Historical Cosmologies

Historical Cosmologies

Cosmology and the Origin of Life

Moving Towards a Geocentric Cosmology

A Scientific Perspective:

Three biases from this perspective:

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:

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:

Now comes geometry and the concepts of perfection. Culturally this seems like a natural harmonious meld with the Cosmos:

Pythagoras Geometry! a2 + b2 = c2

To Plato, making a model for Astronomy seemed relatively simple. All one had to do was to provide an explanation which would account for the highly ordered motions of the planets as observed from the Earth.

Over time this lead to Aristotle's Cosmology of the Crystalline Spheres:

Aristotle and Plato:

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 Huge Cultural Bias.

Furthermore, Aristotle tells us that the Universe is perfect and unchanging.

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!

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: