Philosophical Foundations: Aristotle, Descartes, and Locke

Aristotle

Aristotle, a pupil of Plato, spent twenty years at the Academy. He excelled in all areas of knowledge, providing insights that greatly influenced later thought. How can we explain the essence of a particular man with an unchanging, external idea of man? Aristotle proposed a different conception of being: a red apple exists differently than the apple itself. The apple seems more consistent as an independent entity, while the red depends on the apple’s existence. This is Aristotle’s analogy of being, stating that being is understood in different ways. Faced with permanence and change, Aristotle argues that every being has something that changes and something that remains the same. A poplar seed grows into a rod and then a tree, remaining the same despite changes. Substance is “what exists in itself,” the individual with its own existence (e.g., the poplar). When a substance changes without losing its identity, it changes in its accidents (color, size). Substantial change occurs when a substance’s identity is lost, leading to destruction and generation. Metaphysics or ontology, the science of being, focuses on substance as the fullest expression of self. Aristotle explains the substance of individuals in this world through their internal composition, not external forms like Plato. He uses a statue as an example: the bronze is the matter, while the statue’s form is imposed on the bronze. Change occurs when potential becomes actual. An egg is an egg in act but has the potential to become a chicken. Ontologically, act precedes potential, determining the being’s possibilities (a cat cannot become a monk). Not all potential becomes actual; the egg might be eaten instead of becoming a chicken.

René Descartes

Descartes’ Metaphysical Meditations aim to demonstrate God through logical reasoning and establish a solid foundation for knowledge. He examines the dual nature of man: res cogitans (thought) and res extensa (body). Descartes seeks truth through reason.

Meditation I

Descartes questions the reliability of knowledge based on the senses. Since senses can deceive, he doubts their trustworthiness. He also struggles to distinguish dreams from wakefulness. Descartes considers whether a benevolent God would allow deception. He concludes that an evil genius might be trapping him in error.

Meditation II

Descartes seeks to rebuild knowledge on a solid foundation. He examines the soul’s functions, as the body’s existence is uncertain. He concludes, “Cogito ergo sum” (I think, therefore I am), establishing the spirit’s existence. The body is the soul’s tool for interacting with the material world created by God.

John Locke

Locke investigates the origins, certainty, and scope of human understanding. He examines how we think, the source of human knowledge, and how we become sentient beings.

Method:

  • Investigate the origin of ideas in the mind and how they are obtained.
  • Determine the knowledge gained through understanding these ideas.

Locke calls everything the mind perceives an idea. Unlike Plato, who saw ideas as self-existent entities, Locke views them as instances formed through senses or experiences. All knowledge derives from experience; at birth, we are a tabula rasa (blank slate).

Sources of Ideas:

  • Sensation: Ideas derived from the senses.
  • Reflection: The mind’s perception of its own operations.