Aristotle was a firm believer in metaphysics. He referred to it as the “first philosophy,” and in many regards, metaphysics is the foundation of all philosophies. Metaphysics focuses on the nature of being and existence, and asks very complicated and profound questions relating to God, our existence, if there is a world outside of the mind, and what reality is.

Originally, Aristotle broke metaphysics up into three branches, which continue to be the major branches of metaphysics to this day. They are:

1. Ontology: The study of existence and being, including mental and physical entities, and the study of change.
2. Universal Science: The study of logic and reasoning, considered to be the “first principles.”
3. Natural Theology: The study of God, religion, spirituality, and creation.

EXISTENCE EXISTS

In metaphysics, existence is defined as a state of continued being. “Existence exists” is the famous axiom to come out of metaphysics; it simply states that there is something instead of nothing. The root of every thought a person ever has is the notion that he is aware of something, which is proof that something must exist. Therefore, if something must exist, that must mean that existence has to exist.

Existence is necessary and required for there to be any type of knowledge.

When one denies the existence of something, he is saying that something does not exist. However, even the very act of denying can only be possible if existence exists. In order for anything to exist, it must have an identity. Everything that exists exists as something, for otherwise it would be nothing and would not exist.

In order for one to have a thought of being aware of something, one has to be conscious. Therefore, according to René Descartes, consciousness has to exist because one cannot deny the existence of his mind while using his mind to make that denial. However, Descartes’s axiom was incorrect because he believed a person has the ability to be aware without there being something to be aware of. This cannot be the case, however.

Consciousness, rather, is the faculty to perceive what exists. Being conscious means one is perceiving something, so to function, consciousness requires that there be something outside of itself. Therefore, consciousness not only requires existence; it is also dependent upon existence. Descartes’s axiom of consciousness as being aware of being conscious cannot, therefore, be the case because to be conscious requires the existence of something external.

OBJECTS AND PROPERTIES

In metaphysics, philosophers try to understand the nature of objects and the properties of these objects. According to metaphysics, the world is made up of things, known as objects or particulars, that can be either physical or abstract. These particulars share certain qualities or attributes in common with one another, and philosophers refer to these commonalities as universals or properties.

When philosophers attempt to explain whether properties can exist in more than one place simultaneously, they run across what is referred to as the “problem of universals.” For example, a red apple and a red car can exist simultaneously, so is there some kind of property that exists that is “redness”? If redness does exist, what is it? Different schools of thought answer that question in their own ways:

• According to Platonic realism, redness does exist, but it exists outside of space and time.
• According to moderate forms of realism, redness exists within space and time.
• According to nominalism, universals like redness do not exist independently; they exist as names alone.

These ideas of existence and properties lead to one of the most important aspects of metaphysics: identity.

IDENTITY

In metaphysics, identity is defined as whatever makes an entity recognizable. All entities have specific characteristics and qualities that allow one to define and distinguish them from other entities. As Aristotle states in his law of identity, in order to exist, an entity must have a particular identity.

In discussing what the identity of an entity is, two very important concepts arise: change and causality.

Many identities can appear to be unstable. Houses can fall apart; eggs can break; plants can die; etc. However, these identities are not unstable; these objects are simply being affected by causality and are changing based on their identities. Therefore, identity needs to be explained based on the entity’s building blocks and how those interact with one another. In other words, the identity of an entity is the sum of its parts. One can describe a house by describing how the different parts of wood, glass, and metal interact with one another in a specific way to form the house, or one can define a house’s identity based on its formation of atoms.

To alter an identity, a change (caused by an action) needs to occur. The law of causality states that all causes have specific effects that are dependent on the original identities of the entities.

Currently, three main theories discuss the issue of change:

1. Perdurantism: This is the notion that objects are four- dimensional. According to perdurantism, objects have temporal parts (parts that exist in time), and at every moment of existence, objects only partly exist. So for example, there would be a series of stages for the life of a tree.
2. Endurantism: This is the notion that objects are the same and whole throughout every moment of the objects’ history. So for example, as a tree loses leaves, it is still considered to be the same tree.

3. Mereological Essentialism: This notion explains that parts of an object are essential to that object. Therefore, the object is not able to persist if any of its parts change. According to mereological essentialism, when a tree loses its leaves, it is no longer the same tree. Because metaphysics touches on our existence and what it truly means to be in the world, it touches on a wide variety of philosophical issues. And it is for this very reason that metaphysics is often considered to be the foundation of philosophy, or “first philosophy.”