For
two thousand years, Aristotle's worldview held sway for Western
civilization. Aristotle believed that the Earth was geostatic
(unmoving) and geocentric (the focal and central point of the
universe). As to whether the earth was flat or round, this was
something that was actually beyond debate in those times.
In
fact, only the uneducated and primitive people believed the earth to
be flat. This issue about the shape of the earth had already been
settled by philosophers and scientists, and they did not think the
earth to be flat. It may come as a surprise that certain people would
insist otherwise despite evidence to the contrary, but we do not need
to look too far today, i.e. intelligent
design
to find similar strains of foolishness floating around.
The
whole Copernican controversy was more about the earth's location,
whether it had a geocentric or heliocentric position, and its
behavior, whether it was static or moving. As mentioned, the
Aristotelian worldview of the earth as motionless and geocentric
stood firm for two thousand years until the heliocentric Copernican
revolution toppled it over.
According
to the Aristotelian worldview and philosophy, there are fundamental
pairs of physical opposites of hot and cold, humid and dry in the
universe. These pairs are then combined to create the four elements,
where earth consists of cold and dry; water is a mixture of cold and
humid; air a combination of hot and humid, while fire was thought to
be made of hot and dry.
Depending
on its materials, each element would have a specific given and
natural direction. For example, earth and water would generally move
straight downwards, while air and fire would move straight upwards.
This underscores the reasoning behind and concept of natural motion.
Bodies tend to move toward their natural and proper resting place.
And, in fact, motion is the opposite of rest since once bodies have
found their place, they will not budge unless moved by others, that
is an external agent.
So
we can see Aristotle believed that earth and water have weight
(gravity)
and are hence “heavy bodies.” The natural state of bodies is that
they remain at rest. Hence in such a worldview a rotating earth did
not make much sense.
Moreover,
it is important to note that bodies on earth do no emit light much
unlike the stars that are in the heavenly spheres. Even fire does not
emit its own light but only does so when it is escaping from the
lower regions to find its own proper place upwards, that is in the
heavenly spheres.
While
the heavy bodies tend to be at rest on our planet, air and water have
levity and are light bodies; these light bodies are helped to travel
via the fifth (and most mysterious) element called aether, which was
supposed to be luminous, this being one of its most significant
properties or characteristics.
Now
nothing moves on its own as all bodies prefer to reach the natural
end state of motion, which is its opposite, namely rest. They would
remain so because that is their internal state. Once they have found
this state, they can be moved only externally, that is by an external
agent, which can be a person, for example, picking up a pebble from
the beach and throwing it, or the wind that is blowing the leaves
about.
So if the heavenly spheres are rotating around the center of universe, they must be started by some mover, in fact, the sublimely mysterious unmoved mover. This motion is referred to as primum mobile, meaning simply the first body in motion. It is these constantly moving spheres that carry planets and stars with them in continuous circular motion.
Where
the earth's natural state is bodies at rest, the important
characteristic of the heavens is motion. (In fact, in the heavenly
sphere, there are both fixed and wandering stars. Only seven of these
stars were considered to be wandering and hence they were called
planets, which means, yes, wandering
star.)
Not
bad, Aristotle, but in comes Copernicus to shake things up a little
and to put things upside down. Copernicus proposed a heliocentric
model and that the earth was not static but moving. In fact, the
ideas of Copernicus were not new but had already been proposed by
ancient Greek philosopher Pythagoras and others; what Copernicus did
was merely reinterpret the available information.
One
of the strong points of Copernican theory was that his explanation
was simpler, more elegant and more systematic because instead of
having the heavenly spheres with thousands of stars moving about,
there is only one body moving, namely the earth.
This
heliocentric theory was approached like any body in motion, that is,
with resistance and opposition. This resistance occurred due to
biblical objections. The Protestants who had a more literal approach
and interpretation of the Scripture tended to object the most and
strongest.
When
it came to the Catholics, they referred, when in doubt, to the Church
Fathers for guidance and illumination. And it turned out that pretty
much all of these noteworthy fathers put Aristotle on a pedestal and
believed that the geostatic system was the correct one to be
espoused, while anything that was otherwise ought to be officially
declared as heretical. That also became the Church's official
position until rather recently when the Church in 1992 accepted that
Galileo was right after all, more than 350 years later!
So
after Copernicus the grounds were set for Galileo to enter the scene.
Galileo following his father's footsteps used the experimental
approach for his findings and discoveries. In fact, one of his
greatest and most revolutionary deeds of the times was to point the
telescope upwards to watch the skies. His new and improved lenses
made leaps and bounds in astronomy and added precision since his
observations ended up being much more reliable than naked-eye
observations.
But
alas, Galileo was not given free reign in his discoveries. He was
considered a heretic by the Inquisition who deemed his proposed
theories on the earth's motion as false and as a dangerous threat to
Catholicism as a whole. Galileo had lost his general support in the
Vatican and was threatened with torture on the basis of “vehement
suspicion of heresy.” However, he managed to escape a lengthy
prison sentence and it all lead to house arrest instead.
Why
was the Church so obsessed with the earth's position and motion and
so opposed to the new science? One of the reasons apart from
scriptural authority was that the world was seen as a perfect
embodiment created by God, or rather His unique masterpiece. This led
to a view of teleological anthropocentrism, which means that the
whole universe exists merely for the sake and benefit of humankind.
This
is also related to Aristotle's view regarding heavenly bodies, which
are closer to God and are perfect in themselves because they do not
change and hence are eternal like its Creator. On the other hand, the
earth is far from perfect. We find that the earth changes and that
life and things down here are corrupt and dirty; they die and
decompose and thus have transitory existence.
It
is through pure mathematics that we can reveal God's works since
mathematics as opposed to the sciences gives us the same objective
certainty that God has. There is no - or much less resistance to -
doubt, whereas in other fields we must be aware of our senses, which
can, according to Plato, deceive us in various ways.
Yet
it is important to note that Galileo is not using one method but
rather relies on logic (apart from physics naturally) in his
arguments, logic not in the sense of a theory of reasoning but which
also includes theories of knowledge, as method as well as science. He
combines his observations of moving ships and gunshots (all of which
went beyond my own head and my limited reasoning capacities) with
detailed logical analysis.
As
a result, his Dialogue
becomes a synthesis of astronomy, physics, and epistemology. It is,
in fact, a fascinating work and it is presented in detail and with
clearly presented arguments and reasons in The
Routledge Guidebook to Galileo's Dialogue
written and expounded expertly by Maurice A. Finocchiaro, albeit the
book is at times too complicated and complex for this scientifically
and logically untrained mind of mine.
My only caveat is that those who would like to read this guidebook to better understand Galileo's work and theory be better equipped with some physics and mounds of logic, and thus they will reap even more benefits than I was able to unearth for myself.
My only caveat is that those who would like to read this guidebook to better understand Galileo's work and theory be better equipped with some physics and mounds of logic, and thus they will reap even more benefits than I was able to unearth for myself.


