Ancient Science vs. Scientific Revolution: Cosmos View

Ancient Science: The Closed World

The vision of the cosmos in ancient science is based on a geocentric model. This worldview, beginning in ancient Greek cosmologies and extending into the Renaissance, convinced humanity for over two thousand years that the Earth was the center of the universe. Geocentrism is the defining characteristic of the ancient worldview.

Aristotle believed the universe was divided into two levels:

• The lower or sublunary world, below the Moon's orbit, is imperfect and corruptible.
• The upper or supralunar world, beyond the Moon, is perfect and incorruptible, containing planets and stars composed of ether or quintessence.

The sublunary world is composed of four elements: earth, air, water, and fire. The cosmos is a closed and finite system, a system of dynamic fields where everything that moves is moved by another. Ultimately, there is a first unmoved mover that moves the whole cosmos. This system is marked by an end; everything is directed to comply with an order. It is, therefore, a teleological model.

In the second century, Ptolemy, an astronomer of the Alexandrian School, adopted Aristotle's geocentrism and developed the system of "epicycles." This system explained the anomalies in the retrograde motion of the planets. The Ptolemaic system remained in force until the Renaissance and the arrival of advances in astronomy from Copernicus.

The Scientific Revolution: The Open Universe

Copernicus is the father of heliocentrism, and with him begins a new vision of the cosmos that applies to this day. The new model is that of an open, infinite, and homogeneous universe whose center is the Sun. The planets revolve around it in elliptical, not circular, orbits. It is a model in which everything is predictable, everything is determined by necessary laws.

Copernicus questioned the old Aristotelian division of the cosmos into two levels or orbs. He placed the Sun at the center and conceived a homogeneous universe in which Earth was no longer the center.

Features of the Copernican model:

1. Heliocentric
2. Homogeneous cosmos
3. Infinite cosmos
4. Elliptical orbits

This new worldview was completed by Newton. Newtonian physics finally completed the new image of the cosmos designed for modern science. The entire universe is subject to the law of universal gravitation. The cosmos is infinite, dimensionally homogeneous, and is not governed by a particular end.