The Evolution of Human Nature in Western Philosophy

Core Theories of Human Nature

• Dualism: Human beings consist of both matter and spirit.
• Materialist Monism: Human beings consist solely of matter.
• Spiritualist Monism: Human beings consist solely of spirit.

Plato: Metaphysical Dualism

Plato proposed a dualistic view consisting of two worlds: the higher world of absolute standards and concepts, and the lower world of physical, particular things encountered through the body.

Aristotle: Matter and Form

Aristotle argued that humans are composed of matter and form. The body is matter, while the soul (psyche) is the immaterial form that organizes that matter. He identified three types of soul:

• Vegetative soul: Found in plants; governs nutrition, growth, and reproduction.
• Sensitive soul: Found in animals; allows for perception and movement in response to stimuli.
• Rational soul: Unique to humans; permits representation and abstract thought.

Thomas Aquinas

Aquinas reinterpreted classical philosophy to align with Christian faith, detailing a strict, religious, and hierarchical structure of all matter and life as decreed by God.

Thomas Hobbes: Materialism

An admirer of modern science, Hobbes stated that reality is matter in motion. He argued that all bodies are composed of atoms moving through space according to mechanical laws.

David Hume: Empiricism

As a staunch empiricist, Hume sought to create a naturalistic science of man. He argued against the existence of innate ideas, proposing instead that mental behavior is governed by custom.

Immanuel Kant: Reason and Morality

Kant synthesized rationalism and empiricism, arguing that both the laws of nature and morality are grounded in human reason. He is particularly noted for his theory of a single moral obligation.

Sigmund Freud: The Unconscious

Freud developed theories regarding the unconscious mind and the mechanism of repression. He viewed human beings as biological creatures driven by strong instincts.

Jean-Paul Sartre: Existential Freedom

Sartre famously stated that humans are "condemned to be free." His theory posits that because there is no Creator, human beings have no predetermined essence before their existence.