die. Aristotle’s predecessors, like Plato, had a conception of the soul not unlike that. They thought that the soul is something unique to humans, and immortal.

Aristotle says this is nonsense. The soul should be conceived of as the thing that animates all living things, all plants and animals. When a creature dies, its soul dies too. The soul is part of the system that maintains the creature’s life.

That concept runs throughout the history of biology but in many ways is only now receiving its full fruition. Twentieth-century science was all about taking creatures apart, reducing them down to their cells, molecules, and genes. Twenty-first century science is all about putting them back together again.

That is Aristotle’s great insight. He says it’s fine to understand things in parts, and he devotes a lot of time doing so … Sometimes he’s right. Sometimes he’s wrong. But his big idea is that you have to put it all together again.

That’s why I say he’s the very first systems biologist—and why finally, in the 21st century, when we ourselves have begun to put systems together, we can see more clearly what he was up to than ever before.

You end the book back at the lagoon with a declaration of love and admiration for Aristotle. What do you revere most?

His courage. Aristotle is the first person, as far as we can tell, to go down to the shore, pick up a snail, look inside, and ask what’s there. He’s the first person to take all this despised, squishy stuff—the stuff of the butcher, or the fishmonger, as well as our physiological processes, in all their grossness—and say: These things may disgust us, but they shouldn’t, because there’s something beautiful here too. And that takes courage. It’s that boldness of conception to open up the study of a new world, but one that was in front of us all that time. That’s what I love about him.

What is a friend? A single soul dwelling in two bodies.