Detail of Plato on the left and Aristotle on the right, School of Athens.

Who Was Aristotle?

Every discipline has its stars. For mathematics, it's Pythagoras; for physics, Einstein and Newton; and for philosophy, it's Aristotle. Considered one of the best philosophers of all time, Aristotle is only matched in terms of philosophical influence by his teacher Plato. His work was original, and groundbreaking. Today, Aristotle's philosophy is the foundation of Western Scholasticism. Aristotle's work has shaped the entire discipline of philosophy. He left as many as two hundred works, with around 31 surviving today. The works of Aristotle span across almost every discipline of philosophy and even disciplines outside of philosophy, such as biology. His work in ethics inspired the field of virtue ethics, an approach to ethics that emphasizes the importance of character.

Aristotle believed being a good person and a good citizen were different. He famously writes in Nichomean Ethics, "It is not always the same thing to be a good man and a good citizen." This changed what people believed about politics.

Throughout his life, Aristotle had associations with other prominent figures of his time. When Aristotle was older, he even tutored Alexander the Great. Delve into the life of Aristotle and discover some of his most important philosophies.

Early Life And Education

Detail of the right-hand facade fresco, showing Aristotle and His Disciples. National and Kapodistrian University of Athens.
Aristotle and his disciples, National and Kapodistrian University of Athens.

Aristotle was born in the small Greek city of Stagira in 384 BC. Aristotle's name means "the best purpose." In terms of his contribution to philosophy, Aristotle lived up to this name. Little information is available about Aristotle's childhood besides the fact that he spent a lot of time in the Macedonian palace. His family had connections with the Macedonian monarchy because his father was the King's doctor.

Aristotle's father's scientific work inspired Aristotle to study. While Aristotle was not inspired to study medicine, he was a dedicated student. At 17, Aristotle went to Plato's academy in Athens, where he spent the next 20 years.

Aristotle has writings from this period, but few survived. Plato's writing style influenced Aristotle's early writing. Originally, Aristotle wrote in dialogue form, similar to Plato. At this time, Aristotle mirrored more of Plato's philosophy. One of Aristotle's works that shows this is his dialogue Eudemus. This dialogue reflects Plato's view that death liberates the soul from the body to be happier. In Aristotle's view, the soul is stuck in the body, and the soul can only attain a happier life once it has left the body behind.

Aristotle Leaving Athens

Statue of Aristotle a great greek philosopher
Statue of Aristotle, a great Greek philosopher.

The exact reason Aristotle left Athens is unclear. Traditional stories paint Aristotle as expressing dissent with the direction the academy was going. Plato's nephew Speusippus overtook The Academy, and Aristotle disagreed with him. However, there are rumors that Aristotle moved before Plato's nephew overtook the academy. He feared anti-Macedonian sentiments at the time, and some people believe he moved to the court of his friend Hermias of Atarneus in Asia Minor, where he then traveled to the island of Lesbos. On the island, Aristotle did an in-depth biological analysis of plants and animals, along with Theophrastus.

Aristotle Distancing Himself From Plato

Marvel at the intricate low relief sculpture depicting Plato and Aristotle arguing by Andrea Pisano (14th Century) adorning the external wall of Florence Cathedral.
Low relief sculpture depicting Plato and Aristotle arguing by Andrea Pisano (14th Century) adorning the external wall of Florence Cathedral. Image credit Krikkiat via Shutterstock

Aristotle's works, although heavily influenced by Plato, were very different in certain aspects. One big difference between Aristotle and Plato is their different views on Forms. Aristotle disagreed with Plato's theory of Forms.  According to Plato, there are ideal versions of items separate from the actual item. For example, there is an ideal form of friendship and justice. This, in Plato's view, gives you an idea of what we should strive for in reality. For example, the ideal form of friendship tells you what a friend should be. These ideals, Plato referred to as forms. He also applied this idea to more concrete objects, such as cats and mud. However, Plato was unsure if concrete forms of ordinary objects like this existed.

