Socrates was a Greek philosopher who lived in the 5th century BC. He is considered to be one of the most important figures in the history of Western philosophy, but he is not a Pre-Socratic philosopher.

The Pre-Socratic philosophers were primarily concerned with understanding the nature of the universe. They sought to explain the origin and structure of the cosmos, as well as the forces that govern it.

Thales of Miletus proposed that the universe is made up of a single, primary substance, which he identified as water. He believed that all things in the universe are derived from water and that water is the source of all life.

Anaximander proposed that the primary substance of the universe is apeiron, which is an infinite and indeterminate substance. He believed that apeiron is the source of all things and that all things are derived from it.

Anaximenes proposed that the primary substance of the universe is air. He believed that air is the source of all things and that all things are derived from it.

Heraclitus proposed that the universe is in a constant state of flux. He believed that everything is constantly changing and that nothing remains the same. He also believed that opposites are interconnected and that they are necessary for each other's existence.

Heraclitus believed that opposites are interconnected and necessary for each other's existence. He argued that without opposites, there would be no change or motion in the universe.

Pythagoras proposed that the universe is governed by a rational order. He believed that mathematics is the key to understanding the universe and that the universe is governed by mathematical principles.

Pythagoras believed that mathematics is the key to understanding the universe. He argued that the universe is governed by mathematical principles and that mathematics can be used to understand the structure and order of the universe.

Democritus proposed that the universe is made up of atoms. He believed that atoms are the smallest and most basic units of matter and that all things in the universe are made up of atoms.

Democritus believed that atoms are indivisible and indestructible, that they are made up of smaller particles, and that they are in constant motion.

Empedocles proposed that the universe is made up of four elements: earth, air, fire, and water. He believed that all things in the universe are made up of these four elements and that they can be combined in different ways to create different substances.

Empedocles believed that the four elements are constantly changing and transforming into each other. He argued that this process of change is driven by two forces: love and strife.

Parmenides proposed that the universe is made up of a single, infinite substance. He believed that this substance is unchanging and indivisible and that it is the source of all things.

Parmenides believed that change is an illusion. He argued that the universe is unchanging and indivisible and that any appearance of change is simply a result of our limited perception.