Aristotle's concepts of potentiality and actuality are key to understanding change and reality. Potentiality refers to inherent capacities, while actuality is the realization of those capacities. These ideas help explain how things can change while maintaining their identity.

Aristotle uses potentiality and actuality to address fundamental philosophical problems. He reconciles being and becoming, explains how one substance can have many properties, and provides a framework for understanding the relationship between form and matter in change.

Aristotle's Metaphysics

Potentiality and actuality in Aristotle

• Potentiality (dunamis) refers to the capacity or possibility for something to change or become actual
  • An acorn has the potential to become an oak tree
  • Potentiality is not mere possibility, but a real power or capacity inherent in a thing
• Actuality (energeia or entelecheia) is the realization or fulfillment of a thing's potential
  • The grown oak tree is the actualization of the acorn's potential
  • Actuality is the end or goal towards which potentiality is directed
• Aristotle distinguishes between two types of potentiality:
  • Passive potentiality: the capacity to be affected or changed by something else (clay can be molded into a pot)
  • Active potentiality: the capacity to affect or change something else (a sculptor has the ability to mold clay)
• Actuality is prior to potentiality in three ways:
  • In definition: the definition of a potentiality depends on the corresponding actuality (the definition of "buildable" depends on the definition of "built")
  • In time: the actual exists before the potential in the sense that the actual is the end or goal of the potential (the adult exists before the child)
  • In substance: the actual is more real or substantial than the potential (the finished sculpture is more real than the raw materials)

Role in Aristotle's change theory

• Change, for Aristotle, is the process of a thing moving from potentiality to actuality
  • The process of an acorn growing into an oak tree is a change from potential to actual
  • A lump of bronze being sculpted into a statue is a change from potential form to actual form
• Aristotle identifies four causes that explain change:
  1. Material cause: the matter or substance out of which a thing is made (the bronze of a statue)
  2. Formal cause: the form, essence, or definition of a thing (the shape and features of the statue)
  3. Efficient cause: the agent or source of change (the sculptor chiseling the statue)
  4. Final cause: the end, purpose, or goal of the change (the completed statue)
• The efficient cause actualizes the potentiality of the material cause to take on the formal cause and achieve the final cause
• Aristotle distinguishes between two types of change:
  • Accidental change: a change in the accidental properties of a thing (a man growing a beard)
  • Substantial change: a change in the substance or essence of a thing (an acorn becoming an oak tree)
• In substantial change, the material cause (the acorn) has the potentiality to take on the formal cause (the form of an oak tree) through the agency of the efficient cause (the nutrients and sunlight) to achieve the final cause (the mature oak tree)

Applications of potentiality and actuality

• The problem of being and becoming:
  • Aristotle uses the concepts of potentiality and actuality to reconcile the Parmenidean idea of unchanging being with the Heraclitean idea of constant becoming
  • Being, for Aristotle, is not static but dynamic, as it involves the actualization of potentiality (a seed growing into a plant)
• The problem of the one and the many:
  • Potentiality and actuality help explain how a single substance can have multiple properties or undergo change while remaining the same substance
  • The substance (an acorn) remains one while its potentialities are actualized in many ways (growing roots, sprouting leaves, producing acorns)
• The problem of form and matter:
  • Potentiality is associated with matter, which is the substrate of change, while actuality is associated with form, which is the end or goal of change
  • The concepts of potentiality and actuality help explain how form and matter are related in the process of change (the potential of bronze to take on the form of a statue)
• The problem of teleology:
  • Aristotle's concept of final cause, which is the end or goal towards which a change is directed, is grounded in his theory of potentiality and actuality
  • The actualization of a thing's potentiality is directed towards its final cause or purpose (an acorn's potential is directed towards becoming a mature oak tree)