The concept of a homunculus (Latin for "little man", sometimes spelt "homonculus") is often used to illustrate
the functioning of a system. In the scientific sense of an unknowable prime actor, it can be viewed as an entity or agent..
The term appear to have been first used by the alchemist Paracelsus. He once claimed that he had created a false human being that he referred
to as the homunculus. The creature was to have stood no more than 12 inches tall, and does the work usually associated with
a golem. However, after a short time, the homunculus would
turn on its creator and run away. The recipe consisted of a bag of bones, sperm, skin fragments and hair from any animal you
wanted it to be a hybrid of. This was to be laid in the ground surrounded by horse manure for forty days, at which point the
embryo would form.
Needless to say, this procedure does not actually produce a
viable homunculus, nor do the variants cited by other alchemists. One such variant involved the use of the mandrake. Popular belief held that this plant grew where semen ejaculated by
hanged men (during the last convulsive spasms before death) fell to the ground, and its roots vaguely resemble a human form
to varying degrees. The root was to be picked before dawn on a Friday morning by a black dog, then washed and "fed" with milk
and honey and, in some prescriptions, blood, whereupon it would fully develop into a miniature human which would guard and
protect its owner. Yet a third method, cited by Dr. David Chritianus at the University of Gieseen during the 18th
centruy, was to take an egg laid by a black hen, poke a
tiny hole through the shell, replace a bean-sized portion of the white with human sperm, seal the opening with virgin parchment,
and bury the egg in dung on the first day of the March lunar cycle. A miniature humanoid would emerge from the egg after thirty
days, which would help and protect its creator in return for a steady diet of lavender seeds and earthworms.
The term homunculus was later used in the discussion of conception
and birth. In 1694, Nicholas Hartsoeker discovered "animalcules" in the sperm of
humans and other animals. Some claimed that the sperm was in fact a "little man" (homunculus) that was placed inside a woman
for growth into a child; these later became known as the spermists. This is not as silly as it sounds today, and neatly
explained many of the mysteries of conception (for instance, why it takes two). However it was later pointed out that if the
sperm was a homunculus, identical in all but size to an adult, then the homunculus must have sperm of its own. This led to
a reductio ad absurdum, with a chain of homunculi "all
the way down".
Today the term is used in a number of ways to describe systems
that are thought of as being run by a "little man" inside. For instance, the homunculus continues to be considered as one
of the major theories on the origin of consciousness,
that there is a part (or process) in the brain whose purpose is to be "you". The homunculus is often invoked in cybernetics as
well, for similar reasons.