Aristotle’s Metaphysics is a work that delves into the fundamental principles of existence, reality, and knowledge. The seventh book of this monumental work discusses the concept of substance, which is one of the critical topics in Aristotle’s philosophy.

What is Substance?

Substance is a central concept in Aristotle’s metaphysics. In simple terms, substance refers to the underlying entity that defines an object’s identity.

For example, a chair’s substance would be the wood or material used to make it. Aristotle believed that substance was distinct from other attributes like color or shape since these could change without affecting an object’s identity.

Primary and Secondary Substances

Aristotle distinguished between primary and secondary substances. Primary substances are individual entities that exist independently.

They are concrete objects like people, animals, or objects in nature. On the other hand, secondary substances are abstract concepts like species or genera. For example, a lion is a primary substance while “animal” is a secondary substance.

What is the Nature of Substance?

Aristotle believed that substance was not just a physical entity but also had a metaphysical dimension. According to him, substance was composed of matter and form.

Matter refers to the physical stuff that makes up an object while form refers to its essential characteristics. He argued that it was impossible to separate matter and form since they were both necessary for an object’s existence.

The Four Causes

To fully understand substance, Aristotle proposed his theory of causation called the Four Causes – material cause, formal cause, efficient cause, and final cause. The material cause refers to the physical matter used in creating an object while the formal cause refers to its essential characteristics or form.

The efficient cause relates to how an object comes into being or what brings it about while final cause concerns its purpose or end goal. By understanding these four causes, one can understand the nature of substance and its relationship to other objects.

The Importance of Substance

Substance is a crucial concept in Aristotle’s philosophy because it defines an object’s identity and existence. It is the foundation of his metaphysics, and without it, his entire system would fall apart. Substance allows us to differentiate between things that exist independently and those that are merely abstract concepts.


In conclusion, substance is a fundamental concept in Aristotle’s Metaphysics. It refers to the underlying entity that defines an object’s identity and existence.

Aristotle believed that substance was both physical matter and metaphysical form and proposed his theory of causation – the Four Causes – to explain its nature. Understanding substance is crucial for understanding Aristotle’s philosophy as a whole, and it has far-reaching implications for how we perceive reality today.