Descartes’ Philosophy: Mind, Body, and the World
Descartes’s Exploration of Knowledge and Substance
The Wax Argument and Sensory Perception
Descartes, using the example of a piece of wax, questions how we understand physical objects. While our senses initially perceive qualities like shape, texture, and scent, these change when the wax melts. Yet, we still recognize it as the same piece of wax. This leads Descartes to conclude that true understanding comes not from the senses, but from reason.
Mind-Body Dualism
Descartes’s philosophy is fundamentally dualistic, positing a radical difference between the mind (soul) and the body. He argues that we can doubt the existence of everything, including our bodies, but not the existence of our doubting minds. This “thinking” self becomes the foundation of his philosophy, famously expressed as “I think, therefore I am.”
This thinking substance, independent of the body, is easier to know and, according to Descartes, immortal. The body, on the other hand, is subject to physical laws and is not essential to our existence as thinking beings.
Descartes’s Metaphysics of Substance
Substance, for Descartes, is the foundation of knowledge. He identifies three innate ideas: the soul, God, and the physical world. Substance is that which exists independently and needs nothing else to exist. Substances possess attributes that constitute their essence.
- Divine Substance: God’s mind is infinite, incomprehensible, and perfect. God is the cause of motion in the world and guarantees the existence of finite substances (thinking and extended).
- Thinking Substance: The mind’s essential attribute is thought, with modes such as willing, feeling, and deciding. Thinking defines human existence.
- Extended Substance: The physical world’s attribute is extension, with modes of figure and movement. These are measurable mathematically and geometrically.
Descartes’s Physics and Anthropology
A Mechanistic Worldview
Descartes’s physics is mechanistic, inspired by inventions of his time. He views the world as a vast, extended machine governed by laws of motion. Movement is extrinsic, originating from God, the prime mover. Secondary causes, like the principle of inertia and the conservation of motion, derive from God’s initial impetus.
The Nature of Humans
Humans, unique among beings, are composed of two substances: mind and body. The soul, the defining characteristic of humanity, is a non-extended reality, while the body is extended and subject to mechanical laws. The soul’s immortality stems from its independence from the body.
Will resides in the soul, while feelings originate from the external world and are reflected in the soul. Error, according to Descartes, arises not from God, who is perfect, but from the misuse of human freedom. Error can be avoided by careful reasoning and limiting the will’s influence on understanding.