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Cosmology and the Origin of Life
The Rules:
Making Models:
Early Cultures were curious and motivated to explore the world
no one was ignorant because everything was new but the
process of learning can begat ignorance through the death of
imagination
The First Cosmology:
The Second Cosmology: Evolving Towards the Hierarchical Viewpoint
Some Example Myths as Cosmological Models
ORIGINAL IDEA:
Everything was created in a Single EventEverything was created in a Single Event |
The Third Cosmology:
Geometric Universe:
Sky Observations Motion
Constellations
All of this started about 4000 years ago
Greeks refined the geometric universe (and stole a lot of th
e
math from the Babylonians).
They defined Four Primal Beings as being dominant in their cosmological model:
Now we have various combinations of gods and sub-gods getting together to help populate the earth:
Pandora Releases Evil Secrets that Prometheius had locked
away
Three biases from this perspective:
Science itself is a process which maps out the unknown. It
is not a process that converts the unknown to the known nor is it
a method to discover the "truth".
There is nothing perfect about SCIENCE. Its
beauty and truth lie in its intrinsic uncertainty.
So lets' start around 600 BC. By this time Greek Culture was quite well defined and the idea of Law, as a means of establishing order was firmly in place. If society itself could be "governed" by a set of rational laws, then clearly Nature must be similarly governed.
Hellenistic Culture(~600 B.C.):
The ancient Greeks inherited astronomical records from the Babylonians and applied the data to construct a cosmological framework. Data was not just used for practical goals, such as navigation, but also to think of new experiments = natural philosopher.
Fine Tuning the Cosmos: Identifying its essential Ingredients
600 BC
Greeks start to dissect the world into component pieces:
ORIGINAL IDEA ALERT:
Now we have CAUSE and EFFECT and the first hints of the physical nature of the Universe.
There are three components to cause and effect:
An Alternative to the idea that something is most important:
500 BC:
Democritus: The Universe consists of atoms and the Void;
all else is opinion and illusion
Collisions between atoms formed the Universe
The Universe runs by Itself
Quantum Mechanics has just been expressed. That is, the universe can exist without anyone in it
The Greeks constructed their whole theory of the Universe on the concepts of numbers and shape, arithmetic and geometry. An example of this was when Empedocles discovered that there exist only 5 regular solids. This ultimately leads to Plato's Theory of Forms .
Plato, so impressed by the elgence of this discovery, then proposed that four of these solids correspond to the four atomic elements in the Universe (earth, water, air and fire). The fifth element corresponds to the Cosmos:
Pythagoras
Now comes geometry and the concepts of perfection. Culturally this
seems like a natural harmonious meld with the Cosmos:
Geometry!
a2 + b2 = c2
Over time this lead to Aristotle's Cosmology of the Crystalline Spheres:
In the center of the painting are Aristotle and Plato, Aristotle's hand level to the Earth symbolizing his realism view of Nature; Plato's hand pointed towards the heaven symbolizing the mystical nature to his view of the Universe. |
Aristotle stands in the Greek philosophical tradition which asserts that nature is understandable. This tradition, opposed to the idea that nature is under the control of capricious deities which are to be appeased rather than understood, is one of the roots of science.
However, one must be careful to assert that nature is not completely understandable
Aristotle constructed his view of the Universe based on a intuitive feeling of holistic harmony. Central to this philosophy was the concept of teleology or final causation. He supposed that individual objects (e.g. a falling rock) and systems (e.g. the motion of the planets) subordinate their behavior to an overall plan or destiny.
His theory of motion flows from his understanding of matter as constituted of four elements: air, earth, fire, and water. Objects, being solid like earth, would tend to clump together with other solids (earth), so objects tend to fall to earth, their natural place. Thus, falling is a natural motion.
To avoid the idea that their is an infinite chain of causes, Aristotle argued that there
must be an "unmoved mover," something which can initiate motion without itself being
set in motion today we
might call this gravity!
Aristotle introduces the Two Sphere Universe. This is a FINITE Universe that you can now draw the Universe on a piece of paper!
We have come a long way from the world view that everything had a common origin (e.g. the Cosmic Womb in the Mythic Universe):
The Earth lies at the
Center of the Two Sphere Universe and everything revolves around it
Clearly, imagination has now vanished. We have a deterministic
model of the Universe (e.g. two spheres) and we think that
all is figured out!
Huge Cultural Bias.
Now all is in harmony, the earth is at the center of the universe and the cosmos revolves around us in perfect contentment
Elements of the Universe at this time (Aristotle):
But there are observational problems:
Aristarchus (270 B.C.) developed the heliocentric theory
Measuring the Circumference of the Earth:
Eratosthenes (220 B.C.) - The early Greeks knew the Earth was a sphere based on the shadow of Earth on the Moon during lunar eclipses. Eratosthenes proceeded to use this information to measure circumference of Earth in the following manner; he knew that on a certain date that a stick placed in the ground at Syene cast no shadow. Whereas, a stick at Alexandria has a small shadow. Using simple ratios he showed the following:
Geocentric model was so popular that it stood for 1500 years.
Back to the Original Idea Alert:
Cardinal Nicholas of Cusa (15th Century) through a lot about
cosmology and came up with the following;
The above two means there can be no UNIQUE place in the Universe
Copernicus embraces the non-uniqueness idea and then asks why should the earth be at the center - lets put the SUN there
Evolving Models of the Solar System and The Scientific Method:
Kepler's laws are only empirical they have
no dynamical basis. Therefore, they would appear to be magic as they
have no physical explanation (yet). (see page 16 in the book).