Metaphysics and Cosmology: From Aristotle to Einstein

What is Real?

1. Introduction to Metaphysics

Metaphysics is the branch of philosophy that questions reality. Why do things and beings exist? What are they? Where do they come from? Being: everything that exists can be considered a being. The concept of being is very broad and general because it refers to everything that is real.

2. Essence and Existence

• Essentialism: claims that essence exists as separate realities, independent from the individuals.
• Conceptualism: essence is only incorporated into individuals who possess it or think about it.
• Nominalism: states that the term (essence) is just a name we use in order to communicate – a sort of conventional label.

3. Philosophical Positions on the Existence of God

• Theism: affirms the existence of a personal, supernatural, and transcendental god who governs reality.
• Deism: affirms that God exists and created the universe, but human reason cannot comprehend anything beyond this general notion.
• Pantheism: identifies God with nature. It claims that God is not transcendental nor a personal being.
• Agnosticism: neither affirms nor denies the existence of God. It claims that human understanding is unable to provide a satisfactory answer.
• Atheism: denies the existence of God and all supernatural beings.

4. The Problem of Metaphysics

Immanuel Kant was the first philosopher to approach the subject at the end of the 18^th century. Knowledge is the result of applying the concepts and cognitive structures in our mind to the information obtained through our senses. No progress.

The Philosophy of Nature

5. Aristotelian Cosmology

• Finite: Aristotle believed that the cosmos had to be finite because the infinite is incomplete and does not have a perfect order.
• Eternal: The cosmos cannot begin at a particular point in time because the cosmos must have originated from nothing.
• Filled with matter: Absolute not-being cannot be conceived to exist.
• Geocentric and geostatic: Earth is located in the center of the cosmos, and celestial bodies revolve around it.
• In motion: Dynamic order; all changes require a cause. When the cause ceases, changes stop.
• Divided into two spheres:
  • Sublunary sphere: covers the main section of the cosmos, starting at the Earth and reaching the sphere of the Moon.
  • Supralunary sphere: covers the expanse that begins at the sphere of the Moon and ends where the fixed stars begin.

6. The Mechanical Universe

Nicolaus Copernicus (heliocentric model):

1. The Sun is motionless and is located in the center of the universe.
2. Planets revolve around the Sun in circular orbits.
3. The Moon revolves around the Earth.
4. 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.

Galileo Galilei:

1. Limited the field of research to questions whose answers are verifiable using sensory experience.
2. Properties that can be analyzed independently and mathematically are length, temperature, and mass.
3. Improved the quality of scientific instruments, such as the telescope.
4. Developed arguments against the errors of the geocentric model.

Johannes Kepler: Celestial bodies move in perfect circles.

Isaac Newton: The law of universal gravitation affected all bodies, both celestial bodies and those found on Earth's surface. This theory was accepted.

7. Contemporary Cosmovisions

1. The principle of entropy: any physical process is reversible.
2. Light behaves like a particle and, at other times, like a wave.
3. James Clerk Maxwell developed an electromagnetic theory in which forces do not act in a straight line.

Albert Einstein's theory of relativity described astronomical speeds and magnitudes. Quantum mechanics involves studying microscopic phenomena. Einstein believed that:

1. Space and time are relative.
2. Light propagates in a vacuum at a constant speed.

He proposed a general theory of relativity (1916) and then added gravitational fields. In his second version, gravitational fields are the result of the deformation of space, not a result of the forces of attraction by the mass of bodies.

Max Planck discovered that matter absorbs and emits energy discontinuously. Niels Bohr designed an atomic model with defined orbits for electrons. Two new theories are Chaos Theory and the Big Bang Theory.

Edward Lorenz's chaos theory states that any small variation can produce enormous differences. The Big Bang Theory states that the universe is not static but rather dynamic.