the living material being simply more complex than the non-living. The mechanists firmly believe that
ultimately life will be totally explicable in physical and chemical terms. The vitalists on the other hand
just as fervently believe that life is something more than a complex assemblage of complex parts, that
there are some life processes that are not subject to the normal physical and chemical laws, and that
consequently life will never be completely explained on a physiochemical basis alone. Central to the
vitalists doctrine is the concept of a "life force," a non-corporeal entity, not subject to the usual laws of
nature, which animates the complex assembly and makes it "alive." This concept is not only ancient,
with its roots in prehistory, but it is also practically universal, having appeared in some form or other in
all societies and furnishing the basis for the religious beliefs of most of them.
It is to the early Greek philosopher-physicians such as Hippocrates that we owe the first
organized concepts of the nature of life. These concepts developed within the framework of the
medicine of that time and were based upon some clinical observation and much conjecture. All
functions of living things were the result of "humors" liquids of mystical properties flowing within the
body. Hippocrates identified four: blood, black bile, yellow bile and phlegm-all fluids that could be
observed under various clinical conditions. At the same time the body also contained the "anima" -the
soul, or spirit of life, which made it alive. The early Greeks' knowledge of anatomy was scanty, and
while a number of Hippocrates' philosophical concepts of medicine have survived until today, none of
his functional concepts were based upon reality.
Several centuries later, as Greek influence waned, many physicians moved to the new seat of
power, Rome. Among them was Galen, trained in the Hippocratic school and although an adherent of
the humoral concept, he nevertheless felt it necessary to relate function and form in a more realistic
fashion, and so virtually single-handedly he founded the sciences of anatomy and physiology.
Dissection of the human body was prohibited at that time, so Galen was forced to base his anatomical
concepts of the human body upon dissection of animals and chance observations upon wounded
gladiators in the Colosseum. He was able, however, to produce a complete, complex biophilosophical
system based upon these anatomical observations and an expanded concept of Hippocrates' humors.
Galen's ideas were vigorously propounded and they represented such a major advance in knowledge
that they became accepted and rapidly assumed the status of dogma, remaining unchallenged for more
than a thousand years.
In the middle of the sixteenth century, Andreas Vesalius, professor of anatomy at Padua, while
trained in the tradition of Galen, began to question the validity of Galen's anatomical concepts and
performed his own dissections upon the human body, discovering that many of Galen's ideas were
wrong. Vesalius published his findings in a book, De humanis corporus fabricus in 1543, the first
anatomical text based upon actual dissection and honest observation. His greatest contribution was not
anatomical, or course, but philosophical; for the first time in more than 1500 years blind faith in dogma
had been effectively challenged by valid observation.
Twenty years after Vesalius published his revolutionary text, a young English physician,
William Gilbert, started his medical practice in London. For the next twenty-five years Gilbert,
profiting from the spirit of inquiry set free by Vesalius, combined the practice of medicine with a series
of carefully planned and executed experiments that laid the ground-work for modern physics. In 1600
Gilbert published his monumental work De magnete, in which he established for the first time the
difference between electricity and magnetism. He was the first to use the word electricity and to
introduce the concept of the magnetic field. He correctly described the earth as similar to a bar magnet
and invented the first instrument for the measurement of electric fields-the electroscope.
Gilbert's major contribution, however, was his introduction into physics of the concept of free
ELECTROMAGNETISM & LIFE - 8