Metaphysics, Scientific Method, and Cosmology: A Historical Overview

Introduction to Metaphysics

Metaphysics is a branch of philosophy which questions reality. Why do things and beings exist? What are they? Where do we come from? Metaphysical doctrines have always been developed to oppose rival doctrines.

Metaphysical categories: unity-plurality, reality-appearance, essence-existence, necessity-contingency, matter-spirit

Metaphysical doctrines: monism-pluralism, essentialism-existentialism, materialism-dualism

The Criteria of Demarcation

The Criteria of Demarcation For science to be considered scientific, criteria were established to distinguish between what is a scientific discipline and what is not. Verificationism and falsificationism propose two different sets of criteria.

Verificationism states that only theories that are verified through experiments can be considered scientific. The verification of a scientific law or theory consists of proving that what is established is true in all cases under consideration

Falsificationism is based on the idea that, although we cannot verify or prove scientific laws or theories indisputably, it is possible to prove that they are conclusively false through experience.

The Scientific Method

The Scientific Method There are two fundamental models of the scientific method: the classical and the modern.

According to the classical model, the scientific method has two phases:

• Inductive phase: general laws are established using objective data gathered from a process of generalization. This process must meet three requirements: It must involve a great number of observations. The observations must be made in a wide range of different circumstances. No statement based on observation may contradict the universal law obtained
• Deductive phase: A universal law is chosen; it is related to a specific case; and an explanation or prediction of a phenomenon is made

There are some problems with the classical model: lacks necessary solidity and the first two requirements are vague

The modern model or the hypothetico-deductive method was developed by Galileo. It consists of these steps: posing a problem, gathering empirical data, formulating an explanatory hypothesis, deducing observable consequences and experimental testing

Aristotelian Cosmology

Aristotelian Cosmology

Aristotle was the first person to attempt to give a rational and systematic explanation of the ordered Universe. He wanted to develop a model of a Universe which had a logical order, so he created a system that incorporated the doctrines proposed by his predecessors in a coherent way. The resulting Universe had the following characteristics:

• Finite: Aristotle believed that the cosmos had to be finite because ‘infinite’ is synonymous with ‘incomplete’. Something incomplete cannot have a perfect order.
• Eternal: the cosmos cannot begin at a particular point in time because otherwise the cosmos would have originated from nothing.
• Filled with matter: there is no void. The void is absolute not-being, and not-being cannot be conceived to exist. As a result, the Universe is filled with matter.
• Geocentric and geostatic: the motionless Earth is located at the center of the cosmos. All other celestial bodies revolve around the Earth.
• In motion: the cosmos has a dynamic order. All changes require a cause: when the cause ceases, the changes stop.
• Divided into two spheres: the sublunary and superlunary spheres.

During the 2nd century BC, Ptolemy tried to link the logical perfection of the Aristotelian model with observable facts. The Universe, as conceived and described by Ptolemy was geocentric, just as in Aristotle’s model. The orbits were eccentric, in addition the planets moved in orbits known as epicycles.

The Ptolemaic model of the Universe constitutes the greatest astronomical work in Ancient History.

The Mechanical Universe

The Mechanical Universe

During the 16th century, Nicolaus Copernicus proposed a theory which contradicted the geocentric model: the heliocentric model. The main characteristics of the Copernican Universe are:

• The Sun is motionless and is located at the center of the Universe.
• The planets revolve around the Sun in circular orbits. The eccentric orbits and epicycles are still used to locate the positions of the planets.
• The Moon revolves around the Earth.
• The Earth moves in three ways: rotation on its axis, revolution around the Sun and the tilting of its axis with respect to the ecliptic plane.

With the Earth no longer at the center of the Universe, people began to think about the world and the role of human beings in a different way. This is because humans no longer held the privileged position of the geocentric model.

The role of Galileo Galilei in providing physical evidence to support Copernican astronomy was key.

Johannes Kepler put an end to the Aristotelian belief that the most perfect geometric shape was the circle. Kepler's first law replaces circular orbits with elliptical ones.

Newton stated that the law of universal gravitation affected all bodies: both celestial bodies and those found on the Earth’s surface. This was the first time in history that the concept of a single universe was accepted, as opposed to the two regions, or spheres, as proposed by Aristotle (sublunary and superlunary).