Aristotle's Metaphysics: Being, Substance, Causes

Aristotle's First Philosophy

The Study of Being

According to Aristotle's Metaphysics, all entities share something in common: being. Aristotle seeks knowledge that investigates ideas and principles valid for all types of entities, which he calls 'first philosophy'. The principles of being are present in all types of entities. These principles are not something sensible but are understood by precise reason.

Substance in Metaphysics

Defining Substance

The principle of substance is that which underlies an entity, ensuring it remains that specific being. Substance is always individual and not transferable. Substance is being, vital and fundamental. All that can be said of any entity must relate to its substance.

Types of Substance

Aristotle distinguishes three types of substance:

• Sensitive and corruptible (born and die)
• Sensitive but incorruptible
• Supersensible substance (eternal)

He describes God as pure act and the unmoved mover.

Aristotelian Categories

In any substance, one can distinguish modes of being called categories or principles derived from it. These include:

• Quantity
• Quality
• Relation
• Place
• Time
• Action
• Passion

There is no substance without categories, and no categories without a substance. Accidents are attributes that can be present or absent without affecting the substance; they can also change without affecting the substance.

Act and Potency

Act and potency are principles of being that explain how substances can achieve perfection that was previously missing. Act expresses the perfection of a being at a given time. Potency means that it has the capacity to be or become something. The transition from potency to act is what Aristotle defined as movement.

Matter and Form (Hylomorphism)

Being is composed of matter and form. Matter is conceived as the permanent substrate, the principle that explains how things change without being destroyed. Form is defined concretely and is inherent in the matter. If changes are accidental, the new form is also accidental. If the changes are substantial, a new substance is formed. This distinction between matter and form is called hylomorphism.

The Four Causes

There is no substance without a cause. Causes cannot be perceived by the senses but are understood by precise reason, accounting for each being. Aristotle identifies four causes:

• Efficient Cause: That which brings something into being.
• Formal Cause: Agrees with the form or essence of the thing; it is what makes a thing what it is.
• Material Cause: That out of which something is made; its material or structural elements.
• Final Cause: The purpose or end for which something exists or is done.

Nature and Essence

Nature is the synthesis of all these principles, defining a specific being. Essence is what a being has in common with others of its species.