The Evolution of Worldviews: From Ancient Greece to Modern Cosmology

Posted on Dec 1, 2024 in Social sciences

1. Worldviews and the Origin of the Universe

Worldviews address fundamental questions about the origin of the universe and natural phenomena. They offer coherent and systematic ways of seeing and understanding the world.

1.1. Defining a Worldview

A worldview is any interpretation of reality that provides a coherent and systematic framework for understanding the world.

1.2. Scientific Worldviews

Max Weber’s concept of the “disenchanted world” reflects how modern science has shifted humanity’s vision of its place in the universe. We have moved from the center to the periphery.

  • Science plays a key role in shaping worldviews.
  • Astronomy: Studies the movements of stars and the laws governing them.
  • Cosmology: Investigates the origin and development of the universe.
  • Physics: Establishes fundamental laws explaining forces and motion.

1.2.1. The Evolution of Scientific Worldviews

Scientific worldviews have evolved throughout history, sharing some common traits:

  • Explaining the form and structure of the universe.
  • Describing humanity’s position in the world.

Key Worldviews:

  • Ancient Worldviews: Explanations of reality emerging in Greece from the 6th century BC.
  • Modern Worldview: The image of the world shaped by the scientific revolution of the 16th and 17th centuries.
  • Current Worldview: Based on the theory of relativity and quantum mechanics.
1.2.2. Ancient Worldviews

Early worldviews stemmed from the observation of regular celestial movements contrasted with the diverse and variable phenomena on Earth. This led to the belief that heaven and earth were distinct realms.

Anaximander’s World: A fiery layer of the universe explodes, creating igneous bodies enveloped in mist, rotating around the earth and sea. Celestial bodies are holes in these fiery tubes, through which the fire shines. Eclipses are the sealing of these holes.

2. The Principles of Reality

Ancient thinkers believed that the diversity of substances in nature could be reduced to a few basic elements:

2.1. The Arché (or Arkhé)

The beginning or origin: All things arise from one or more elements through transformations. Examples include:

  • Anaximander: Apeiron (the unlimited or infinite)
  • Anaximenes: Air (condensation/rarefaction)

2.2. The Four Elements

All things are a mixture of four elements (water, air, earth, and fire) and two processes (Eros, union; and Neikos, separation).

2.3. The Earth

2.3.1. The Shape of the Earth

Early explanations envisioned a flat earth surrounded by water. By the 5th century BC, Pythagoreans proposed a spherical Earth based on observations like the disappearance of ships’ hulls over the horizon and the circular shadow of Earth during lunar eclipses.

2.4. The Sky

Ancient explanations of the sky were intertwined with Greek religious beliefs and emphasized the circular motion of celestial bodies.

  • Geocentrism: The Earth is stationary at the center of the universe.
  • Finite Universe: The universe is bounded by the sphere of fixed stars.

2.4.1. Plato’s Problem (Retrogradation)

While stars move regularly in perfect circles around the Earth, planets exhibit erratic movements. Explaining these movements through circular motion posed a challenge.

2.4.2. Eudoxus of Cnidus and the Theory of Concentric Spheres

Eudoxus proposed 27 concentric spheres centered on Earth. These crystalline, interconnected spheres explained planetary motion through combined movements.

2.4.3. The Aristotelian Cosmos

Aristotle’s cosmos consisted of two distinct worlds:

  • Sublunar World (Earth): Composed of four elements, each moving towards its natural place. Characterized by linear motion, generation, and corruption. Motion is driven by friction from outer spheres.
  • Supralunar World (Celestial): Composed of ether (perfect, pure, unchanging, and weightless). Characterized by uniform circular motion, immutability, and eternity. Driven by the Prime Mover (Unmoved Mover).

2.4.4. The Ptolemaic Cosmos

Ptolemy’s model placed Earth slightly off-center. Planets revolved around Earth on a deferent, with an additional circle called an epicycle on which the planet moved. This combination explained retrograde motion.

2.4.5. Ptolemy’s Almagest

Claudius Ptolemy (138-180 AD) formalized his cosmological system in the Almagest.

2.4.6. Ptolemy’s Model and its Deficiencies

Ptolemy’s model struggled to explain variations in planetary brightness and speed.

2.5. Philosophical Implications of an Ordered Reality

  • Order and Predictability: The universe is organized and predictable.
  • Knowability: Reality is rational and can be understood.
  • Anthropocentrism: Nature is made for human scale and reason.

3. Modern Worldviews and the Scientific Revolution

The 16th century marked the beginning of the Scientific Revolution, emphasizing experimentation, new physics, and mathematical rigor. This led to a shift from a heterogeneous world to a homogeneous one governed by universal laws.

3.1. Contributions to the New Worldview

The Copernican system retained some ancient characteristics (finite universe, circular motion, uniform velocity) but was further developed by Kepler and Galileo.

3.1.1. Johannes Kepler (1571-1630)

Kepler provided mathematical support for heliocentrism with his laws of planetary motion:

  1. Elliptical orbits with the sun at one focus.
  2. Equal areas swept by the radius vector in equal times.
  3. Planetary speed depends on distance from the sun.

3.1.2. Galileo Galilei (1564-1642)

Galileo pioneered the use of the telescope for scientific observation, confirming heliocentrism experimentally. His discoveries included sunspots, lunar craters, Jupiter’s moons, and the vastness of the universe.

3.2. The New Physics

Galileo and Newton discovered physical laws explaining planetary motion:

  • Law of Inertia (Galileo): Bodies remain at rest or in motion unless acted upon by a force.
  • Law of Universal Gravitation (Newton): Bodies attract each other with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.

This marked the end of Aristotelian physics and the rise of a new model based on universality and prediction.

3.3. Philosophical Implications of the Copernican Turn

  • Mechanism: The world is like a perfect machine (clock).
  • Determinism: Physical laws determine all events.
  • Diminished Role of God: God is reduced to creator and designer.
  • Importance of Nature: Nature is self-sufficient.
  • Insecurity: Humans become aware of their weakness.
  • Power of Reason: Reason can unlock nature’s secrets.