Aristotle criticized Plato's theory as being too abstract and not rooted in reality. Unlike Plato, Aristotle believed the form of the object was the material form and not an abstract idea. He also didn't see forms as independent from reality like Plato did.

Aristotle's Works

Illustration of Aristotle's works on Ethics.
Illustration of Aristotle's works on Ethics.

In his entire life, Aristotle wrote an estimated 200 works. Today, only 31 have survived. Some of Aristotle's most well-known works include Poetics, Metaphysics, Politics, Physics, De Anima, and Nicomachean Ethics. Aristotle's works are in four categories. The Oranon works refer to the writings Aristotle has on logic and philosophy or scientific studies. The next grouping of Aristotle's works is his theoretical work. This encompasses a range of topics, including his work on observing animals, cosmology, Physics, and Metaphysics.

The third grouping of Aristotle's works is his work in ethics and politics. The final body of his work is his Rhetoric and Poetics. These works look at the creation of human products. Aristotle's Poetics is in two books. One is a tragedy, and the other is a comedy. Some believe his works are lecture notes that he used at his school.

Aristotelian Philosophy

Close up rendition of Aristotle
Depiction of Aristotle.

Substance Theory

Substance Theory was one of Aristotle's most important philosophies. Aristotle's other works relied on the tenets of this philosophy. Substance theory states that substances make up the universe instead of elementary particles. In this view, substances are both matter and form. Matter is the physicality of the substance, whereas form refers to the definitive characteristics of a substance. This idea applies to both physical substances, such as trees, and abstract substances, such as justice. For abstract substances such as justice, Aristotle said that individual cases made up the matter of the substance, and the universal idea of justice made up the form.

The theory was further broken down into essential properties and accidental properties. Essential properties of a substance were properties seen as essential to a substance's existence. For example, in the case of a tree, a tree being a living organism would be an essential property. Without this property, the tree would not exist. Accidental properties, on the other hand, are properties that are not essential to the substance's existence. For example, the color and height of a tree are accidental properties. If the color or height of the tree changed, it would not have an impact on the existence of the tree.

Aristotle's substance theory emphasized the importance of the underlying nature of things. It was also groundbreaking in distinguishing material and immaterial elements. Some critics argue that Aristotle's substance theory is too vague and abstract.


Aristotle's book, Nichomean Ethics, outlines his philosophy on ethics. As a result of his contributions to philosophy, a major branch of ethics was named after him, Aristotelian ethics. In Aristotle's ethics, he aims to answer two questions above all else. Firstly, what does it mean to live a good life? And second, what qualities should a person have to flourish and live a good life?

In Nichomean ethics, Aristotle outlines the idea that the goal of human life is happiness. According to Aristotle, happiness is not an external goal reached through achieving higher status, wealth, or material goods. Rather, your soul has to be in line with virtue for you to be happy. Aristotle outlines four virtues he believes to be the most important: wisdom, courage, justice, and self-control.

A unique idea mentioned in Aristotle's writing on ethics is the idea of the Golden Mean. This is the idea that for each value, there is a balance to embody it. Someone should aim to act on a value between excess and deficiency in their actions. For example, when embodying courage, someone needs to be courageous enough to act but not overly courageous. If the person is being too courageous, they might be acting without fear and rationality, which can lead to poor decision-making.

Aristotle also talked about the idea of eudaimonia in his writing on ethics. This is what he called human flourishment, and people achieve eudaimonia by living with virtue.

Logic and Knowledge

Aristotle's works grouped together with the title Organon are his works on logic. These include Categories, On Interpretation, Prior Analytics, Posterior Analytics, Topics, and On Sophistical Refutations. As the expert of logic at his time, his work in logic was extensive. Immanuel Kant famously said that Aristotle had discovered everything there was to discover about logic. Today, we know this is not the case, as other people have made significant contributions to the field of philosophy.

The foundation of Aristotle's theory of knowledge was a version of empiricism. This is the idea that we gain knowledge through our senses and experience. Aristotle did not invent the idea of empiricism. Protagoras, a previous philosopher, held a similar idea. Aristotle also discussed how to gather information from objects through deduction and inferences. Modern philosophers shaped Aristotle's theory of deduction into "Syllogism."


