Aristotle’s Metaphysics and Cosmology

Posted on Feb 10, 2025 in Philosophy and ethics

Aristotle’s Influences

Aristotle’s philosophy was significantly influenced by several predecessors:

  • Plato: While influenced by Plato’s concept of the universal soul as the principle of knowledge and his eudemonistic ethics, Aristotle diverged by asserting that the essence of things resides *within* the things themselves, not in a separate realm of Forms.
  • Parmenides: Aristotle adopted Parmenides’ concept of the universality and immutability of being, but he accounted for the multiplicity of being.
  • Heraclitus: Aristotle acknowledged Heraclitus’s concept of movement and change, but he provided a framework for understanding how things change while maintaining their identity.

Aristotle’s Theory of Reality

Aristotle differentiated types of knowledge:

  • Knowledge by experience.
  • Knowledge as a technique.
  • Knowledge as a way to prove or understand the ultimate causes of reality.

He posited that what is common to all things is that they exist *here and now* in a specific way. This he termed *Substance*. Aristotle identified three types of substances:

  1. Mutable, perishable, and material substances (studied by physics).
  2. Immutable substances, not separate from matter (studied by mathematics).
  3. Immutable, eternal substances, separate from matter (studied by metaphysics).

Critique of Plato’s Theory of Ideas

Aristotle criticized Plato’s Theory of Ideas for:

  • Duplicating reality without solving its problems.
  • Including inadmissible ideas (like beauty as an independent Form).
  • Failing to explain movement, as immutable Forms cannot account for change.

Aristotle argued that a thing and its essence are *not* separate. He explained reality through primary and secondary substances.

Sensible Reality consists of individual things and substances, which are inherently knowable. Physics, for Aristotle, explains that nature is the principle of movement because all things undergo transformations within themselves. These transformations include generation and corruption. Movement is the transition from one mode of being to another. He distinguished two types of change:

  • Substantial Change: Something ceases to be what it was and becomes something else, but the underlying subject remains.
  • Accidental Change: Changes in quantity, quality, or location; the substance remains, but its accidents change.

Hylomorphic Theory

Extracted from substantial change, the underlying principles of natural things are:

  • Matter: The underlying, simple raw material.
  • Form: That which brings necessary determinations, organization, physical structure, and a developmental plan.

Movement

Movement is the passage from *potency* to *act*:

  • Potency: The capacity to receive an act.
  • Act: The realization of potency.

The act is paramount in movement. Aristotle posited the existence of a *Prime Mover*, a pure act, to initiate all processes.

Aristotle identified four causes (two intrinsic and two extrinsic):

  • Material Cause: That of which something is made.
  • Formal Cause: The form acquired.
  • Efficient Cause: The agent that produces the process.
  • Final Cause: The intention of the agent.

These causes lead to two conclusions:

  1. The existence of an Unmoved Mover, as all movement is a succession of movers.
  2. The existence of a Pure Act, as otherwise, there would be an infinite succession of acts and potencies.

Cosmology

Aristotle’s cosmology is geocentric. He described the universe as a series of spheres:

  • Sublunar Sphere: Characterized by straight up-and-down movement due to gravity, composed of the four elements (earth, water, air, fire).
  • Translunar Sphere: Characterized by eternal, circular movement, composed of a different substance called *ether*.

Metaphysics (First Philosophy)

Metaphysics, or First Philosophy, aims at:

  • The study of being *qua* being.
  • The study of ultimate causes and principles.
  • The study of God.
  • The study of substance.

Being is not univocal but analogical (having many related ways of being):

  • Being as substance and as act.
  • Being as substance and accident.
  • Being as essence and accident.
  • Being as potency and act.
  • Being as true and untrue.

Being as substance and accident is the most important, as substance encompasses the other forms of being.