Galen became a true pioneer when he performed anatomic
experimentation. Tragically, it involved vivisection, but instead of
conjecture about the imbalance of humors, Galen became the first to
uncover organ function. “By tying and untying the ureters Galen proves
the flow of urine from the kidneys to the bladder; he severs the spinal cord
at different levels and describes the ensuing loss of motion and sensibility;
he ligates the recurrent nerves [that lead from the brain to the vocal cords]
and he has discovered and notes the subsequent loss of voice.”^15 This 2nd
century natural philosopher upended centuries of Aristotelian theory about
the heart being the “command center” of the body, and instead
demonstrated that the nerves carried the impulses to the muscles from the
brain.
Why do we breathe? The Greco-Roman philosophers had no concept of
oxygen, and were left pondering the role of respiration and conjectured
that there was a pneuma, a vital spirit, that must be drawn in to infuse the
body. The psychic pneuma, Galen concluded, must well up from the net-
like plexus of arteries at the base of the brain, what he termed the rete
mirabile, and travel to the ventricles, the fluid-filled caverns in the middle
of the brain. As Galen had established that impulses must originate in the
brain, the empty space of the ventricles must be the domicile of the
psychic pneuma. Galen’s rete mirabile, the fount of the psychic pneuma,
would become a major issue 1,300 years later, but for now, Galen had led a
critical revolution in deciding that cognition originated in the brain.
Near the end of Galen’s life, at the end of the 2nd century, “peace and
stability collapsed, and for about a hundred years political conditions close
to anarchy disrupted cultural and economic life.”^16 Eventually, barbarian
incursion on Roman soil destabilized the empire. In one of the most
impactful developments in Western civilization, the emperor Constantine
made Byzantium (which he renamed Constantinople, modern day Istanbul)
his capital in 330 C.E. Rome and Constantinople were dual capitals for
decades, but in 395 C.E., after the death of the emperor Theodosius, the
empire was divided permanently between the Latin West and East. By the
late 400s, Rome was in full collapse, and the Latin Middle Ages would last
for one thousand years.
One cannot comprehend Western civilization without understanding the
(temporary) survival of the Roman Empire in Constantinople for hundreds
of years. “While the West was on its way to the Latin Middle Ages, the