dualisme

Dualisme was coined by Thomas Hyde in 1700 (in Latin, as dualisma) to describe the Zoroastrian religion's division of reality into good and evil principles — Ahura Mazda versus Angra Mainyu. The word comes from Latin dualis (containing two), from duo (two). Hyde was writing about Persian theology, not European philosophy, but the word soon migrated.

Christian Wolff applied 'dualism' to philosophy in 1720 to describe the position that mind and body are two fundamentally different substances. This was Descartes' view, articulated in his Meditations (1641): the body is extended substance (res extensa), occupying space and following mechanical laws. The mind is thinking substance (res cogitans), unextended, without spatial location. The two interact — your decision to raise your arm causes your arm to rise — but how two completely different substances interact remained a mystery. Descartes suggested the pineal gland as the meeting point. Nobody found this convincing.

The mind-body problem, as it became known, has generated more philosophical literature than almost any other question. Leibniz proposed pre-established harmony — mind and body run in parallel like synchronized clocks. Spinoza proposed monism — mind and body are two aspects of one substance. Gilbert Ryle called Descartes' position 'the ghost in the machine' in 1949. The phrase stuck.

Neuroscience has made dualism increasingly difficult to defend. Brain damage changes personality. Chemicals alter consciousness. Electrical stimulation produces specific thoughts and sensations. The evidence points toward the mind being what the brain does, not a separate substance. But the intuition persists — the feeling that your consciousness is something different from your neurons. The word dualism names a problem that refuses to dissolve.