Aristotle's work titled Politics talked about life in a city. According to Aristotle, a city is a natural community, proving that humans are political animals by nature. There is an overlap between Aristotle's work on ethics and his political work. One of Aristotle's famous quotes about politics is from Nichomean ethics. He states, "It is not always the same thing to be a good man and a good citizen."

Here, Aristotle is talking about how being a good citizen is a separate endeavor from being a good person. Being a good citizen will change depending on the city you are living in. Being a good citizen and a good person is only the same in Aristotle's view when an individual is living in their ideal city. This means when the individual is living in their nonideal city, the two are distinct entities. A deduction from this is that there may be times when being a good citizen demands acting contrary to being a good person. However, Aristotle never really delves into these situations.

Contributions to Science

Beyond philosophy, Aristotle made important contributions to the sciences. Specifically biology. While he wouldn't be a scientist by the standards of today, he extensively researched and studied many lifeforms and objects. He believed studying physical objects was important in the pursuit of knowledge.

Aristotle's focus in biology was on classifying animals into species. He classified animals on the basis of blood. Animals with red blood were mostly vertebrate animals, and other animals that were bloodless were cephalopods. Aristotle also looked at marine life through dissection. His biological hypothesis is inaccurate today, but at the time, it was revolutionary and used as the standard system.

Relationship With Alexander The Great

Olympias presenting the young Alexander the Great to Aristotle by Gerard Hoet before 1733
Olympias presenting the young Alexander the Great to Aristotle by Gerard Hoet.

In 343 BC, Philip II of Macedon asked Aristotle to tutor his son, Alexander, after the death of Hermias. Aristotle left Lesbos and moved to Pella, the Macedonian capital. There, he tutored 13-year-old Alexander. There is little information on the content of Aristotle's instruction to Alexander. While Rhetoric to Alexander was previously included in Aristotle's works and was useful in understanding their relationship, today, people believe it is a forgery.

Alexander's tuition would have only lasted two or three years with Aristotle, when Alexander was 13 to 15. By the age of 15, Alexander was serving as a deputy military commander for his father. This ended his period of tutoring from Aristotle. By 326 BC, Alexander was the ruler of a massive empire stretching from the Danube to the Indus. During Alexander's campaign, he did maintain some contact with Aristotle. According to some reports, Alexander sent Aristotle some biological specimens to study.

When Alexander died in 323 BC, Athens was democratic, and the city was unhospitable for Macedonians, even if they were anti-imperialists. In fear, Aristotle fled the city to Chalcis, where he died the next year.

The Lyceum

Athens, Greece. November 2021. panoramic view of the archaeological excavations of Aristotle's Lyceum in the city center
Athens, Greece, view of the archaeological excavations of Aristotle's Lyceum in the city center. Image credit Sergio Delle Vedove via Shutterstock

During his life, Aristotle opened his own school called the Lyceum. The school was set up in a gymnasium when Alexander was conquering Asia. Aristotle built a library and had a dedicated group of research students. Unlike Plato's academy, the Lyceym's lectures were open to the public, free of charge.

The Lyceum was an astonishing accomplishment at its time. Aristotle made reading the writing of others an important part of the philosophical process, and as a result, the Lyceum assembled a huge collection of manuscripts. It was one of the world's first great libraries. After Aristotle's death, his school continued on for some period of time. However, it is unknown exactly how long it continued.

Aristotle's Legacy

Aristotle's teachings had a profound impact on his students. Many went on to combine Aristotle's philosophy with ideas of their own. One of the most famous and controversial is Thomas Aquinas. Thomas Aquinas reconciled Aristotle's philosophy with Christian thought and made Aristotelian philosophy the framework for Christian philosophy from the 12th to the 16th century.

Today, Aristotle is a philosopher famous in his discipline. Many modern philosophers continue to look at Aristotle's work for guidance and inspiration. His work is, in many ways, is the backbone of Western philosophy. While Aristotle is a philosopher from another time, there is still a lot of insight modern thinkers can gain from looking at his work.


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