Aristotle's Metaphysics: Substance, Reality, and Change

Aristotle's Concept of Substance and Reality

The reality, or substance, to which Aristotle alludes exists by itself; it is not inserted into anything else and therefore does not need anything else to be referred to. Unlike Plato, for whom these entities were ideas, for Aristotle, substance constitutes reality. The first things are the specific individuals.

Primary and Secondary Substances

We can ascribe attributes to individual beings, but these attributes do not exist sufficiently on their own; they do not exist if there were no specific individual beings to whom we predicate them. In summary:

• Individual beings are the primary substance because without them, there would be no world or nothing to speak of.
• Species (which apply to individual beings) are secondary substances because they cannot exist without individual beings to whom they apply.
• Accidents are not substances because individual beings can exist without them without ceasing to be what they are.

Aristotle's View on Nature

For Aristotle, sensible nature—the world we see and touch—is what he calls sensitive nature. This nature contains individual beings.

Matter and Form

Matter is the substratum of which a thing is made; it is the contour of a thing.

Form is how it functions; it determines what each individual being is and distinguishes one particular individual being from another, even if they share the same matter.

Types of Beings and Souls

There are four types of beings:

1. Inorganic beings
2. Plants
3. Animals
4. Human beings

There are three souls:

• The vegetative soul (governs food processing).
• The sensitive soul (gives rise to feelings and pleasure states).
• The rational soul (governs reasoning).

Soul, Body, and Change

The soul performs the vital functions of the body. Therefore, for Aristotle, there are no immortal and eternal souls separate from the body, as Plato believed. Soul and body are an inseparable compound in man; when a man loses his life, he loses both body and soul.

Potency and Act

Aristotle believed the soul itself is the structure of power and act, which explains how change occurs in nature.

Potency

The set of possibilities a thing holds. For example, a lion cub is the possibility of being a lion—a lion in potency. The potency of a thing is its ability to become something it is not yet.

Act

The process by which the possibilities of a thing come true. The act is what makes a lion cub actually become a lion.

Transition from Potency to Act

The transition from potency to act is change. In this change, a thing loses its material (preserving its form) and acquires a new form that it already possessed but was in potency.