We owe much of our modern conception of pain to the French philosopher René Descartes
(1596–1650). Descartes believed that sensory perception does not take place in the muscles or
organs, but rather the brain. While contemplating the body-mind connection, Descartes theorized
that sensations stimulated in the body are transmitted directly to the brain, where they are actually
perceived. According to Cartesian theory, as his famous illustration of a man crouching over a
fire depicts, sensation travels along a specific, fixed “pain pathway” in the spinal cord to be
acknowledged and processed in the brain. This was a rather primitive but basically correct assessment
of nerve fibers and neurotransmitters. However, in Descartes’ model, pain is simply something
that happens to the body; it cannot originate from within, and the brain does nothing more than
passively receive pain signals from the body.